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acrac_3158170_2

Dialysis Fistula Malfunction

As high as 90% of accesses with abnormal physical examinations will have an underlying clinically significant finding on imaging [10]; and 2) surveillance, performed periodically with the aid of noninvasive and invasive device-based methods to assess blood access flow rate (Qa), access recirculation, and dialysis venous pressure; c) diagnostic imaging, such as Doppler ultrasound (US) or diagnostic fistulography upon detection or suspicion of an access abnormality [4]. In this document, when it is noted that the entire extremity is imaged or treated, for the upper extremity, this is assumed to cover the shoulder through the hand, and for the lower extremity, this is assumed to cover the hip through the foot. Moreover, when surgical consultation is discussed as an intervention, it connotes consulting or referring a patient to a surgeon, be they vascular or transplant surgeon, in order to assess the patient for the specific clinical presentation in question. This may be in settings where a surgical procedure such as new access creation, access revision, or access ligation is deemed to be a fitting therapy. Fistulography allows for comprehensive imaging evaluation of the entire hemodialysis vascular access and is routinely conducted with iodinated contrast material [13]. Ehrman et al [14] suggests that when using iodinated contrast material as the reference standard, the sensitivity, specificity, and accuracy of carbon dioxide is 94%, 58%, and 75%, respectively. A shortcoming is that carbon dioxide is not as reliable in assessing venous anatomy and may overestimate the extent of a visualized stenosis. In addition, when given intra-arterially, there is a possibility that carbon dioxide may create a vapor lock with resultant transient ischemia or loss of consciousness or other neurologic Dialysis Fistula Malfunction events due to its passing into the cerebral arterial circulation [15,16]. As such, it is not used in retrograde or reflux techniques to image the arterial anastomosis.

Dialysis Fistula Malfunction. As high as 90% of accesses with abnormal physical examinations will have an underlying clinically significant finding on imaging [10]; and 2) surveillance, performed periodically with the aid of noninvasive and invasive device-based methods to assess blood access flow rate (Qa), access recirculation, and dialysis venous pressure; c) diagnostic imaging, such as Doppler ultrasound (US) or diagnostic fistulography upon detection or suspicion of an access abnormality [4]. In this document, when it is noted that the entire extremity is imaged or treated, for the upper extremity, this is assumed to cover the shoulder through the hand, and for the lower extremity, this is assumed to cover the hip through the foot. Moreover, when surgical consultation is discussed as an intervention, it connotes consulting or referring a patient to a surgeon, be they vascular or transplant surgeon, in order to assess the patient for the specific clinical presentation in question. This may be in settings where a surgical procedure such as new access creation, access revision, or access ligation is deemed to be a fitting therapy. Fistulography allows for comprehensive imaging evaluation of the entire hemodialysis vascular access and is routinely conducted with iodinated contrast material [13]. Ehrman et al [14] suggests that when using iodinated contrast material as the reference standard, the sensitivity, specificity, and accuracy of carbon dioxide is 94%, 58%, and 75%, respectively. A shortcoming is that carbon dioxide is not as reliable in assessing venous anatomy and may overestimate the extent of a visualized stenosis. In addition, when given intra-arterially, there is a possibility that carbon dioxide may create a vapor lock with resultant transient ischemia or loss of consciousness or other neurologic Dialysis Fistula Malfunction events due to its passing into the cerebral arterial circulation [15,16]. As such, it is not used in retrograde or reflux techniques to image the arterial anastomosis.

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acrac_3158170_3

Dialysis Fistula Malfunction

While DSA allows for assessing vascular stenoses, most investigators tend towards an antegrade puncture at the distal aspect of the efferent vein for diagnostic fistulography. This necessitates retrograde opacification of the juxta- anastomotic segments to illustrate a possible stenosis. In identifying a stenosis in the proximal inflow segments during DSA, the interventionalist has to achieve retrograde sheath access to facilitate treatment, increasing procedure time [17]. Wasinrat et al [17] reported that DSA posed a limitation in facilitating stenosis detection on 2- D projections in the coronal view. Similarly, Heye et al [18] demonstrated an underestimation of stenoses on DSA when compared to multidetector CT (MDCT) angiography, where a stenosis was viewed in transverse and sagittal planes of planar reconstruction. It should be noted that the European Best Practice Guidelines Expert Group on Hemodialysis recommends against performing diagnostic fistulography without the intention to intervene on significant findings which may be causing the access dysfunction [19]. Diagnostic fistulography is useful for suspected dialysis access dysfunction if there is an intention to perform endovascular intervention on significant findings or if it is needed to support surgical planning [7]. US Duplex Doppler Hemodialysis Access Area of Interest US performed in B-mode and duplex Doppler US settings have sensitivity and specificity comparable to diagnostic fistulography for hemodynamically significant stenoses within the dialysis vascular access circuit. A study by Vardza Raju et al [25] examined the accuracy of the assessment of AVG and AVF using duplex US in comparison to noted findings on angiography in patients with failing vascular accesses in 51 accesses (35 AVF, 16 AVG). They reported that duplex Doppler US had 95.5% sensitivity and 57.1% specificity for stenoses >50% when using a ratio of peak systolic velocities.

Dialysis Fistula Malfunction. While DSA allows for assessing vascular stenoses, most investigators tend towards an antegrade puncture at the distal aspect of the efferent vein for diagnostic fistulography. This necessitates retrograde opacification of the juxta- anastomotic segments to illustrate a possible stenosis. In identifying a stenosis in the proximal inflow segments during DSA, the interventionalist has to achieve retrograde sheath access to facilitate treatment, increasing procedure time [17]. Wasinrat et al [17] reported that DSA posed a limitation in facilitating stenosis detection on 2- D projections in the coronal view. Similarly, Heye et al [18] demonstrated an underestimation of stenoses on DSA when compared to multidetector CT (MDCT) angiography, where a stenosis was viewed in transverse and sagittal planes of planar reconstruction. It should be noted that the European Best Practice Guidelines Expert Group on Hemodialysis recommends against performing diagnostic fistulography without the intention to intervene on significant findings which may be causing the access dysfunction [19]. Diagnostic fistulography is useful for suspected dialysis access dysfunction if there is an intention to perform endovascular intervention on significant findings or if it is needed to support surgical planning [7]. US Duplex Doppler Hemodialysis Access Area of Interest US performed in B-mode and duplex Doppler US settings have sensitivity and specificity comparable to diagnostic fistulography for hemodynamically significant stenoses within the dialysis vascular access circuit. A study by Vardza Raju et al [25] examined the accuracy of the assessment of AVG and AVF using duplex US in comparison to noted findings on angiography in patients with failing vascular accesses in 51 accesses (35 AVF, 16 AVG). They reported that duplex Doppler US had 95.5% sensitivity and 57.1% specificity for stenoses >50% when using a ratio of peak systolic velocities.

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acrac_3158170_4

Dialysis Fistula Malfunction

Measurement of the residual diameter of a stenotic lesion using B-mode US has also been proposed as a method for identifying a stenosis within an AVF or AVG [26]. The measurement of AVF or AVG blood flow by US is not considered as accurate when compared to other methods of measuring blood flow through the dialysis vascular access. Data on duplex Doppler US flow volume assessments suggests that an optimally functioning AVF demonstrates a flow rate of 700 to 1,300 mL/min [27]. Values of <500 mL/min [4] and <300 mL/min [27] serve as predictors of access dysfunction and pending thrombosis, respectively. In addition to such absolute measurements, it has been demonstrated that a vascular access with prior stability of flow volumes >1,000 mL/min followed by a reduction of >25% over a relatively short time interval of 1 to 4 months may predict access dysfunction [28]. Some issues with obtaining diagnostic images with US include limitations related to patient anatomy. Given that systematic assessment of an AVF by duplex US may be challenging, its use is encouraged when monitoring or surveillance has suggested abnormalities or when limitations to performance of routine dialysis arise. Such abnormalities or limitations may be reflected by reports of difficulty cannulating the access for hemodialysis, inadequate blood flows, high venous pressures, or prolonged bleeding after removal of dialysis access needles. While a few studies have shown the feasibility of US-guided angioplasty for the treatment of stenosis, the majority of endovascular treatment is still performed using fluoroscopically-guided fistulography in an angiography suite [29,30]. The use of physical examination findings and other indicators of a dysfunctional dialysis access can be used to identify patients with a probable hemodynamically significant stenosis. These patients can in turn be referred directly for diagnostic fistulography and the needed endovascular intervention [31].

Dialysis Fistula Malfunction. Measurement of the residual diameter of a stenotic lesion using B-mode US has also been proposed as a method for identifying a stenosis within an AVF or AVG [26]. The measurement of AVF or AVG blood flow by US is not considered as accurate when compared to other methods of measuring blood flow through the dialysis vascular access. Data on duplex Doppler US flow volume assessments suggests that an optimally functioning AVF demonstrates a flow rate of 700 to 1,300 mL/min [27]. Values of <500 mL/min [4] and <300 mL/min [27] serve as predictors of access dysfunction and pending thrombosis, respectively. In addition to such absolute measurements, it has been demonstrated that a vascular access with prior stability of flow volumes >1,000 mL/min followed by a reduction of >25% over a relatively short time interval of 1 to 4 months may predict access dysfunction [28]. Some issues with obtaining diagnostic images with US include limitations related to patient anatomy. Given that systematic assessment of an AVF by duplex US may be challenging, its use is encouraged when monitoring or surveillance has suggested abnormalities or when limitations to performance of routine dialysis arise. Such abnormalities or limitations may be reflected by reports of difficulty cannulating the access for hemodialysis, inadequate blood flows, high venous pressures, or prolonged bleeding after removal of dialysis access needles. While a few studies have shown the feasibility of US-guided angioplasty for the treatment of stenosis, the majority of endovascular treatment is still performed using fluoroscopically-guided fistulography in an angiography suite [29,30]. The use of physical examination findings and other indicators of a dysfunctional dialysis access can be used to identify patients with a probable hemodynamically significant stenosis. These patients can in turn be referred directly for diagnostic fistulography and the needed endovascular intervention [31].

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acrac_3158170_5

Dialysis Fistula Malfunction

During fistulography to treat a stenosis, venography may reveal a narrowing that may represent a stenosis or vasospasm. Preprocedural US has the added advantage of differentiating structural stenoses from transient self-limiting vasospasm [32]. Duplex Doppler US can aid monitoring of the response postangioplasty or stenting. The extent of residual stenoses postangioplasty may also be accurately quantified [33]. Dialysis Fistula Malfunction CTA Extremity Area of Interest With IV Contrast CT angiography (CTA) represents an alternative diagnostic study for many peripheral vascular interventions. However, it carries practical and logistical limitations in imaging of dialysis access imaging. Li et al [11] conducted a meta-analysis with the goal of comparing the diagnostic efficacy of CTA and MR angiography (MRA) in the assessment of autologous hemodialysis accesses and the detection of culprit stenoses. Both CTA and MRA were demonstrated to be accurate modalities with sensitivities of 96.2% and 95.4%, specificities of 97.1% and 96.1%, as well as diagnostic odds ratio of 393.69 and 211.47, respectively, in imaging hemodialysis vascular accesses. Even in subgroup and meta-regression analyses, no statistical difference relative to the 2 modalities was demonstrated. As such, there were no statistically significant differences when comparing the diagnostic performance of MRA and CTA in the detection of stenoses within hemodialysis vascular accesses. Both techniques serve as highly accurate alternatives or as trouble-shooting diagnostic complements to conventional DSA. An advantage of MDCT angiography is that it may facilitate 3-D volume data that provides multiple different views that help to overcome the challenge of vessel overlap experienced in DSA [17]. Wasinrat et al [17] reported that DSA posed a limitation in facilitating stenosis detection on 2-D projection in the coronal view.

Dialysis Fistula Malfunction. During fistulography to treat a stenosis, venography may reveal a narrowing that may represent a stenosis or vasospasm. Preprocedural US has the added advantage of differentiating structural stenoses from transient self-limiting vasospasm [32]. Duplex Doppler US can aid monitoring of the response postangioplasty or stenting. The extent of residual stenoses postangioplasty may also be accurately quantified [33]. Dialysis Fistula Malfunction CTA Extremity Area of Interest With IV Contrast CT angiography (CTA) represents an alternative diagnostic study for many peripheral vascular interventions. However, it carries practical and logistical limitations in imaging of dialysis access imaging. Li et al [11] conducted a meta-analysis with the goal of comparing the diagnostic efficacy of CTA and MR angiography (MRA) in the assessment of autologous hemodialysis accesses and the detection of culprit stenoses. Both CTA and MRA were demonstrated to be accurate modalities with sensitivities of 96.2% and 95.4%, specificities of 97.1% and 96.1%, as well as diagnostic odds ratio of 393.69 and 211.47, respectively, in imaging hemodialysis vascular accesses. Even in subgroup and meta-regression analyses, no statistical difference relative to the 2 modalities was demonstrated. As such, there were no statistically significant differences when comparing the diagnostic performance of MRA and CTA in the detection of stenoses within hemodialysis vascular accesses. Both techniques serve as highly accurate alternatives or as trouble-shooting diagnostic complements to conventional DSA. An advantage of MDCT angiography is that it may facilitate 3-D volume data that provides multiple different views that help to overcome the challenge of vessel overlap experienced in DSA [17]. Wasinrat et al [17] reported that DSA posed a limitation in facilitating stenosis detection on 2-D projection in the coronal view.

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acrac_3158170_6

Dialysis Fistula Malfunction

Similarly, Heye et al [18] demonstrated an underestimation of stenoses on DSA when compared to MDCT angiography, where a stenosis was viewed in transverse and sagittal planes of planar reconstruction. CTV Extremity Area of Interest With IV Contrast CT venography (CTV) represents an alternative diagnostic study for many peripheral vascular interventions. However, it carries practical and logistical limitations in dialysis access imaging. There is no relevant literature to support the use of CTV with intravenous (IV) contrast in the evaluation of suspected dysfunction of a hemodialysis access. MRA Extremity Area of Interest Without and With IV Contrast Though not used in practice to visualize an AV access, MRA is a technique that has the potential to visualize the arterial and venous systems using IV contrast material. MRA represents a cross-sectional imaging modality that is noninvasive. It has been utilized for the assessment of vascular access failure, although it is relatively constrained by flow-related artifact, and limited field-of-view. In the meta-analysis by Li et al [11], they reported that MRA was an accurate diagnostic modality with sensitivity of 95.4%, specificity of 96.1%, and diagnostic odds ratio of 211.47, in evaluating hemodialysis AV access. The Li et al [11] meta-analysis of 500 patients with an autologous hemodialysis access, demonstrated that CTA and MRA supported accurate detection of stenoses and comparable diagnostic performance, suggesting that MDCT angiography and MRA may serve as diagnostic technical alternatives to DSA when assessing for stenoses in Dialysis Fistula Malfunction hemodialysis fistulas and grafts. Both CTA and MRA demonstrated high specificity, sensitivity, diagnostic odds ratio, positive likelihood ratio, and negative likelihood ratio with no significant difference in stenosis detection between CTA and MRA.

Dialysis Fistula Malfunction. Similarly, Heye et al [18] demonstrated an underestimation of stenoses on DSA when compared to MDCT angiography, where a stenosis was viewed in transverse and sagittal planes of planar reconstruction. CTV Extremity Area of Interest With IV Contrast CT venography (CTV) represents an alternative diagnostic study for many peripheral vascular interventions. However, it carries practical and logistical limitations in dialysis access imaging. There is no relevant literature to support the use of CTV with intravenous (IV) contrast in the evaluation of suspected dysfunction of a hemodialysis access. MRA Extremity Area of Interest Without and With IV Contrast Though not used in practice to visualize an AV access, MRA is a technique that has the potential to visualize the arterial and venous systems using IV contrast material. MRA represents a cross-sectional imaging modality that is noninvasive. It has been utilized for the assessment of vascular access failure, although it is relatively constrained by flow-related artifact, and limited field-of-view. In the meta-analysis by Li et al [11], they reported that MRA was an accurate diagnostic modality with sensitivity of 95.4%, specificity of 96.1%, and diagnostic odds ratio of 211.47, in evaluating hemodialysis AV access. The Li et al [11] meta-analysis of 500 patients with an autologous hemodialysis access, demonstrated that CTA and MRA supported accurate detection of stenoses and comparable diagnostic performance, suggesting that MDCT angiography and MRA may serve as diagnostic technical alternatives to DSA when assessing for stenoses in Dialysis Fistula Malfunction hemodialysis fistulas and grafts. Both CTA and MRA demonstrated high specificity, sensitivity, diagnostic odds ratio, positive likelihood ratio, and negative likelihood ratio with no significant difference in stenosis detection between CTA and MRA.

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acrac_3158170_7

Dialysis Fistula Malfunction

MRA Extremity Area of Interest Without IV Contrast There is no identified relevant literature to support the use of MRA of the extremity without IV contrast in evaluation of suspected dysfunction of a hemodialysis access. MRV Extremity Area of Interest Without and With IV Contrast There is no identified relevant literature to support the use of MR venography (MRV) of the extremity without and with IV contrast in evaluation of suspected dysfunction of a hemodialysis access. MRV Extremity Area of Interest Without IV Contrast There is no identified relevant literature to support the use of MRV of the extremity without IV contrast in evaluation of suspected dysfunction of a hemodialysis access. Variant 2: Suspected dysfunction of the upper or lower extremity hemodialysis access (ie, arteriovenous fistula or graft) suggested by an abnormal clinical indicator or hemodynamic indicator (ie, reduction in dialysis vascular access blood flow rate or kinetics). Treatment and procedures. Fluoroscopy Fistulography Hemodialysis Access with Intervention Over 90% of dialysis access dysfunction is caused by an anatomic stenosis, which can be identified during diagnostic fistulography [7]. In the setting of a dysfunctional dialysis access, endovascular treatment of a stenosis found during diagnostic fistulography may be warranted. Numerous studies have shown that percutaneous endovascular interventions extend patency rates and reduce the need for surgical revision or abandonment of the dialysis access [22,35-42]. Endovascular interventions have the advantages of being minimally invasive, allowing the procedure to be performed in an outpatient setting. Endovascular interventions are associated with short procedure time, use of moderate sedation as opposed to general anesthesia, and allow for hemodialysis immediately after the procedure. In addition, they can be performed repeatedly without the need for adding graft material or shortening the access [35,38].

Dialysis Fistula Malfunction. MRA Extremity Area of Interest Without IV Contrast There is no identified relevant literature to support the use of MRA of the extremity without IV contrast in evaluation of suspected dysfunction of a hemodialysis access. MRV Extremity Area of Interest Without and With IV Contrast There is no identified relevant literature to support the use of MR venography (MRV) of the extremity without and with IV contrast in evaluation of suspected dysfunction of a hemodialysis access. MRV Extremity Area of Interest Without IV Contrast There is no identified relevant literature to support the use of MRV of the extremity without IV contrast in evaluation of suspected dysfunction of a hemodialysis access. Variant 2: Suspected dysfunction of the upper or lower extremity hemodialysis access (ie, arteriovenous fistula or graft) suggested by an abnormal clinical indicator or hemodynamic indicator (ie, reduction in dialysis vascular access blood flow rate or kinetics). Treatment and procedures. Fluoroscopy Fistulography Hemodialysis Access with Intervention Over 90% of dialysis access dysfunction is caused by an anatomic stenosis, which can be identified during diagnostic fistulography [7]. In the setting of a dysfunctional dialysis access, endovascular treatment of a stenosis found during diagnostic fistulography may be warranted. Numerous studies have shown that percutaneous endovascular interventions extend patency rates and reduce the need for surgical revision or abandonment of the dialysis access [22,35-42]. Endovascular interventions have the advantages of being minimally invasive, allowing the procedure to be performed in an outpatient setting. Endovascular interventions are associated with short procedure time, use of moderate sedation as opposed to general anesthesia, and allow for hemodialysis immediately after the procedure. In addition, they can be performed repeatedly without the need for adding graft material or shortening the access [35,38].

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acrac_3158170_8

Dialysis Fistula Malfunction

The endovascular treatments of dysfunctional dialysis access with a stenotic lesion seen during diagnostic fistulography typically include percutaneous transluminal angioplasty (PTA) using a balloon and stent placement. The 2006 KDOQI guidelines established that PTA represents the first-line treatment for a stenosis in the dialysis access circuit [4]. Technical success for the treatment of a stenosis is defined by the SIR as <30% residual narrowing of the lumen in a treated segment. Clinical success is defined as at least 1 successful session of hemodialysis following treatment [7]. PTA is the first-line endovascular treatment of a hemodynamically significant stenosis [3,7]. Repeated PTA on stenotic lesions can be performed on dialysis access to maintain patency [43]. Technical failure of PTA on a stenotic lesion is associated with loss of AVF patency [44]. An untreated anatomic stenosis within the dialysis access circuit is the leading cause of a thrombosed access. The SIR guidelines suggest that surgical revision should be considered if 2 to 3 interventions are required within a 1-to-3-month period [7]. Clinical success of restoring patency in grafts with hemodynamically significant stenoses without thrombosis that are treated primarily with balloon angioplasty is 85% to 98%. Reported cumulative patency at 6-month (primary), 12-month (primary), and 12-month (secondary) interval was 38% to 63%, 23% to 44%, and 81% to 82%, respectively [45]. In addition to the use of conventional balloons for PTA, high-pressure balloons (>20 atm), cutting balloons, and drug-eluting balloons have been used typically for stenoses resistant to conventional PTA. There has been mixed evidence to support the use of cutting balloons. One prospective randomized study found higher patency rates with cutting balloon angioplasty of venous anastomotic stenoses in a graft compared to conventional angioplasty [46]. However, another prospective randomized study showed no significant change in patency between

Dialysis Fistula Malfunction. The endovascular treatments of dysfunctional dialysis access with a stenotic lesion seen during diagnostic fistulography typically include percutaneous transluminal angioplasty (PTA) using a balloon and stent placement. The 2006 KDOQI guidelines established that PTA represents the first-line treatment for a stenosis in the dialysis access circuit [4]. Technical success for the treatment of a stenosis is defined by the SIR as <30% residual narrowing of the lumen in a treated segment. Clinical success is defined as at least 1 successful session of hemodialysis following treatment [7]. PTA is the first-line endovascular treatment of a hemodynamically significant stenosis [3,7]. Repeated PTA on stenotic lesions can be performed on dialysis access to maintain patency [43]. Technical failure of PTA on a stenotic lesion is associated with loss of AVF patency [44]. An untreated anatomic stenosis within the dialysis access circuit is the leading cause of a thrombosed access. The SIR guidelines suggest that surgical revision should be considered if 2 to 3 interventions are required within a 1-to-3-month period [7]. Clinical success of restoring patency in grafts with hemodynamically significant stenoses without thrombosis that are treated primarily with balloon angioplasty is 85% to 98%. Reported cumulative patency at 6-month (primary), 12-month (primary), and 12-month (secondary) interval was 38% to 63%, 23% to 44%, and 81% to 82%, respectively [45]. In addition to the use of conventional balloons for PTA, high-pressure balloons (>20 atm), cutting balloons, and drug-eluting balloons have been used typically for stenoses resistant to conventional PTA. There has been mixed evidence to support the use of cutting balloons. One prospective randomized study found higher patency rates with cutting balloon angioplasty of venous anastomotic stenoses in a graft compared to conventional angioplasty [46]. However, another prospective randomized study showed no significant change in patency between

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acrac_3158170_9

Dialysis Fistula Malfunction

Dialysis Fistula Malfunction cutting and high-pressure balloon angioplasty, which conflicted with a study by Aftab et al that did show significantly improved patency using cutting balloons compared to high-pressure balloons [47,48]. Drug-eluting balloons coated with paclitaxel have been shown in multiple prospective randomized trials to have significantly improved patency when compared to conventional balloon angioplasty except for a study by Maleux et al that demonstrated higher patency rates but without significance [49-52]. On January 17, 2019, the FDA issued a warning letter about a possible increase in long-term mortality rates among patients with peripheral artery disease treated with paclitaxel-coated balloons and paclitaxel-eluting stents when compared to patients treated with control devices such as noncoated balloons or bare metal stents. The FDA allowed for the continued use of paclitaxel- coated balloons and paclitaxel-eluting stents per the current standard of care with recommendations for continued surveillance and discussion of the risks and benefits with patients, including a possible increased risk of long-term mortality [53]. Indications for placement of an endoluminal stent (bare metal stent or stent graft) as defined by the SIR and KDOQI guidelines, include technical failure of PTA of a culprit lesion, recurrence of the same stenotic lesion within a 3- month period after a prior successful balloon angioplasty, and in the event of a complication during treatment such as venous rupture [3,7]. When indicated, a stent or stent graft can be placed over the stenotic lesion typically following angioplasty. While early studies, such as Quinn et al, did not show significant improvement in patency rates of stents versus PTA, follow-up prospective randomized studies demonstrated a significant improvement in dialysis access patency after bare stent placement [54-57]. Stent grafts have shown superior patency rates when comparing bare stents and angioplasty alone [58-63].

Dialysis Fistula Malfunction. Dialysis Fistula Malfunction cutting and high-pressure balloon angioplasty, which conflicted with a study by Aftab et al that did show significantly improved patency using cutting balloons compared to high-pressure balloons [47,48]. Drug-eluting balloons coated with paclitaxel have been shown in multiple prospective randomized trials to have significantly improved patency when compared to conventional balloon angioplasty except for a study by Maleux et al that demonstrated higher patency rates but without significance [49-52]. On January 17, 2019, the FDA issued a warning letter about a possible increase in long-term mortality rates among patients with peripheral artery disease treated with paclitaxel-coated balloons and paclitaxel-eluting stents when compared to patients treated with control devices such as noncoated balloons or bare metal stents. The FDA allowed for the continued use of paclitaxel- coated balloons and paclitaxel-eluting stents per the current standard of care with recommendations for continued surveillance and discussion of the risks and benefits with patients, including a possible increased risk of long-term mortality [53]. Indications for placement of an endoluminal stent (bare metal stent or stent graft) as defined by the SIR and KDOQI guidelines, include technical failure of PTA of a culprit lesion, recurrence of the same stenotic lesion within a 3- month period after a prior successful balloon angioplasty, and in the event of a complication during treatment such as venous rupture [3,7]. When indicated, a stent or stent graft can be placed over the stenotic lesion typically following angioplasty. While early studies, such as Quinn et al, did not show significant improvement in patency rates of stents versus PTA, follow-up prospective randomized studies demonstrated a significant improvement in dialysis access patency after bare stent placement [54-57]. Stent grafts have shown superior patency rates when comparing bare stents and angioplasty alone [58-63].

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Dialysis Fistula Malfunction

In one multicenter prospective randomized study, Haskal et al [63] demonstrated superior patency rates following the treatment of a stenosis in an AVG using a stent graft versus PTA with patency rates at 12 months of 47.6% versus 24.8% and at 24 months of 26.9% versus 13.5%, respectively. Surgical Consultation Multidisciplinary care in support of the maintenance of hemodialysis access are critical in achieving optimal patient outcomes [64]. According to SIR Quality Improvement Guidelines, endovascular management has emerged as the preferred alternative to open surgery as first-line therapy for dialysis access dysfunction or thrombosis [7]. However, vascular surgery consultation for possible revision or creation of a new fistula should be considered if >2 interventions for dialysis access dysfunction occur within a 3-month period or after a clinical failure of an endovascular treatment [7]. Vascular surgery consultation for access revision may be performed if thrombosis of the access occurs >2 times within a single month, or if recurrence of a correctable stenosis is delineated in the circuit. In patients with recurrent occlusions of their vascular access, hypercoagulability testing ought to be considered [65]. While endovascular interventions are often performed in the setting of suspected stenosis of the vascular access, surgical revision remains a viable option. Multiple nonrandomized prospective and retrospective studies have shown that while surgical revision has significantly higher postintervention primary patency rates when compared to endovascular intervention, repeat endovascular interventions can extend the life of the AVF or AVG [66-71]. Placement of a New Tunneled Dialysis Catheter The KDOQI guidelines suggest that it is preferable for patients requiring hemodialysis to utilize an AV access (AVF or AVG) as opposed to a CVC, whenever possible.

Dialysis Fistula Malfunction. In one multicenter prospective randomized study, Haskal et al [63] demonstrated superior patency rates following the treatment of a stenosis in an AVG using a stent graft versus PTA with patency rates at 12 months of 47.6% versus 24.8% and at 24 months of 26.9% versus 13.5%, respectively. Surgical Consultation Multidisciplinary care in support of the maintenance of hemodialysis access are critical in achieving optimal patient outcomes [64]. According to SIR Quality Improvement Guidelines, endovascular management has emerged as the preferred alternative to open surgery as first-line therapy for dialysis access dysfunction or thrombosis [7]. However, vascular surgery consultation for possible revision or creation of a new fistula should be considered if >2 interventions for dialysis access dysfunction occur within a 3-month period or after a clinical failure of an endovascular treatment [7]. Vascular surgery consultation for access revision may be performed if thrombosis of the access occurs >2 times within a single month, or if recurrence of a correctable stenosis is delineated in the circuit. In patients with recurrent occlusions of their vascular access, hypercoagulability testing ought to be considered [65]. While endovascular interventions are often performed in the setting of suspected stenosis of the vascular access, surgical revision remains a viable option. Multiple nonrandomized prospective and retrospective studies have shown that while surgical revision has significantly higher postintervention primary patency rates when compared to endovascular intervention, repeat endovascular interventions can extend the life of the AVF or AVG [66-71]. Placement of a New Tunneled Dialysis Catheter The KDOQI guidelines suggest that it is preferable for patients requiring hemodialysis to utilize an AV access (AVF or AVG) as opposed to a CVC, whenever possible.

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This is secondary to the association of AV access with reduced vascular access-related events such as infection, thrombotic, and nonthrombotic complications [5]. In special circumstances, a temporary CVC may be required to manage a vascular access complication (<2 weeks). In such cases, a nontunneled CVC or nontunneled dialysis catheter may be used. The KDOQI guidelines considers it reasonable to use a nontunneled internal jugular CVC strictly for temporary purposes for a defined period of time such as <2 weeks or per institutional policy in order to reduce the risk of infection [5]. It is considered prudent to limit the use of such noncuffed, nontunneled dialysis catheters, with special Dialysis Fistula Malfunction consideration for patients requiring emergent access. As such, given the lower infection risk, tunneled CVCs are often used in preference to nontunneled CVCs. In the case of a tunneled dialysis catheter, there is no maximum time limit to CVC use. However, regular evaluation is needed to determine if the CVC offers the most appropriate means for dialysis access.

Dialysis Fistula Malfunction. This is secondary to the association of AV access with reduced vascular access-related events such as infection, thrombotic, and nonthrombotic complications [5]. In special circumstances, a temporary CVC may be required to manage a vascular access complication (<2 weeks). In such cases, a nontunneled CVC or nontunneled dialysis catheter may be used. The KDOQI guidelines considers it reasonable to use a nontunneled internal jugular CVC strictly for temporary purposes for a defined period of time such as <2 weeks or per institutional policy in order to reduce the risk of infection [5]. It is considered prudent to limit the use of such noncuffed, nontunneled dialysis catheters, with special Dialysis Fistula Malfunction consideration for patients requiring emergent access. As such, given the lower infection risk, tunneled CVCs are often used in preference to nontunneled CVCs. In the case of a tunneled dialysis catheter, there is no maximum time limit to CVC use. However, regular evaluation is needed to determine if the CVC offers the most appropriate means for dialysis access.

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Dialysis Fistula Malfunction

Indications for placement of a cuffed, tunneled dialysis catheter include the following: exhaustion of other AV access site options; temporary transition from another form of dialysis (eg, renal transplant-acute rejection, peritoneal dialysis-related complications such as pleural leak); waiting for a live-donor kidney transplant with a scheduled surgical date in <90 days; notably limited life expectancy, <6 to 12 months; medical conditions that are exacerbated by the presence of an AV access such as nontreatable skin lesions at the site of cannulation high-flow with ejection factor <15%, patient scratching the skin over the AV access that is deemed to appreciably increase the risk of infection or access rupture risk; selection by patient after appropriate informed consent such as in the case of competent, >85-year-old elderly patient with needle phobia, high risk for AV access failure, and indeterminate life expectancy [5]. For example, Qa correlates closely with inflow stenoses in AVFs [73]. The KDOQI guidelines recommend AVF intervention when Qa is <450 to 500 mL/min [4]. Also, when the ratio of venous access pressure to the mean arterial pressure is >0.55, this has reflected a reliable predictor for the presence of an outflow stenosis in an AVG [78,79]. The core principle for performing routine vascular access monitoring and surveillance is to detect and treat the stenosis to preempt a reduction in dialysis clearance, to reduce the rate of thrombosis, and to improve AV access function [5]. In one prospective randomized control trial study, 58 AVFs were assessed for subclinical stenosis (>50% reduction in vessel diameter compared with the adjacent segment) and Qa >500 (<900) mL/min but with abnormal physical examination result, and elevated static venous pressure in groups that underwent prophylactic repair by surgery or PTA (pre-emptive intervention group) versus observation.

Dialysis Fistula Malfunction. Indications for placement of a cuffed, tunneled dialysis catheter include the following: exhaustion of other AV access site options; temporary transition from another form of dialysis (eg, renal transplant-acute rejection, peritoneal dialysis-related complications such as pleural leak); waiting for a live-donor kidney transplant with a scheduled surgical date in <90 days; notably limited life expectancy, <6 to 12 months; medical conditions that are exacerbated by the presence of an AV access such as nontreatable skin lesions at the site of cannulation high-flow with ejection factor <15%, patient scratching the skin over the AV access that is deemed to appreciably increase the risk of infection or access rupture risk; selection by patient after appropriate informed consent such as in the case of competent, >85-year-old elderly patient with needle phobia, high risk for AV access failure, and indeterminate life expectancy [5]. For example, Qa correlates closely with inflow stenoses in AVFs [73]. The KDOQI guidelines recommend AVF intervention when Qa is <450 to 500 mL/min [4]. Also, when the ratio of venous access pressure to the mean arterial pressure is >0.55, this has reflected a reliable predictor for the presence of an outflow stenosis in an AVG [78,79]. The core principle for performing routine vascular access monitoring and surveillance is to detect and treat the stenosis to preempt a reduction in dialysis clearance, to reduce the rate of thrombosis, and to improve AV access function [5]. In one prospective randomized control trial study, 58 AVFs were assessed for subclinical stenosis (>50% reduction in vessel diameter compared with the adjacent segment) and Qa >500 (<900) mL/min but with abnormal physical examination result, and elevated static venous pressure in groups that underwent prophylactic repair by surgery or PTA (pre-emptive intervention group) versus observation.

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The loss of AVF was decreased in the group preemptively treated with PTA when compared to the observation alone group, 5 (18%) versus 13 (43%). These correlated to AVF loss rates [event/AVF-year] of 0.066 and 0.186; P = . 041 [5]. US Duplex Doppler Hemodialysis Access Area of Interest Recent evidence supports the safety and efficacy of US-guided interventions for dysfunctional hemodialysis access. Stenotic lesions within the dialysis vascular access circuit can be treated with US-guided balloon angioplasty. In one retrospective study, Wakabayashi et al [80] reported a 97.1% technical and clinical success rate in the US- guided treatment of 4,414 cases of stenosis causing dysfunctional dialysis access. Additional studies report success rates of 92% to 98% for US-guided percutaneous balloon angioplasty of stenoses within the dialysis vascular access circuit [29,30,81]. US-guided interventions allow for such procedures to be performed in an office-based outpatient setting. Major limitations include the difficulty in evaluating for and treating central venous stenoses, lower sensitivity, and specificity of US for the detection of stenotic lesions compared to angiography. While Wakabayashi et al [80] reported identifying and treating central venous stenoses by using a smaller US probe in the intercostal space, the other studies exclude central venous stenosis (CVS). Variant 3: Suspected thrombosis of the upper or lower extremity hemodialysis access, marked by absent pulse and thrill on physical examination. Initial imaging to guide interventional radiologic therapy options. The presence of an occlusive thrombosis reflects a terminal event in the life of a failing AV access. It represents 65% to 85% of all cases of access abandonments. While the precipitating cause of the provocative terminal is often clear, such as venous outflow stenoses or low flow in the case of an AVG, a patient may present with a thrombosis without any obvious mechanism [5,82].

Dialysis Fistula Malfunction. The loss of AVF was decreased in the group preemptively treated with PTA when compared to the observation alone group, 5 (18%) versus 13 (43%). These correlated to AVF loss rates [event/AVF-year] of 0.066 and 0.186; P = . 041 [5]. US Duplex Doppler Hemodialysis Access Area of Interest Recent evidence supports the safety and efficacy of US-guided interventions for dysfunctional hemodialysis access. Stenotic lesions within the dialysis vascular access circuit can be treated with US-guided balloon angioplasty. In one retrospective study, Wakabayashi et al [80] reported a 97.1% technical and clinical success rate in the US- guided treatment of 4,414 cases of stenosis causing dysfunctional dialysis access. Additional studies report success rates of 92% to 98% for US-guided percutaneous balloon angioplasty of stenoses within the dialysis vascular access circuit [29,30,81]. US-guided interventions allow for such procedures to be performed in an office-based outpatient setting. Major limitations include the difficulty in evaluating for and treating central venous stenoses, lower sensitivity, and specificity of US for the detection of stenotic lesions compared to angiography. While Wakabayashi et al [80] reported identifying and treating central venous stenoses by using a smaller US probe in the intercostal space, the other studies exclude central venous stenosis (CVS). Variant 3: Suspected thrombosis of the upper or lower extremity hemodialysis access, marked by absent pulse and thrill on physical examination. Initial imaging to guide interventional radiologic therapy options. The presence of an occlusive thrombosis reflects a terminal event in the life of a failing AV access. It represents 65% to 85% of all cases of access abandonments. While the precipitating cause of the provocative terminal is often clear, such as venous outflow stenoses or low flow in the case of an AVG, a patient may present with a thrombosis without any obvious mechanism [5,82].

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Dialysis Fistula Malfunction Fluoroscopy Fistulography Hemodialysis Access Area of Interest Thrombosis of a hemodialysis vascular access (fistula or graft) connotes lack of blood flow and is a diagnosis that is readily made by physical examination [7]. Diagnostic fistulography is suggested for suspected thrombosis if there is an intention to perform an endovascular intervention on significant findings or if it is needed for surgical planning, according to the SIR Quality Improvement Guidelines [7]. The European Best Practice Guidelines Expert Group on Hemodialysis recommends against performing diagnostic fistulography without intention to intervene on significant findings [19]. Given that up to 90% of dialysis access thrombosis is caused by an underlying stenosis, fistulography performed before or after thrombolysis or thrombectomy can help detect and treat any anatomic stenosis within the dialysis access circuit [7]. US Duplex Doppler Hemodialysis Access Area of Interest There is no known evidence to support the use of diagnostic US once an AVF or AVG is suspected to be thrombosed on physical examination [5,7]. The role of US duplex Doppler has mainly been shown to be beneficial in the identification of stenoses and risk factors for hemodialysis access thrombosis [83]. To prevent adverse outcomes, the KDOQI guidelines suggest routine performance of diagnostic imaging, which includes Doppler US and fistulography when an abnormality is detected [5]. CTA Extremity Area of Interest With IV Contrast MDCT angiography has been shown to correlate well with DSA in evaluation of stenoses in hemodialysis patients with native AVF [17]. MDCT angiography has also been demonstrated to accurately diagnose stenoses in a dysfunctional AVF and AVG with a sensitivity of 95% [84]. In a more recent feasibility study, time-resolved dynamic CTA utilizing 3-phase imaging was compared to Doppler US in the evaluation of AVF and AVG.

Dialysis Fistula Malfunction. Dialysis Fistula Malfunction Fluoroscopy Fistulography Hemodialysis Access Area of Interest Thrombosis of a hemodialysis vascular access (fistula or graft) connotes lack of blood flow and is a diagnosis that is readily made by physical examination [7]. Diagnostic fistulography is suggested for suspected thrombosis if there is an intention to perform an endovascular intervention on significant findings or if it is needed for surgical planning, according to the SIR Quality Improvement Guidelines [7]. The European Best Practice Guidelines Expert Group on Hemodialysis recommends against performing diagnostic fistulography without intention to intervene on significant findings [19]. Given that up to 90% of dialysis access thrombosis is caused by an underlying stenosis, fistulography performed before or after thrombolysis or thrombectomy can help detect and treat any anatomic stenosis within the dialysis access circuit [7]. US Duplex Doppler Hemodialysis Access Area of Interest There is no known evidence to support the use of diagnostic US once an AVF or AVG is suspected to be thrombosed on physical examination [5,7]. The role of US duplex Doppler has mainly been shown to be beneficial in the identification of stenoses and risk factors for hemodialysis access thrombosis [83]. To prevent adverse outcomes, the KDOQI guidelines suggest routine performance of diagnostic imaging, which includes Doppler US and fistulography when an abnormality is detected [5]. CTA Extremity Area of Interest With IV Contrast MDCT angiography has been shown to correlate well with DSA in evaluation of stenoses in hemodialysis patients with native AVF [17]. MDCT angiography has also been demonstrated to accurately diagnose stenoses in a dysfunctional AVF and AVG with a sensitivity of 95% [84]. In a more recent feasibility study, time-resolved dynamic CTA utilizing 3-phase imaging was compared to Doppler US in the evaluation of AVF and AVG.

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In conclusion, dynamic CTA was found to detect multiple pathologic findings not detected by US [85]. While no large studies exist, CTA is frequently performed in practice as a complementary imaging modality to diagnostic US and fistulography. CTV Extremity Area of Interest With IV Contrast There is no relevant literature to support the use of CTV with IV contrast in evaluation of suspected dysfunction of a hemodialysis access. MRA Extremity Area of Interest Area of Interest Without and With IV Contrast There is no relevant literature to support the use of MRA without and with IV contrast in evaluation of suspected dysfunction of a hemodialysis access. MRA Extremity Area of Interest Without IV Contrast Multiple publications provide support for specific noncontrast MRA sequences to evaluate hemodialysis access, for example time-of-flight imaging, black-blood imaging, and quiescent-interval single-shot imaging. However, there is no significant literature to support or recommend its wide-spread usage [86,87]. MRA carries additional disadvantages of flow-related artifacts, as well as artifacts from endoprostheses. MRV Extremity Area of Interest Without and With IV Contrast There is no relevant literature to support the use of MRV without and with IV contrast in evaluation of suspected dysfunction of a hemodialysis access. MRV Extremity Area of Interest Without IV Contrast There is no relevant literature to support the use of MRV without IV contrast in evaluation of suspected dysfunction of a hemodialysis access. Variant 4: Suspected thrombosis of the upper or lower extremity hemodialysis access, marked by absent pulse and thrill on physical examination. Treatment and procedures. Fluoroscopy Fistulography Hemodialysis Access with Intervention Roughly 30% to 60% of AVFs experience thrombosis. Their restoration may be readily achieved using a combination of image-guided percutaneous interventional procedures, surgery, or some permutation of these therapeutic techniques [4].

Dialysis Fistula Malfunction. In conclusion, dynamic CTA was found to detect multiple pathologic findings not detected by US [85]. While no large studies exist, CTA is frequently performed in practice as a complementary imaging modality to diagnostic US and fistulography. CTV Extremity Area of Interest With IV Contrast There is no relevant literature to support the use of CTV with IV contrast in evaluation of suspected dysfunction of a hemodialysis access. MRA Extremity Area of Interest Area of Interest Without and With IV Contrast There is no relevant literature to support the use of MRA without and with IV contrast in evaluation of suspected dysfunction of a hemodialysis access. MRA Extremity Area of Interest Without IV Contrast Multiple publications provide support for specific noncontrast MRA sequences to evaluate hemodialysis access, for example time-of-flight imaging, black-blood imaging, and quiescent-interval single-shot imaging. However, there is no significant literature to support or recommend its wide-spread usage [86,87]. MRA carries additional disadvantages of flow-related artifacts, as well as artifacts from endoprostheses. MRV Extremity Area of Interest Without and With IV Contrast There is no relevant literature to support the use of MRV without and with IV contrast in evaluation of suspected dysfunction of a hemodialysis access. MRV Extremity Area of Interest Without IV Contrast There is no relevant literature to support the use of MRV without IV contrast in evaluation of suspected dysfunction of a hemodialysis access. Variant 4: Suspected thrombosis of the upper or lower extremity hemodialysis access, marked by absent pulse and thrill on physical examination. Treatment and procedures. Fluoroscopy Fistulography Hemodialysis Access with Intervention Roughly 30% to 60% of AVFs experience thrombosis. Their restoration may be readily achieved using a combination of image-guided percutaneous interventional procedures, surgery, or some permutation of these therapeutic techniques [4].

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However, the endovascular therapeutic options have largely superseded open surgical techniques for the restoration of a thrombosed dialysis access [88]. The SIR Standards and Practice Committee guidelines suggest that a stenosis with an associated thrombosis that occurs in a dialysis circuit ought to be managed with endovascular techniques when a perianastomotic stenosis is present and when a concomitant venous stenosis is present. In the former case, when a graft thromboses, such perianastomotic lesions should be managed first with combined thrombolysis and/or thrombectomy as well as balloon angioplasty [7]. Dialysis Fistula Malfunction Surgical Consultation According to the SIR Quality Improvement Guidelines, endovascular management is the preferred alternative to open surgery as a first-line therapy for dialysis accesses thrombosis [7]. However, vascular surgery consultation for possible revision for creation of a new fistula may be considered in the setting of clinical failure of endovascular treatment [7]. Vascular surgery consultation for access revision may be performed if thrombosis of the access occurs >2 times within a single month, or if recurrence of a correctable stenosis is delineated in the circuit. In patients with frequent or recurrent thrombotic occlusions of the hemodialysis access, hypercoagulability testing for associated thrombophilia may also be explored [7,89]. While some 90% of access thromboses are secondary to an anatomic stenosis, it should be noted that alternative precipitating processes exist and include hypotension post hemodialysis, hypercoagulable states, decreased cardiac output, and access site infection [7]. Placement of a New Tunneled Dialysis Catheter In the case of a failed declot of an AVF or AVG, a tunneled dialysis catheter may be performed as an interval means for hemodialysis.

Dialysis Fistula Malfunction. However, the endovascular therapeutic options have largely superseded open surgical techniques for the restoration of a thrombosed dialysis access [88]. The SIR Standards and Practice Committee guidelines suggest that a stenosis with an associated thrombosis that occurs in a dialysis circuit ought to be managed with endovascular techniques when a perianastomotic stenosis is present and when a concomitant venous stenosis is present. In the former case, when a graft thromboses, such perianastomotic lesions should be managed first with combined thrombolysis and/or thrombectomy as well as balloon angioplasty [7]. Dialysis Fistula Malfunction Surgical Consultation According to the SIR Quality Improvement Guidelines, endovascular management is the preferred alternative to open surgery as a first-line therapy for dialysis accesses thrombosis [7]. However, vascular surgery consultation for possible revision for creation of a new fistula may be considered in the setting of clinical failure of endovascular treatment [7]. Vascular surgery consultation for access revision may be performed if thrombosis of the access occurs >2 times within a single month, or if recurrence of a correctable stenosis is delineated in the circuit. In patients with frequent or recurrent thrombotic occlusions of the hemodialysis access, hypercoagulability testing for associated thrombophilia may also be explored [7,89]. While some 90% of access thromboses are secondary to an anatomic stenosis, it should be noted that alternative precipitating processes exist and include hypotension post hemodialysis, hypercoagulable states, decreased cardiac output, and access site infection [7]. Placement of a New Tunneled Dialysis Catheter In the case of a failed declot of an AVF or AVG, a tunneled dialysis catheter may be performed as an interval means for hemodialysis.

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The KDOQI 2019 guidelines suggest that placement of a tunneled (cuffed) dialysis catheter is a valid option, supported by the goal of hemodialysis access use for limited duration (eg, <3 months) [5]. In such cases, when AV access is expected to be ready for use in the short term, it is preferred to place tunneled dialysis catheters in the extremity opposite to the extremity that is anticipated for AV access creation or revision. The KDOQI experts tout that in urgent dialysis initiation (eg, <1 month), a tunneled cuffed femoral CVC may be acceptable until the AV access is created and usable. The option to use the femoral vein allows for preservation of upper extremity vasculature for the pending AV access creation. The KDOQI 2019 guidelines regards it as reasonable to place a tunneled dialysis catheter for a long term or indefinite duration in those with limited life expectancy, patients in whom there are multiple prior failed AV accesses with no available options due to a combination of inflow artery and outflow vein problems (eg, severe arterial occlusive disease, noncorrectable central venous outflow occlusion) or in pediatric patients with vessels of prohibitively diminutive caliber [5]. In addition, tunneled dialysis catheters may be placed for long-term use in patients with a valid preference, whereby use of an AV access would considerably restrict quality of life or attainment of life goals. This is advocated only after the patient has been properly informed of patient-specific risks and benefits of other potential and reasonable access options that specifically apply to them [5].

Dialysis Fistula Malfunction. The KDOQI 2019 guidelines suggest that placement of a tunneled (cuffed) dialysis catheter is a valid option, supported by the goal of hemodialysis access use for limited duration (eg, <3 months) [5]. In such cases, when AV access is expected to be ready for use in the short term, it is preferred to place tunneled dialysis catheters in the extremity opposite to the extremity that is anticipated for AV access creation or revision. The KDOQI experts tout that in urgent dialysis initiation (eg, <1 month), a tunneled cuffed femoral CVC may be acceptable until the AV access is created and usable. The option to use the femoral vein allows for preservation of upper extremity vasculature for the pending AV access creation. The KDOQI 2019 guidelines regards it as reasonable to place a tunneled dialysis catheter for a long term or indefinite duration in those with limited life expectancy, patients in whom there are multiple prior failed AV accesses with no available options due to a combination of inflow artery and outflow vein problems (eg, severe arterial occlusive disease, noncorrectable central venous outflow occlusion) or in pediatric patients with vessels of prohibitively diminutive caliber [5]. In addition, tunneled dialysis catheters may be placed for long-term use in patients with a valid preference, whereby use of an AV access would considerably restrict quality of life or attainment of life goals. This is advocated only after the patient has been properly informed of patient-specific risks and benefits of other potential and reasonable access options that specifically apply to them [5].

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Under valid indications for tunneled dialysis catheter placement, the KDOQI guidelines suggests that when the duration of catheter use is anticipated to be prolonged (>3 months) without the anticipated use of AV access, a tunneled dialysis catheter may be placed in order of preference in the following vein, namely internal jugular, external jugular, femoral, subclavian, and lumbar veins, respectively [5]. In the absence of pathologic findings such as a CVS or devices such as pacemakers, tunneled dialysis catheter placement on the right side is preferred to the left side secondary to a more direct venous anatomy. If a single side demonstrates findings that restrict AV access creation but not catheter placement, that laterality ought to be utilized to preserve the contralateral side for creation of the intended AV access. Dialysis Fistula Malfunction US Duplex Doppler Hemodialysis Access Area of Interest There is minimal data to support US-guided endovascular thrombectomy or thrombolysis [80]. Fluoroscopically- guided endovascular interventions performed during fistulography are routine techniques employed to facilitate endovascular thrombectomy or thrombolysis. Several retrospective studies have shown the feasibility of performing US-guided endovascular thrombectomy or thrombolysis [80,91]. The largest series by Wakabayashi et al [80] reported a 97.4% technical success rate and a 91.9% primary patency rate in 455 cases of US-guided thrombectomy at 1-month. Major limitations include the lower sensitivity and specificity of US for the detection of underlying stenotic lesions compared to angiography. Variant 5: Failure of an upper or lower extremity arteriovenous fistula to mature within 2 months after creation. Initial imaging to guide interventional radiologic therapy options. Optimal hemodialysis is dependent on the presence of a mature, functioning AVF. A mature fistula may be defined as functionally mature or physiologically mature.

Dialysis Fistula Malfunction. Under valid indications for tunneled dialysis catheter placement, the KDOQI guidelines suggests that when the duration of catheter use is anticipated to be prolonged (>3 months) without the anticipated use of AV access, a tunneled dialysis catheter may be placed in order of preference in the following vein, namely internal jugular, external jugular, femoral, subclavian, and lumbar veins, respectively [5]. In the absence of pathologic findings such as a CVS or devices such as pacemakers, tunneled dialysis catheter placement on the right side is preferred to the left side secondary to a more direct venous anatomy. If a single side demonstrates findings that restrict AV access creation but not catheter placement, that laterality ought to be utilized to preserve the contralateral side for creation of the intended AV access. Dialysis Fistula Malfunction US Duplex Doppler Hemodialysis Access Area of Interest There is minimal data to support US-guided endovascular thrombectomy or thrombolysis [80]. Fluoroscopically- guided endovascular interventions performed during fistulography are routine techniques employed to facilitate endovascular thrombectomy or thrombolysis. Several retrospective studies have shown the feasibility of performing US-guided endovascular thrombectomy or thrombolysis [80,91]. The largest series by Wakabayashi et al [80] reported a 97.4% technical success rate and a 91.9% primary patency rate in 455 cases of US-guided thrombectomy at 1-month. Major limitations include the lower sensitivity and specificity of US for the detection of underlying stenotic lesions compared to angiography. Variant 5: Failure of an upper or lower extremity arteriovenous fistula to mature within 2 months after creation. Initial imaging to guide interventional radiologic therapy options. Optimal hemodialysis is dependent on the presence of a mature, functioning AVF. A mature fistula may be defined as functionally mature or physiologically mature.

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The KDOQI guidelines defines a mature fistula as one that dependably provides the prescribed dialysis using 2 needles for greater than two-thirds of the dialysis sessions over a 4 consecutive week period [5]. Fluoroscopy Fistulography Hemodialysis Access Area of Interest Given that early detection and intervention of a nonmaturing AVF can mitigate early access failure, prompt identification is critical. While various noninvasive imaging strategies such as US remain helpful imaging tools for evaluation of a nonmaturing native AVF, fistulography has been often used with other authors citing it as the next step after an initial duplex Doppler US evaluation for suspected nonmaturation [94,95]. Diagnosis of an AVF may be performed via the traditional retrograde venous fistulography or via direct retrograde access of the perfusing brachial artery using a 3F micropuncture access [94]. One of the core benefits of using early fistulography in assessing a native AVF that has been deemed to be nonmaturing is that transvenous angioplasty may be in turn used to correct and achieve functional patency in most cases [96,97]. While the problems in maturation may often be predicted at the time of fistula creation (eg, efferent vein is small, <3 mm), the anatomic location of the principal lesion on angiography has been clearly demonstrated in the anastomosis segment, and juxta-anastomotic segments, with inflow arterial lesions ranging from 4% to 7% of cited studies [95,98]. Multiple reports have cited the benefits of using the percutaneous technique of fistulography to aid early identification of fistulas that are deemed as failing to mature followed by subsequent early treatment of the underlying causes. These subsequent endovascular techniques that may be warranted are readily facilitated and ultimately result in a functional fistula in most patients when this percutaneous imaging and treatment strategy is employed [96,97,99].

Dialysis Fistula Malfunction. The KDOQI guidelines defines a mature fistula as one that dependably provides the prescribed dialysis using 2 needles for greater than two-thirds of the dialysis sessions over a 4 consecutive week period [5]. Fluoroscopy Fistulography Hemodialysis Access Area of Interest Given that early detection and intervention of a nonmaturing AVF can mitigate early access failure, prompt identification is critical. While various noninvasive imaging strategies such as US remain helpful imaging tools for evaluation of a nonmaturing native AVF, fistulography has been often used with other authors citing it as the next step after an initial duplex Doppler US evaluation for suspected nonmaturation [94,95]. Diagnosis of an AVF may be performed via the traditional retrograde venous fistulography or via direct retrograde access of the perfusing brachial artery using a 3F micropuncture access [94]. One of the core benefits of using early fistulography in assessing a native AVF that has been deemed to be nonmaturing is that transvenous angioplasty may be in turn used to correct and achieve functional patency in most cases [96,97]. While the problems in maturation may often be predicted at the time of fistula creation (eg, efferent vein is small, <3 mm), the anatomic location of the principal lesion on angiography has been clearly demonstrated in the anastomosis segment, and juxta-anastomotic segments, with inflow arterial lesions ranging from 4% to 7% of cited studies [95,98]. Multiple reports have cited the benefits of using the percutaneous technique of fistulography to aid early identification of fistulas that are deemed as failing to mature followed by subsequent early treatment of the underlying causes. These subsequent endovascular techniques that may be warranted are readily facilitated and ultimately result in a functional fistula in most patients when this percutaneous imaging and treatment strategy is employed [96,97,99].

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US Duplex Doppler Hemodialysis Access Area of Interest Duplex Doppler US reflects a unique ability to reliably evaluate the functional and structural characteristics of the peripheral vasculature. As such, it has become a well-established imaging modality for vascular access follow-up. Duplex Doppler US reflects a reliable means of assessing the velocity of the flow. KDOQI 2019 guidelines recognize the presence of established minimum US criteria for AVF maturity at 4 weeks that includes evaluation Dialysis Fistula Malfunction of the vessel diameter and flow parameters. Sonographic demonstration of a vessel diameter of 4 to 5 mm and blood flow of 400 to 500 mL/min has been associated with high reliability of the access in providing adequate dialysis [5]. For example, this includes a vein diameter of 6 mm, which is considered adequate. Given the need for a long enough access segment capable of supporting 2 dialysis access needles, a straight segment 10 cm or longer is needed. Finally, demonstration of the depth of the access <6 mm from the skin can also be demonstrated on duplex Doppler US [32]. Doppler US is particularly helpful in assessing the causes of nonmaturation of an AVF, such as the presence of stenoses in the access circuit or competing venous tributaries, and thus can be used to prospectively inform the needed percutaneous or surgical therapy [7]. A vein diameter of at least 5 mm and a palpable thrill are deemed sensitive predictors (83% and 96%, respectively) for successful future dialysis use [100]. Mufty et al [101] suggested that when physical examination, consisting of inspection, palpation, and auscultation was deemed insufficient to support a definitive diagnosis, subsequent diagnostic evaluations first by duplex US followed by angiography may be performed.

Dialysis Fistula Malfunction. US Duplex Doppler Hemodialysis Access Area of Interest Duplex Doppler US reflects a unique ability to reliably evaluate the functional and structural characteristics of the peripheral vasculature. As such, it has become a well-established imaging modality for vascular access follow-up. Duplex Doppler US reflects a reliable means of assessing the velocity of the flow. KDOQI 2019 guidelines recognize the presence of established minimum US criteria for AVF maturity at 4 weeks that includes evaluation Dialysis Fistula Malfunction of the vessel diameter and flow parameters. Sonographic demonstration of a vessel diameter of 4 to 5 mm and blood flow of 400 to 500 mL/min has been associated with high reliability of the access in providing adequate dialysis [5]. For example, this includes a vein diameter of 6 mm, which is considered adequate. Given the need for a long enough access segment capable of supporting 2 dialysis access needles, a straight segment 10 cm or longer is needed. Finally, demonstration of the depth of the access <6 mm from the skin can also be demonstrated on duplex Doppler US [32]. Doppler US is particularly helpful in assessing the causes of nonmaturation of an AVF, such as the presence of stenoses in the access circuit or competing venous tributaries, and thus can be used to prospectively inform the needed percutaneous or surgical therapy [7]. A vein diameter of at least 5 mm and a palpable thrill are deemed sensitive predictors (83% and 96%, respectively) for successful future dialysis use [100]. Mufty et al [101] suggested that when physical examination, consisting of inspection, palpation, and auscultation was deemed insufficient to support a definitive diagnosis, subsequent diagnostic evaluations first by duplex US followed by angiography may be performed.

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In the report of their dedicated surveillance program aimed at optimizing the functional access rate at first dialysis, a functional outcome rate of 94.2% (145/154 patients) at the time of first dialysis or at the end of the studied period was noted. Forty reinterventions were needed secondary to failure to mature in 31 patients (31/40; 77.5%). Thus, an average of 1.29 interventions for every nonmaturing AVF was reported. Reinterventions were required in 9 of 40 (22.5%) of these cases (n = 20) due to dysfunction after there was deemed to be an initial successful maturation. In this cohort, 41.4% of reported reinterventions were required prior to duplex US investigation [101]. Along with flow measurements, direct or derived static pressure, duplex US provides effective surveillance techniques for detection of a nonmaturing AVF in the predialysis stage [102]. Singh et al [103] reported a systematic use of US in triaging immature AVFs and reported an increase in 47% of AVFs that successfully matured to usability by dialysis. CTA Extremity Area of Interest With IV Contrast Contrast-enhanced MDCT angiography may be used to evaluate for anastomotic or juxta-anastomotic strictures, outflow vein stenosis, or dispersal of flow due to an accessory vein in patients with failure of maturation [17,85,104]. CTV Extremity Area of Interest With IV Contrast There is no identified relevant literature to support the use of CTV extremity in evaluating a failure of an AVF to mature. MRA Extremity Area of Interest Without and With IV Contrast There is no identified relevant literature to support the use of MRA extremity without and with IV contrast in evaluating a failure of an AVF to mature. MRA Extremity Area of Interest Without IV Contrast There is no identified relevant literature to support the use of MRA extremity without IV contrast in evaluating a failure of an AVF to mature.

Dialysis Fistula Malfunction. In the report of their dedicated surveillance program aimed at optimizing the functional access rate at first dialysis, a functional outcome rate of 94.2% (145/154 patients) at the time of first dialysis or at the end of the studied period was noted. Forty reinterventions were needed secondary to failure to mature in 31 patients (31/40; 77.5%). Thus, an average of 1.29 interventions for every nonmaturing AVF was reported. Reinterventions were required in 9 of 40 (22.5%) of these cases (n = 20) due to dysfunction after there was deemed to be an initial successful maturation. In this cohort, 41.4% of reported reinterventions were required prior to duplex US investigation [101]. Along with flow measurements, direct or derived static pressure, duplex US provides effective surveillance techniques for detection of a nonmaturing AVF in the predialysis stage [102]. Singh et al [103] reported a systematic use of US in triaging immature AVFs and reported an increase in 47% of AVFs that successfully matured to usability by dialysis. CTA Extremity Area of Interest With IV Contrast Contrast-enhanced MDCT angiography may be used to evaluate for anastomotic or juxta-anastomotic strictures, outflow vein stenosis, or dispersal of flow due to an accessory vein in patients with failure of maturation [17,85,104]. CTV Extremity Area of Interest With IV Contrast There is no identified relevant literature to support the use of CTV extremity in evaluating a failure of an AVF to mature. MRA Extremity Area of Interest Without and With IV Contrast There is no identified relevant literature to support the use of MRA extremity without and with IV contrast in evaluating a failure of an AVF to mature. MRA Extremity Area of Interest Without IV Contrast There is no identified relevant literature to support the use of MRA extremity without IV contrast in evaluating a failure of an AVF to mature.

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MRV Extremity Area of Interest Without and With IV Contrast There is no identified relevant literature to support the use of MRV extremity without and with IV contrast in evaluating a failure of an AVF to mature. MRV Extremity Area of Interest Without IV Contrast There is no identified relevant literature to support the use MRV extremity without IV contrast in evaluating a failure of an AVF to mature. Variant 6: Failure of an upper or lower extremity arteriovenous fistula to mature within 2 months after creation. Treatment and procedures. Fluoroscopy Fistulography Hemodialysis Access with Intervention The SIR Standards and Practice Committee suggests that AVFs that have not met criteria for maturity after 2 months since their creation are candidates for endovascular therapies. These include 3 distinct techniques. Firstly, balloon angioplasty of any afferent preanastomotic stenoses inhibiting arterialization of the AVF may be performed. Secondly, balloon angioplasty of the arterial anastomosis may be performed to augment inflow to the maturing venous segment. Thirdly, any small venous tributaries competing with the main venous outflow by shunting blood flow away from it and thus compromising its maturation may be embolized percutaneously [7]. When performing angioplasty of stenoses within the access circuit that are inhibiting AVF maturation, the maximum acceptable residual stenosis is <30%. Restoration of a palpable thrill posttreatment is the goal in each Dialysis Fistula Malfunction case and is the best predictor of optimal long-term outcomes [105]. Reported clinical success for treatment of nonmaturing AVFs is 92%. In studies using angioplasty as the principal therapeutic percutaneous technique, cumulative patency at 3-month (primary), 6-month (primary), 12-month (primary), 6-month (secondary), and 12- month (secondary) are 71%, 54%, 54%, 82%, and 77%, respectively [7].

Dialysis Fistula Malfunction. MRV Extremity Area of Interest Without and With IV Contrast There is no identified relevant literature to support the use of MRV extremity without and with IV contrast in evaluating a failure of an AVF to mature. MRV Extremity Area of Interest Without IV Contrast There is no identified relevant literature to support the use MRV extremity without IV contrast in evaluating a failure of an AVF to mature. Variant 6: Failure of an upper or lower extremity arteriovenous fistula to mature within 2 months after creation. Treatment and procedures. Fluoroscopy Fistulography Hemodialysis Access with Intervention The SIR Standards and Practice Committee suggests that AVFs that have not met criteria for maturity after 2 months since their creation are candidates for endovascular therapies. These include 3 distinct techniques. Firstly, balloon angioplasty of any afferent preanastomotic stenoses inhibiting arterialization of the AVF may be performed. Secondly, balloon angioplasty of the arterial anastomosis may be performed to augment inflow to the maturing venous segment. Thirdly, any small venous tributaries competing with the main venous outflow by shunting blood flow away from it and thus compromising its maturation may be embolized percutaneously [7]. When performing angioplasty of stenoses within the access circuit that are inhibiting AVF maturation, the maximum acceptable residual stenosis is <30%. Restoration of a palpable thrill posttreatment is the goal in each Dialysis Fistula Malfunction case and is the best predictor of optimal long-term outcomes [105]. Reported clinical success for treatment of nonmaturing AVFs is 92%. In studies using angioplasty as the principal therapeutic percutaneous technique, cumulative patency at 3-month (primary), 6-month (primary), 12-month (primary), 6-month (secondary), and 12- month (secondary) are 71%, 54%, 54%, 82%, and 77%, respectively [7].

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While the long-term viability of fistulas that have been flagged as nonmaturing has been called into question, the early identification of suboptimal maturation and thus the treatment of the AVF may result in a functional fistula in the vast maturity of patients. Two prospective studies demonstrate that immature AVFs may be salvaged by endovascular management in 83% to 87% of cases [95,99]. A study by Clark et al [106] reported a paradigm where native fistulas were assessed with physical examination at 4 to 6 weeks by a surgical or nephrology team member. A single attempt at cannulation was then performed. If the fistula was clearly visible and easily cannulated, no further evaluation was performed, and the fistula continued its subsequent maturation until deemed suitable for use, routinely at 3 months postcreation. If a native fistula was not deemed to have matured sufficiently at 3 months, the patient was referred to interventional radiology for diagnostic fistulography with an attempt at percutaneous salvage. Clark et al [106] reported that percutaneous angioplasty facilitated the salvage of 75 of 85 (88%) of the studied native fistulas that were flagged as failing to mature. They achieved primary patency rates of 45% (6 months) and 34% (12 months). Of note, their reported secondary interventions included angioplasty, stent placement, as well as thrombectomy, which were reported to help augment the patency rate up to 79% at 6 months with long-term rates at 12 months of 75%, and at 18 months to 63% [106]. Surgical Consultation Opinions and research diverge on the causes of nonmaturation. Turmel-Rodrigues et al [97] purports that an AVF that fails to mature is precipitated by a coexisting venous stenosis in 100% of patients assessed with diagnostic fistulography. Conversely, Beathard et al [96] touts that a lack of maturation is routinely due to a competing venous collateral.

Dialysis Fistula Malfunction. While the long-term viability of fistulas that have been flagged as nonmaturing has been called into question, the early identification of suboptimal maturation and thus the treatment of the AVF may result in a functional fistula in the vast maturity of patients. Two prospective studies demonstrate that immature AVFs may be salvaged by endovascular management in 83% to 87% of cases [95,99]. A study by Clark et al [106] reported a paradigm where native fistulas were assessed with physical examination at 4 to 6 weeks by a surgical or nephrology team member. A single attempt at cannulation was then performed. If the fistula was clearly visible and easily cannulated, no further evaluation was performed, and the fistula continued its subsequent maturation until deemed suitable for use, routinely at 3 months postcreation. If a native fistula was not deemed to have matured sufficiently at 3 months, the patient was referred to interventional radiology for diagnostic fistulography with an attempt at percutaneous salvage. Clark et al [106] reported that percutaneous angioplasty facilitated the salvage of 75 of 85 (88%) of the studied native fistulas that were flagged as failing to mature. They achieved primary patency rates of 45% (6 months) and 34% (12 months). Of note, their reported secondary interventions included angioplasty, stent placement, as well as thrombectomy, which were reported to help augment the patency rate up to 79% at 6 months with long-term rates at 12 months of 75%, and at 18 months to 63% [106]. Surgical Consultation Opinions and research diverge on the causes of nonmaturation. Turmel-Rodrigues et al [97] purports that an AVF that fails to mature is precipitated by a coexisting venous stenosis in 100% of patients assessed with diagnostic fistulography. Conversely, Beathard et al [96] touts that a lack of maturation is routinely due to a competing venous collateral.

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Dialysis Fistula Malfunction

Small venous tributaries or accessory veins are thought to shunt blood flow away from the venous outflow, thus impairing maturation. However, the accepted range of etiologies for nonmaturation of an AVF include a stenosis, lack of vein and artery dilation secondary to intimal hyperplasia, the presence of scarring in the outflow vein, and atherosclerotic disease, large accessory veins, an AVF vein that is too deep to cannulate, among other factors [107]. A hemodynamically significant stenosis results in smaller diameters and thus reduced blood flows, a finding which was significant in the Hemodialysis Fistula Maturation (HFM) in their initial studied model [107]. Of note, in this prospective study, there was no significant relationship of fistula nonmaturation with the presence of an accessory vein. However, authors note that a large accessory vein may divert blood flow to a degree that warrants embolization by an interventional radiologist or ligation by a vascular surgeon [103]. In a study by Mufty et al [101] a proactive surveillance program was developed to identify and preemptively manage nonmaturing AVFs. In this study, 164 patients were seen at an outpatient clinic at 2 weeks, 6 weeks, 3 months, 6 months, and 12 months postoperatively, by a dialysis nurse and vascular surgeon. AVF maturation marked in part by patency and functionality were assessed by physical examination as well as US. When there was clinical suspicion for a stenosis, further diagnostic duplex US and/or fistulography was performed. When indicated, a salvage intervention was then performed. Similarly, when a percutaneous salvage procedure was not deemed feasible, creation of a new AVF by the vascular surgeon ensued. Dialysis Fistula Malfunction surgical techniques to facilitate postoperative maturation.

Dialysis Fistula Malfunction. Small venous tributaries or accessory veins are thought to shunt blood flow away from the venous outflow, thus impairing maturation. However, the accepted range of etiologies for nonmaturation of an AVF include a stenosis, lack of vein and artery dilation secondary to intimal hyperplasia, the presence of scarring in the outflow vein, and atherosclerotic disease, large accessory veins, an AVF vein that is too deep to cannulate, among other factors [107]. A hemodynamically significant stenosis results in smaller diameters and thus reduced blood flows, a finding which was significant in the Hemodialysis Fistula Maturation (HFM) in their initial studied model [107]. Of note, in this prospective study, there was no significant relationship of fistula nonmaturation with the presence of an accessory vein. However, authors note that a large accessory vein may divert blood flow to a degree that warrants embolization by an interventional radiologist or ligation by a vascular surgeon [103]. In a study by Mufty et al [101] a proactive surveillance program was developed to identify and preemptively manage nonmaturing AVFs. In this study, 164 patients were seen at an outpatient clinic at 2 weeks, 6 weeks, 3 months, 6 months, and 12 months postoperatively, by a dialysis nurse and vascular surgeon. AVF maturation marked in part by patency and functionality were assessed by physical examination as well as US. When there was clinical suspicion for a stenosis, further diagnostic duplex US and/or fistulography was performed. When indicated, a salvage intervention was then performed. Similarly, when a percutaneous salvage procedure was not deemed feasible, creation of a new AVF by the vascular surgeon ensued. Dialysis Fistula Malfunction surgical techniques to facilitate postoperative maturation.

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Dialysis Fistula Malfunction

They cite that it is reasonable to make an appropriate decision in the setting of a careful individualized approach to a given patient on the use of either endovascular or surgical techniques when the need to intervene on an AV access to promote its maturation postoperatively arises [5]. Placement of a New Tunneled Dialysis Catheter The KDOQI 2019 guidelines regards it as reasonable to place a tunneled dialysis catheter for a short-term duration for patients in whom an AVF or AVG was created but not ready for use and in whom hemodialysis is required [5]. Among the indications for a long-term tunneled dialysis catheter, the KDOQI guidelines considers the following: multiple prior failed AV accesses with no feasible options, a valid patient preference, whereby the use of an AV access may considerably limit quality of life or achievement of stated life goals, after appropriate informed consent of the patient-specific risks and other reasonable and practical access solutions may be afforded to the patient. In addition, the KDOQI guidelines consider it reasonable to place a CVC in patients without any given access creation options due to outflow vein problems, such as a noncorrectable central venous outflow occlusion and/or inflow artery problems such as severe arterial occlusive disease, or in infants/children with prohibitively diminutive vessels. US Duplex Doppler Hemodialysis Access Area of Interest Along with blood flow measurements, direct or derived static pressure, duplex US is among the limited effective surveillance techniques for detection of a nonmaturing AVF in the predialysis stage [102]. Singh et al [103] systematic use of US in triaging immature AVFs resulted in an increase in 47% of AVFs that successfully matured to usability by dialysis. Mufty et al [101] reported the results of a strict but successful surveillance program using a 3-month maturation period required before needling the AVF.

Dialysis Fistula Malfunction. They cite that it is reasonable to make an appropriate decision in the setting of a careful individualized approach to a given patient on the use of either endovascular or surgical techniques when the need to intervene on an AV access to promote its maturation postoperatively arises [5]. Placement of a New Tunneled Dialysis Catheter The KDOQI 2019 guidelines regards it as reasonable to place a tunneled dialysis catheter for a short-term duration for patients in whom an AVF or AVG was created but not ready for use and in whom hemodialysis is required [5]. Among the indications for a long-term tunneled dialysis catheter, the KDOQI guidelines considers the following: multiple prior failed AV accesses with no feasible options, a valid patient preference, whereby the use of an AV access may considerably limit quality of life or achievement of stated life goals, after appropriate informed consent of the patient-specific risks and other reasonable and practical access solutions may be afforded to the patient. In addition, the KDOQI guidelines consider it reasonable to place a CVC in patients without any given access creation options due to outflow vein problems, such as a noncorrectable central venous outflow occlusion and/or inflow artery problems such as severe arterial occlusive disease, or in infants/children with prohibitively diminutive vessels. US Duplex Doppler Hemodialysis Access Area of Interest Along with blood flow measurements, direct or derived static pressure, duplex US is among the limited effective surveillance techniques for detection of a nonmaturing AVF in the predialysis stage [102]. Singh et al [103] systematic use of US in triaging immature AVFs resulted in an increase in 47% of AVFs that successfully matured to usability by dialysis. Mufty et al [101] reported the results of a strict but successful surveillance program using a 3-month maturation period required before needling the AVF.

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Dialysis Fistula Malfunction

Adjuvant duplex US and/or phlebography was offered when physical examination was equivocal. AVF maturation was also confirmed by US and physical examination of the AVF. If indicated; however, a salvage intervention was performed or when a salvage procedure was not possible, a new AVF was created. Duplex US evaluation was also performed to support triaging and screening in 41.4% of reinterventions. Ultimately, with duplex US at the core of the surveillance program, a functional success rate of 94.2% was accomplished [101]. The evidence suggests that the critical role of US is centered in surveillance and flagging of the immature at-risk AVF, diagnostic in determining the cause of failed maturity, or in determining the need for reintervention [100,107,109]. Variant 7: Clinical suspicion of central venous stenosis or occlusion suggested by swelling (ie, soft tissue edema) of the extremity ipsilateral to the upper or lower extremity hemodialysis access, with or without the development of venous collaterals. Initial imaging to guide interventional radiologic therapy options. The presence of an occlusion or hemodynamically significant stenoses in any of the major central or intrathoracic veins, including the internal jugular, subclavian, brachiocephalic veins, or SVC can degrade the function of an AV Dialysis Fistula Malfunction access, resulting in ineffective hemodialysis. These may occur in 5% to 50% of cases. Such lesions may also precipitate high venous pressures secondary to an increase in flow within the AVF, with associated broad symptom severity including chest wall and central ipsilateral extremity venous collaterals, dermatosclerosis, arm edema, ulceration, and SVC syndrome. The presence of such stenoses in the central venous outflow may result in prolonged bleeding after decannulation post dialysis, with or without an increase in venous pressures noted during monitoring of the access or increased AV access recirculation [5].

Dialysis Fistula Malfunction. Adjuvant duplex US and/or phlebography was offered when physical examination was equivocal. AVF maturation was also confirmed by US and physical examination of the AVF. If indicated; however, a salvage intervention was performed or when a salvage procedure was not possible, a new AVF was created. Duplex US evaluation was also performed to support triaging and screening in 41.4% of reinterventions. Ultimately, with duplex US at the core of the surveillance program, a functional success rate of 94.2% was accomplished [101]. The evidence suggests that the critical role of US is centered in surveillance and flagging of the immature at-risk AVF, diagnostic in determining the cause of failed maturity, or in determining the need for reintervention [100,107,109]. Variant 7: Clinical suspicion of central venous stenosis or occlusion suggested by swelling (ie, soft tissue edema) of the extremity ipsilateral to the upper or lower extremity hemodialysis access, with or without the development of venous collaterals. Initial imaging to guide interventional radiologic therapy options. The presence of an occlusion or hemodynamically significant stenoses in any of the major central or intrathoracic veins, including the internal jugular, subclavian, brachiocephalic veins, or SVC can degrade the function of an AV Dialysis Fistula Malfunction access, resulting in ineffective hemodialysis. These may occur in 5% to 50% of cases. Such lesions may also precipitate high venous pressures secondary to an increase in flow within the AVF, with associated broad symptom severity including chest wall and central ipsilateral extremity venous collaterals, dermatosclerosis, arm edema, ulceration, and SVC syndrome. The presence of such stenoses in the central venous outflow may result in prolonged bleeding after decannulation post dialysis, with or without an increase in venous pressures noted during monitoring of the access or increased AV access recirculation [5].

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Dialysis Fistula Malfunction

Causes and exacerbating processes include intravascular CVC, deep venous thromboses, pacemakers and other cardiac rhythm devices, as well as the presence of the hemodialysis AV access itself [4,5]. Fluoroscopy Fistulography Hemodialysis Access Area of Interest There is consensus that central vein occlusions and stenoses that develop in the outflow track of a dialysis access ought to be treated in the setting of handicapping extremity edema [110]. A high index of suspicion, particularly in patients with a history of multiple prior catheter placements or chronic dialysis catheter use, may lead to a clinical diagnosis of CVS. While meticulous physical examination may demonstrate limb or breast swelling and neck or chest wall collaterals, the definitive diagnosis of CVS is made on angiography [111]. Diagnostic fistulography allows for angiographic visualization of a culprit lesion resulting in the noted swelling of the ipsilateral extremity. However, given that a symptomatic CVS is primarily treated with PTA, a single intervention may facilitate both definitive diagnosis of the suspected CVS and its treatment [112]. US Duplex Doppler Hemodialysis Access Area of Interest Duplex US has been cited as suboptimal for the diagnostic assessment of the central veins in part secondary to interference by the enveloping bony thorax as well as due to overlapping soft tissue in obese individuals [111]. However, color flow duplex US negates the need for use of radiocontrast and can also suggest the presence of CVS when there is absent respiratory variation in vessel diameter, a lack of polyphasic atrial waves, and depiction of regional venous collaterals. Data also suggests that duplex US may be used in select patients to identify a culprit CVS requiring an intervention, but also as a means of monitoring the durability of success posttreatment [113].

Dialysis Fistula Malfunction. Causes and exacerbating processes include intravascular CVC, deep venous thromboses, pacemakers and other cardiac rhythm devices, as well as the presence of the hemodialysis AV access itself [4,5]. Fluoroscopy Fistulography Hemodialysis Access Area of Interest There is consensus that central vein occlusions and stenoses that develop in the outflow track of a dialysis access ought to be treated in the setting of handicapping extremity edema [110]. A high index of suspicion, particularly in patients with a history of multiple prior catheter placements or chronic dialysis catheter use, may lead to a clinical diagnosis of CVS. While meticulous physical examination may demonstrate limb or breast swelling and neck or chest wall collaterals, the definitive diagnosis of CVS is made on angiography [111]. Diagnostic fistulography allows for angiographic visualization of a culprit lesion resulting in the noted swelling of the ipsilateral extremity. However, given that a symptomatic CVS is primarily treated with PTA, a single intervention may facilitate both definitive diagnosis of the suspected CVS and its treatment [112]. US Duplex Doppler Hemodialysis Access Area of Interest Duplex US has been cited as suboptimal for the diagnostic assessment of the central veins in part secondary to interference by the enveloping bony thorax as well as due to overlapping soft tissue in obese individuals [111]. However, color flow duplex US negates the need for use of radiocontrast and can also suggest the presence of CVS when there is absent respiratory variation in vessel diameter, a lack of polyphasic atrial waves, and depiction of regional venous collaterals. Data also suggests that duplex US may be used in select patients to identify a culprit CVS requiring an intervention, but also as a means of monitoring the durability of success posttreatment [113].

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Dialysis Fistula Malfunction

For example, in a study comparing duplex US in symptomatic patients with venography as the reference standard, a significant yield with duplex US in addition to 90% agreement with venography was noted. The preferred threshold to detect a >50% stenosis by duplex US was suggested by a poststenotic to prestenotic peak vein velocity ratio of 2.5 [113]. Given the limitations of US in reliably assessing the culprit lesion in the thoracic cavity, there is no relevant literature to support the practical use of duplex Doppler US of the hemodialysis access in evaluation of a suspected CVS or occlusion, suggested by swelling of the extremity ipsilateral to the hemodialysis access. MDCT angiography has been reported to accurately detect stenoses compared to DSA with a sensitivity of 95% (including all segments). However, in a study by Dimopoulou et al [84], the usefulness of MDCT angiography with 3-D image reconstruction was evaluated in the long-term assessment of hemodialysis patients with dysfunctional AVF and AVG. Poor quality of contrast enhancement was noted in 5 (5.5%) of the 92 imaged segments, which were all central in location. This phenomenon was noted in patients with multiple and/or severe stenoses in the AVF or AVG. A pseudostenosis was depicted in the MDCT angiography images in 3 patients secondary to venous compression regional to the thoracic inlet. While this likely occurred due to prone patient positioning with the AVF Dialysis Fistula Malfunction or AVG arm in extended position above the head, similar observations have been made by Heye et al [18] who described 3 pseudostenosis artifacts secondary to venous compression. Conversely, Ko et al [115] reported 100% sensitivity and specificity of MDCT angiography of central venous stenoses with no report of any detected pseudostenosis artifacts regional to the thoracic inlet, nor suboptimal contrast opacification in the central vessels.

Dialysis Fistula Malfunction. For example, in a study comparing duplex US in symptomatic patients with venography as the reference standard, a significant yield with duplex US in addition to 90% agreement with venography was noted. The preferred threshold to detect a >50% stenosis by duplex US was suggested by a poststenotic to prestenotic peak vein velocity ratio of 2.5 [113]. Given the limitations of US in reliably assessing the culprit lesion in the thoracic cavity, there is no relevant literature to support the practical use of duplex Doppler US of the hemodialysis access in evaluation of a suspected CVS or occlusion, suggested by swelling of the extremity ipsilateral to the hemodialysis access. MDCT angiography has been reported to accurately detect stenoses compared to DSA with a sensitivity of 95% (including all segments). However, in a study by Dimopoulou et al [84], the usefulness of MDCT angiography with 3-D image reconstruction was evaluated in the long-term assessment of hemodialysis patients with dysfunctional AVF and AVG. Poor quality of contrast enhancement was noted in 5 (5.5%) of the 92 imaged segments, which were all central in location. This phenomenon was noted in patients with multiple and/or severe stenoses in the AVF or AVG. A pseudostenosis was depicted in the MDCT angiography images in 3 patients secondary to venous compression regional to the thoracic inlet. While this likely occurred due to prone patient positioning with the AVF Dialysis Fistula Malfunction or AVG arm in extended position above the head, similar observations have been made by Heye et al [18] who described 3 pseudostenosis artifacts secondary to venous compression. Conversely, Ko et al [115] reported 100% sensitivity and specificity of MDCT angiography of central venous stenoses with no report of any detected pseudostenosis artifacts regional to the thoracic inlet, nor suboptimal contrast opacification in the central vessels.

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Dialysis Fistula Malfunction

It may be concluded that in cases where MDCT angiography is utilized with inadequate contrast opacification of the central vessels or suspicion for pseudostenosis artifacts, thorough examination of the vascular tree with diagnostic fistulography would be indicated [84]. Additionally, prior review articles support the usage of MDCT for detection of central stenoses [104]. CTV Extremity Area of Interest With IV Contrast The KDOQI 2019 guidelines state that CTV provides the advantage of offering a noninvasive imaging option that allows for concomitant assessment of the four extremities, noting that the relative timing of the IV contrast bolus and the corresponding image acquisition may be challenging [5]. However, there is no identified literature to support the widespread use of CTV extremity with IV contrast in evaluation of suspected central stenosis or occlusion suggested by swelling of the extremity ipsilateral to the hemodialysis access. MRA Extremity Area of Interest Without and With IV Contrast In a meta-analysis by Li et al [11] it was noted that the number of included studies of noncontrast enhanced MRA was not sufficient to support a reliable subgroup analysis. Contrasting to conventional MRA techniques such as time-of-flight and phase-contrast, which depend on phase shift effects or velocity-dependent inflow, the use of gadolinium-enhanced MRA does not rely upon the movement of blood. Unfortunately, in this meta-analysis, the effect could not be explored. Li et al [11] cited that another limitation in MRA lies in the differences in field-of- view between CE-MRA and noncontrast enhanced MRA. The field-of-view of CE-MRA is cited as similar to that of CTA, which includes the complete fistula circuit, namely the inflow artery, arterial anastomosis, draining vein, and central venous outflow to the SVC. However, the field-of-view in noncontrast-enhanced MRA has been reported to exclude imaging of the central venous outflow [11].

Dialysis Fistula Malfunction. It may be concluded that in cases where MDCT angiography is utilized with inadequate contrast opacification of the central vessels or suspicion for pseudostenosis artifacts, thorough examination of the vascular tree with diagnostic fistulography would be indicated [84]. Additionally, prior review articles support the usage of MDCT for detection of central stenoses [104]. CTV Extremity Area of Interest With IV Contrast The KDOQI 2019 guidelines state that CTV provides the advantage of offering a noninvasive imaging option that allows for concomitant assessment of the four extremities, noting that the relative timing of the IV contrast bolus and the corresponding image acquisition may be challenging [5]. However, there is no identified literature to support the widespread use of CTV extremity with IV contrast in evaluation of suspected central stenosis or occlusion suggested by swelling of the extremity ipsilateral to the hemodialysis access. MRA Extremity Area of Interest Without and With IV Contrast In a meta-analysis by Li et al [11] it was noted that the number of included studies of noncontrast enhanced MRA was not sufficient to support a reliable subgroup analysis. Contrasting to conventional MRA techniques such as time-of-flight and phase-contrast, which depend on phase shift effects or velocity-dependent inflow, the use of gadolinium-enhanced MRA does not rely upon the movement of blood. Unfortunately, in this meta-analysis, the effect could not be explored. Li et al [11] cited that another limitation in MRA lies in the differences in field-of- view between CE-MRA and noncontrast enhanced MRA. The field-of-view of CE-MRA is cited as similar to that of CTA, which includes the complete fistula circuit, namely the inflow artery, arterial anastomosis, draining vein, and central venous outflow to the SVC. However, the field-of-view in noncontrast-enhanced MRA has been reported to exclude imaging of the central venous outflow [11].

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Dialysis Fistula Malfunction

Depiction of the central venous outflow is critical as subclavian vein stenoses are not uncommon in patients on hemodialysis. As such, there is no identified relevant literature to support the use of MRA extremity without and with IV contrast in evaluation of suspected central stenosis or occlusion suggested by swelling of the extremity ipsilateral to the hemodialysis access. MRA Extremity Area of Interest Without IV Contrast There is no relevant literature to support the use of MRA extremity without IV contrast in evaluation of suspected central stenosis or occlusion suggested by swelling of the extremity ipsilateral to the hemodialysis access. MRV Extremity Area of Interest Without IV Contrast As the initial imaging to guide interventional radiologic therapy options, there is no identified relevant literature to support the use of MRV extremity without IV contrast in evaluating a patient with clinical suspicion of CVS or occlusion suggested by swelling (ie, soft tissue edema) of the extremity ipsilateral to the upper or lower extremity hemodialysis access, with or without the development of venous collaterals. MRV Extremity Area of Interest Without and With IV Contrast As the initial imaging to guide interventional radiologic therapy options, there is no identified relevant literature to support the use of MRV extremity without and with IV contrast in evaluating a patient with clinical suspicion of CVS or occlusion suggested by swelling (ie, soft tissue edema) of the extremity ipsilateral to the upper or lower extremity hemodialysis access, with or without the development of venous collaterals. Variant 8: Clinical suspicion of central venous stenosis or occlusion suggested by swelling (ie, soft tissue edema) of the extremity ipsilateral to the upper or lower extremity hemodialysis access, with or without the development of venous collaterals. Treatment and procedures.

Dialysis Fistula Malfunction. Depiction of the central venous outflow is critical as subclavian vein stenoses are not uncommon in patients on hemodialysis. As such, there is no identified relevant literature to support the use of MRA extremity without and with IV contrast in evaluation of suspected central stenosis or occlusion suggested by swelling of the extremity ipsilateral to the hemodialysis access. MRA Extremity Area of Interest Without IV Contrast There is no relevant literature to support the use of MRA extremity without IV contrast in evaluation of suspected central stenosis or occlusion suggested by swelling of the extremity ipsilateral to the hemodialysis access. MRV Extremity Area of Interest Without IV Contrast As the initial imaging to guide interventional radiologic therapy options, there is no identified relevant literature to support the use of MRV extremity without IV contrast in evaluating a patient with clinical suspicion of CVS or occlusion suggested by swelling (ie, soft tissue edema) of the extremity ipsilateral to the upper or lower extremity hemodialysis access, with or without the development of venous collaterals. MRV Extremity Area of Interest Without and With IV Contrast As the initial imaging to guide interventional radiologic therapy options, there is no identified relevant literature to support the use of MRV extremity without and with IV contrast in evaluating a patient with clinical suspicion of CVS or occlusion suggested by swelling (ie, soft tissue edema) of the extremity ipsilateral to the upper or lower extremity hemodialysis access, with or without the development of venous collaterals. Variant 8: Clinical suspicion of central venous stenosis or occlusion suggested by swelling (ie, soft tissue edema) of the extremity ipsilateral to the upper or lower extremity hemodialysis access, with or without the development of venous collaterals. Treatment and procedures.

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Fluoroscopy Fistulography Hemodialysis Access with Intervention Employing diagnostic fistulography to support endovascular treatment of a CVS is indicated when a stenosis >50% of the endoluminal diameter is detected, when there is hemodynamic compromise in the dialysis vascular access circuit or when the AVF is nonmaturing. A determination to perform endovascular treatment of central venous stenoses is based on the presence of compelling clinical parameters, which include debilitating arm swelling or the presence of increased frequency of failing accesses [7,116]. Angioplasty for asymptomatic stenoses is not ideal as it is associated with increased progression to symptomatic stenosis [5,110,117]. The KDOQI guidelines 2019 state that an endovascular approach with transluminal balloon Dialysis Fistula Malfunction angioplasty is the first-line treatment of a symptomatic CVS [5,116]. The SIR Standards and Practice Committee guidelines and the KDOQI 2019 guidelines suggest that the use of a stent or stent graft should be considered in the setting of failed angioplasty after employing high-pressure balloons, marked by the presence of a refractory or persistent stenosis, abnormal hemodynamic findings that persist postangioplasty, or elastic venous recoil after angioplasty resulting in a reduction in the normal vessel caliber >50%, or stenosis recurrence within 3 months postangioplasty [5,7]. Yan et al [112] noted that balloon angioplasty of the central venous stenoses were seen to yield little benefit on AV access blood flow but resulted in effective relief of associated symptoms. One retrospective study by Bakken et al [118] reports a primary patency of 76% as equivalent between angioplasty versus angioplasty with stenting at 30 days. 12-month rates of 29% versus 21% for angioplasty and stenting, respectively, were noted.

Dialysis Fistula Malfunction. Fluoroscopy Fistulography Hemodialysis Access with Intervention Employing diagnostic fistulography to support endovascular treatment of a CVS is indicated when a stenosis >50% of the endoluminal diameter is detected, when there is hemodynamic compromise in the dialysis vascular access circuit or when the AVF is nonmaturing. A determination to perform endovascular treatment of central venous stenoses is based on the presence of compelling clinical parameters, which include debilitating arm swelling or the presence of increased frequency of failing accesses [7,116]. Angioplasty for asymptomatic stenoses is not ideal as it is associated with increased progression to symptomatic stenosis [5,110,117]. The KDOQI guidelines 2019 state that an endovascular approach with transluminal balloon Dialysis Fistula Malfunction angioplasty is the first-line treatment of a symptomatic CVS [5,116]. The SIR Standards and Practice Committee guidelines and the KDOQI 2019 guidelines suggest that the use of a stent or stent graft should be considered in the setting of failed angioplasty after employing high-pressure balloons, marked by the presence of a refractory or persistent stenosis, abnormal hemodynamic findings that persist postangioplasty, or elastic venous recoil after angioplasty resulting in a reduction in the normal vessel caliber >50%, or stenosis recurrence within 3 months postangioplasty [5,7]. Yan et al [112] noted that balloon angioplasty of the central venous stenoses were seen to yield little benefit on AV access blood flow but resulted in effective relief of associated symptoms. One retrospective study by Bakken et al [118] reports a primary patency of 76% as equivalent between angioplasty versus angioplasty with stenting at 30 days. 12-month rates of 29% versus 21% for angioplasty and stenting, respectively, were noted.

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In a second retrospective study by Ozyer et al in patients undergoing hemodialysis without CVCs, primary patency, marked by time from intervention to the subsequent intervention, was 24.5 months and 13.4 months, in the angioplasty and stent group, respectively [5,119]. Stents ought to be used cautiously or avoided regional to the thoracic outlet because of the associated risks for extrinsic compression and resultant stent fracture. In addition, the placement of stents over indwelling pacer or defibrillator wires may confound their removal. As such, consideration for their removal or for creation of a new AV access on the contralateral extremity when possible, may be given [5]. Placement of a New Tunneled Dialysis Catheter The presence of an appropriately positioned CVC in the internal jugular vein can result in a CVS even when the duration of placement is brief. Even peripherally inserted central catheters (ie, PICCs) are reported to precipitate a CVS or occlusion in as a high as 7% of cases with subclavian catheters provoking such stenotic lesions in up to 50% of cases [111]. Given that central venous stenoses or occlusions may represent the worst of the CVC-related complications, the KDOQI 2019 guidelines underscore the importance of limiting their use [5]. Considering the limitations of CVCs in precipitating or exacerbating central venous stenoses, there is no relevant literature to support the use of new tunneled dialysis catheter placement in the setting of a suspected CVS or occlusion, suggested by swelling of the extremity ipsilateral to the hemodialysis access. Continued Hemodialysis Access Use with Surveillance Mild symptoms associated with central venous stenoses, or occlusions may improve in time through the development of venous collaterals. As such, the presence of a central venous occlusion or stenosis may be marked by a functional AV access without associated arm edema in some patients [5].

Dialysis Fistula Malfunction. In a second retrospective study by Ozyer et al in patients undergoing hemodialysis without CVCs, primary patency, marked by time from intervention to the subsequent intervention, was 24.5 months and 13.4 months, in the angioplasty and stent group, respectively [5,119]. Stents ought to be used cautiously or avoided regional to the thoracic outlet because of the associated risks for extrinsic compression and resultant stent fracture. In addition, the placement of stents over indwelling pacer or defibrillator wires may confound their removal. As such, consideration for their removal or for creation of a new AV access on the contralateral extremity when possible, may be given [5]. Placement of a New Tunneled Dialysis Catheter The presence of an appropriately positioned CVC in the internal jugular vein can result in a CVS even when the duration of placement is brief. Even peripherally inserted central catheters (ie, PICCs) are reported to precipitate a CVS or occlusion in as a high as 7% of cases with subclavian catheters provoking such stenotic lesions in up to 50% of cases [111]. Given that central venous stenoses or occlusions may represent the worst of the CVC-related complications, the KDOQI 2019 guidelines underscore the importance of limiting their use [5]. Considering the limitations of CVCs in precipitating or exacerbating central venous stenoses, there is no relevant literature to support the use of new tunneled dialysis catheter placement in the setting of a suspected CVS or occlusion, suggested by swelling of the extremity ipsilateral to the hemodialysis access. Continued Hemodialysis Access Use with Surveillance Mild symptoms associated with central venous stenoses, or occlusions may improve in time through the development of venous collaterals. As such, the presence of a central venous occlusion or stenosis may be marked by a functional AV access without associated arm edema in some patients [5].

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Dialysis Fistula Malfunction

In such cases, intervention is unindicated for these asymptomatic lesions or those with minimal associated symptoms [110]. Of note, it is common for a degree of arm edema to occur in patients after AV access construction, possibly related to operative trauma and/or mild venous hypertension. Its postoperative resolution usually occurs in 2 to 6 weeks as the peri-surgical inflammation subsides, and venous collaterals develop. US Duplex Doppler Hemodialysis Access Area of Interest CDUS represents a noninvasive method to evaluate CVS. Limitations include its inadequate use when used to conduct central venous assessments in the absence of an angiographic map. The subclavian and brachiocephalic veins, as well as the SVC are located deep and are thus routinely difficult to visualize on CDUS [17]. Given the limitations of US in reliably assessing the culprit lesion in the thoracic cavity, there is no relevant literature to Dialysis Fistula Malfunction support the use of duplex Doppler US of the hemodialysis access in evaluation of a suspected CVS or occlusion, suggested by swelling of the extremity ipsilateral to the hemodialysis access. Variant 9: Abnormal skin changes associated with the upper or lower extremity hemodialysis access cannulation site, including marked thinning, ulceration, eschar formation, spontaneous bleeding, pseudoaneurysm formation, superficial or deep infection. Initial imaging to guide interventional radiologic therapy options. Fluoroscopy Fistulography Hemodialysis Access Area of Interest In the absence of vascular access site infection, fluoroscopic fistulography of the hemodialysis access may have been considered as an option prior to surgical repair of an aneurysm or pseudoaneurysm to evaluate and treat an underlying venous outflow stenosis that may be a precipitator of the associated aneurysm or pseudoaneurysm [123].

Dialysis Fistula Malfunction. In such cases, intervention is unindicated for these asymptomatic lesions or those with minimal associated symptoms [110]. Of note, it is common for a degree of arm edema to occur in patients after AV access construction, possibly related to operative trauma and/or mild venous hypertension. Its postoperative resolution usually occurs in 2 to 6 weeks as the peri-surgical inflammation subsides, and venous collaterals develop. US Duplex Doppler Hemodialysis Access Area of Interest CDUS represents a noninvasive method to evaluate CVS. Limitations include its inadequate use when used to conduct central venous assessments in the absence of an angiographic map. The subclavian and brachiocephalic veins, as well as the SVC are located deep and are thus routinely difficult to visualize on CDUS [17]. Given the limitations of US in reliably assessing the culprit lesion in the thoracic cavity, there is no relevant literature to Dialysis Fistula Malfunction support the use of duplex Doppler US of the hemodialysis access in evaluation of a suspected CVS or occlusion, suggested by swelling of the extremity ipsilateral to the hemodialysis access. Variant 9: Abnormal skin changes associated with the upper or lower extremity hemodialysis access cannulation site, including marked thinning, ulceration, eschar formation, spontaneous bleeding, pseudoaneurysm formation, superficial or deep infection. Initial imaging to guide interventional radiologic therapy options. Fluoroscopy Fistulography Hemodialysis Access Area of Interest In the absence of vascular access site infection, fluoroscopic fistulography of the hemodialysis access may have been considered as an option prior to surgical repair of an aneurysm or pseudoaneurysm to evaluate and treat an underlying venous outflow stenosis that may be a precipitator of the associated aneurysm or pseudoaneurysm [123].

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Dialysis Fistula Malfunction

Given that the presence of skin erosion or active or impending hemorrhage from an AV access in the setting of a pseudoaneurysm is a surgical emergency, there is no relevant identified literature to support the use of fluoroscopy fistulography in the evaluation of abnormal skin changes associated with the hemodialysis access cannulation site. CTA Extremity Area of Interest With IV Contrast There is no relevant identified literature to support the use of CTA extremity with IV contrast in the evaluation of abnormal skin changes associated with the hemodialysis access cannulation site. CTV Extremity Area of Interest With IV Contrast There is no relevant identified literature to support the use of CTV extremity with IV contrast in the evaluation of abnormal skin changes associated with the hemodialysis access cannulation site. MRA Extremity Area of Interest Without and With IV Contrast There is no relevant identified literature to support the use of MRA extremity without and with IV contrast in the evaluation of abnormal skin changes associated with the hemodialysis access cannulation site. MRA Extremity Area of Interest Without IV Contrast There is no relevant identified literature to support the use of MRA extremity without IV contrast in the evaluation of abnormal skin changes associated with the hemodialysis access cannulation site. MRV Extremity Area of Interest Without and With IV Contrast There is no relevant identified literature to support the use of MRV extremity without and with IV contrast in the evaluation of abnormal skin changes associated with the hemodialysis access cannulation site. MRV Extremity Area of Interest Without IV Contrast There is no relevant literature to support the use of MRV extremity without IV contrast in the evaluation of abnormal skin changes associated with the hemodialysis access cannulation site.

Dialysis Fistula Malfunction. Given that the presence of skin erosion or active or impending hemorrhage from an AV access in the setting of a pseudoaneurysm is a surgical emergency, there is no relevant identified literature to support the use of fluoroscopy fistulography in the evaluation of abnormal skin changes associated with the hemodialysis access cannulation site. CTA Extremity Area of Interest With IV Contrast There is no relevant identified literature to support the use of CTA extremity with IV contrast in the evaluation of abnormal skin changes associated with the hemodialysis access cannulation site. CTV Extremity Area of Interest With IV Contrast There is no relevant identified literature to support the use of CTV extremity with IV contrast in the evaluation of abnormal skin changes associated with the hemodialysis access cannulation site. MRA Extremity Area of Interest Without and With IV Contrast There is no relevant identified literature to support the use of MRA extremity without and with IV contrast in the evaluation of abnormal skin changes associated with the hemodialysis access cannulation site. MRA Extremity Area of Interest Without IV Contrast There is no relevant identified literature to support the use of MRA extremity without IV contrast in the evaluation of abnormal skin changes associated with the hemodialysis access cannulation site. MRV Extremity Area of Interest Without and With IV Contrast There is no relevant identified literature to support the use of MRV extremity without and with IV contrast in the evaluation of abnormal skin changes associated with the hemodialysis access cannulation site. MRV Extremity Area of Interest Without IV Contrast There is no relevant literature to support the use of MRV extremity without IV contrast in the evaluation of abnormal skin changes associated with the hemodialysis access cannulation site.

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Dialysis Fistula Malfunction

Variant 10: Abnormal skin changes associated with the upper or lower extremity hemodialysis access cannulation site, including marked thinning, ulceration, eschar formation, spontaneous bleeding, pseudoaneurysm formation, superficial or deep infection. Treatment and procedures. Fluoroscopy Fistulography Hemodialysis Access with Intervention In cases of suspected superficial or deep infection, there is no evidence to support fluoroscopic fistulography of the hemodialysis access with endovascular intervention. Vascular surgical consultation is supported to evaluate the need for surgical revision. Dialysis Fistula Malfunction In the setting of pseudoaneurysm formation at the hemodialysis access cannulation site without suspicion for infection, fluoroscopic fistulography with endovascular intervention may have a limited role in treatment. There have been several small retrospective and prospective nonrandomized studies suggesting the viability of endovascular treatment of the cannulation site pseudoaneurysms using endovascular stent grafts [124-126]. In a retrospective study of 24 patients with a pseudoaneurysm treated with endovascular stent grafts, Shah et al [124] reported an overall patency rate of 81.5% with a mean follow up of 268.9 days and a treatment failure rate of 18.5%. Of the 5 patients with treatment failure, 3 underwent surgical repair due to graft infection. A retrospective review of 38 endovascular stent placements for treatment of a pseudoaneurysm and stenosis found a complication rate of 28.9%, with a relative risk ratio of 5 for stent graft placement for the treatment of a pseudoaneurysm compared to for a stenosis alone [127]. Fluoroscopic fistulography of the hemodialysis access with endovascular intervention has been considered as an option prior to surgical repair of an aneurysm or pseudoaneurysm to evaluate and treat an underlying venous outflow stenosis that may be a precipitator of the associated aneurysm or pseudoaneurysm [123].

Dialysis Fistula Malfunction. Variant 10: Abnormal skin changes associated with the upper or lower extremity hemodialysis access cannulation site, including marked thinning, ulceration, eschar formation, spontaneous bleeding, pseudoaneurysm formation, superficial or deep infection. Treatment and procedures. Fluoroscopy Fistulography Hemodialysis Access with Intervention In cases of suspected superficial or deep infection, there is no evidence to support fluoroscopic fistulography of the hemodialysis access with endovascular intervention. Vascular surgical consultation is supported to evaluate the need for surgical revision. Dialysis Fistula Malfunction In the setting of pseudoaneurysm formation at the hemodialysis access cannulation site without suspicion for infection, fluoroscopic fistulography with endovascular intervention may have a limited role in treatment. There have been several small retrospective and prospective nonrandomized studies suggesting the viability of endovascular treatment of the cannulation site pseudoaneurysms using endovascular stent grafts [124-126]. In a retrospective study of 24 patients with a pseudoaneurysm treated with endovascular stent grafts, Shah et al [124] reported an overall patency rate of 81.5% with a mean follow up of 268.9 days and a treatment failure rate of 18.5%. Of the 5 patients with treatment failure, 3 underwent surgical repair due to graft infection. A retrospective review of 38 endovascular stent placements for treatment of a pseudoaneurysm and stenosis found a complication rate of 28.9%, with a relative risk ratio of 5 for stent graft placement for the treatment of a pseudoaneurysm compared to for a stenosis alone [127]. Fluoroscopic fistulography of the hemodialysis access with endovascular intervention has been considered as an option prior to surgical repair of an aneurysm or pseudoaneurysm to evaluate and treat an underlying venous outflow stenosis that may be a precipitator of the associated aneurysm or pseudoaneurysm [123].

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Dialysis Fistula Malfunction

In the absence of concomitant infection, this may support an initial diagnostic assessment followed by treatment of any underlying venous outflow or central venous stenoses that may have caused the aneurysm or pseudoaneurysm [123]. Endovascular occlusion of the hemodialysis access using vascular plugs has also been suggested as a potential treatment for patients with aneurysm or pseudoaneurysm formation who are at-risk for rupture and who are poor surgical candidates [128]. Surgical Consultation Surgical management may be helpful in the setting of abnormal skin changes associated with the hemodialysis access cannulation site. Significant risk of life-threatening infection, rupture, and bleeding exists when abnormal skin changes are seen, including marked thinning, ulceration, eschar formation, spontaneous bleeding, pseudoaneurysm formation, superficial, or deep infection [129-132]. The presence of skin erosion or active hemorrhage from an AV access in the setting of a pseudoaneurysm is a surgical emergency that necessitates prompt recognition and definitive management. The treatment of an AVG pseudoaneurysm routinely involves placement of an interposition prosthetic graft which is tunneled in situ or extra-anatomically depending on the presence of a vascular access site infection [5]. Placement of a New Tunneled Dialysis Catheter In the setting of abnormal skin changes associated with the hemodialysis access cannulation site, the placement of a new tunneled dialysis catheter may be indicated as a bridging therapy, allowing for hemodialysis access while the patient undergoes surgical evaluation. If there is clinical concern for a systemic infection or bacteremia, treatment of the underlying infection should be initiated prior to the placement of a new tunneled dialysis catheter. A temporary nontunneled dialysis catheter can be placed for immediate hemodialysis access, while treatment of the infection is initiated.

Dialysis Fistula Malfunction. In the absence of concomitant infection, this may support an initial diagnostic assessment followed by treatment of any underlying venous outflow or central venous stenoses that may have caused the aneurysm or pseudoaneurysm [123]. Endovascular occlusion of the hemodialysis access using vascular plugs has also been suggested as a potential treatment for patients with aneurysm or pseudoaneurysm formation who are at-risk for rupture and who are poor surgical candidates [128]. Surgical Consultation Surgical management may be helpful in the setting of abnormal skin changes associated with the hemodialysis access cannulation site. Significant risk of life-threatening infection, rupture, and bleeding exists when abnormal skin changes are seen, including marked thinning, ulceration, eschar formation, spontaneous bleeding, pseudoaneurysm formation, superficial, or deep infection [129-132]. The presence of skin erosion or active hemorrhage from an AV access in the setting of a pseudoaneurysm is a surgical emergency that necessitates prompt recognition and definitive management. The treatment of an AVG pseudoaneurysm routinely involves placement of an interposition prosthetic graft which is tunneled in situ or extra-anatomically depending on the presence of a vascular access site infection [5]. Placement of a New Tunneled Dialysis Catheter In the setting of abnormal skin changes associated with the hemodialysis access cannulation site, the placement of a new tunneled dialysis catheter may be indicated as a bridging therapy, allowing for hemodialysis access while the patient undergoes surgical evaluation. If there is clinical concern for a systemic infection or bacteremia, treatment of the underlying infection should be initiated prior to the placement of a new tunneled dialysis catheter. A temporary nontunneled dialysis catheter can be placed for immediate hemodialysis access, while treatment of the infection is initiated.

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Dialysis Fistula Malfunction

Given associated increased risks for catheter-associated infection, higher mortality, and lower patency when compared to AVF and AVG, tunneled dialysis catheters should be avoided if possible or considered a temporizing measure until other hemodialysis access is available [108]. Continued Hemodialysis Access Use with Surveillance There is no evidence to support the continued hemodialysis access use with surveillance in the setting of abnormal skin changes associated with the hemodialysis access cannulation site. Surgical evaluation is prompted before continued use of the hemodialysis access, as significant risk of life-threatening infection, rupture, and bleeding exists [129,130]. The prevalence of this entity ranges from 1% to 20% and it occurs secondary to the shunting of arterial blood flow through the AV access and away from the peripheral system [133]. This results in a constellation of signs and Dialysis Fistula Malfunction symptoms, ranging from mild digital (pedal or hand) numbness to severe motor impairment. It may progress to skin ulceration or gangrene necessitating a digit or limb amputation. The physiologic compensatory response to such a phenomenon is augmentation in cardiac output, arterial vasodilation, as well as formation of arterial collaterals. The presence of an arterial inflow stenosis (eg, subclavian artery stenosis) as well as an outflow stenosis (eg, forearm occlusive disease) will worsen these hemodynamics [135]. The syndrome presents more frequently in patients with proximal accesses supported by brachial artery inflow as opposed to distal accesses, such as those with radial artery inflow. It usually manifests as hand pain during as well as while off dialysis and less commonly as loss of function or tissue death. The central objective in treating a patient with hemodialysis presenting with hand ischemia is to preserve the digits and hand without sacrificing the vascular access.

Dialysis Fistula Malfunction. Given associated increased risks for catheter-associated infection, higher mortality, and lower patency when compared to AVF and AVG, tunneled dialysis catheters should be avoided if possible or considered a temporizing measure until other hemodialysis access is available [108]. Continued Hemodialysis Access Use with Surveillance There is no evidence to support the continued hemodialysis access use with surveillance in the setting of abnormal skin changes associated with the hemodialysis access cannulation site. Surgical evaluation is prompted before continued use of the hemodialysis access, as significant risk of life-threatening infection, rupture, and bleeding exists [129,130]. The prevalence of this entity ranges from 1% to 20% and it occurs secondary to the shunting of arterial blood flow through the AV access and away from the peripheral system [133]. This results in a constellation of signs and Dialysis Fistula Malfunction symptoms, ranging from mild digital (pedal or hand) numbness to severe motor impairment. It may progress to skin ulceration or gangrene necessitating a digit or limb amputation. The physiologic compensatory response to such a phenomenon is augmentation in cardiac output, arterial vasodilation, as well as formation of arterial collaterals. The presence of an arterial inflow stenosis (eg, subclavian artery stenosis) as well as an outflow stenosis (eg, forearm occlusive disease) will worsen these hemodynamics [135]. The syndrome presents more frequently in patients with proximal accesses supported by brachial artery inflow as opposed to distal accesses, such as those with radial artery inflow. It usually manifests as hand pain during as well as while off dialysis and less commonly as loss of function or tissue death. The central objective in treating a patient with hemodialysis presenting with hand ischemia is to preserve the digits and hand without sacrificing the vascular access.

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Dialysis Fistula Malfunction

Given that distal hypoperfusion may develop in the absence or presence of arterial stenoses, diagnostic arteriography of the extremity and the entirety of its inflow is a foundational part of the diagnostic evaluation prior to determining management. The subsequent choice of management may only be made after considering this diagnostic study. For example, a concomitant arterial stenosis may have a deleterious effect on a surgical procedure performed to treat the distal ischemia. Failure to recognize such stenoses may prove detrimental postsurgery. For example, in the presence of a hemodynamically significant arterial stenosis that is proximal to the arterial anastomosis of the access, a banding procedure employed to reverse the arterial steal may result in a perilous decline in blood flow through the access, possibly resulting in access thrombosis [133]. Fluoroscopy Fistulography Hemodialysis Access Area of Interest Leon et al [133] describes optimized arteriography as the most critical tool needed to facilitate the diagnosis of DASS or DHIS and support an appropriate treatment strategy. DSA supports effective visualization from the aortic arch to the palmar arch, allowing for detection of lesions in the more proximal arteries. Since steal from the distal vessels may be expected, DSA is performed with and without occlusion of the AV access. While the femoral artery has been used to perform diagnostic fluoroscopic arteriography in this setting, this evaluation may be performed simply by retrograde cannulation of the access with diagnostic catheter advancement into the aortic arch [133]. Given that an arterial stenosis may be an important contributor to distal ischemia, diagnostic fistulography via a percutaneous access has gained popularity in supporting management of DHIS. Valji et al [136] used arteriography to assess patients presenting with clinical findings of hand ischemia. They were able to image the entire arterial tree (ie, aortic arch to the palmar arch).

Dialysis Fistula Malfunction. Given that distal hypoperfusion may develop in the absence or presence of arterial stenoses, diagnostic arteriography of the extremity and the entirety of its inflow is a foundational part of the diagnostic evaluation prior to determining management. The subsequent choice of management may only be made after considering this diagnostic study. For example, a concomitant arterial stenosis may have a deleterious effect on a surgical procedure performed to treat the distal ischemia. Failure to recognize such stenoses may prove detrimental postsurgery. For example, in the presence of a hemodynamically significant arterial stenosis that is proximal to the arterial anastomosis of the access, a banding procedure employed to reverse the arterial steal may result in a perilous decline in blood flow through the access, possibly resulting in access thrombosis [133]. Fluoroscopy Fistulography Hemodialysis Access Area of Interest Leon et al [133] describes optimized arteriography as the most critical tool needed to facilitate the diagnosis of DASS or DHIS and support an appropriate treatment strategy. DSA supports effective visualization from the aortic arch to the palmar arch, allowing for detection of lesions in the more proximal arteries. Since steal from the distal vessels may be expected, DSA is performed with and without occlusion of the AV access. While the femoral artery has been used to perform diagnostic fluoroscopic arteriography in this setting, this evaluation may be performed simply by retrograde cannulation of the access with diagnostic catheter advancement into the aortic arch [133]. Given that an arterial stenosis may be an important contributor to distal ischemia, diagnostic fistulography via a percutaneous access has gained popularity in supporting management of DHIS. Valji et al [136] used arteriography to assess patients presenting with clinical findings of hand ischemia. They were able to image the entire arterial tree (ie, aortic arch to the palmar arch).

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Dialysis Fistula Malfunction

Of those presenting with hand pain, 7 out of 10 patients were found to accurately depict the presence of arterial stenoses. Imaging revealed 3 cases of excessive flow into the access via the arterial anastomosis. To assess for the presence of arterial stenosis in patients with a hemodialysis access who have presented with clinical concern for peripheral ischemia, one study (n = 13) reports using complete arteriography to image from the aortic arch to the palmar arch [136]. They concluded that 62% of the 13 patients who underwent referrals for assessment for steal syndrome were found to have a hemodynamically significant (>50%) arterial stenosis. Another study (n = 5) reveals that a culprit stenosis in the inflow arterial circulation was imaged in 100% of the patients undergoing complete arteriography [137]. Lazarides et al [138] touts that arteriography is not a prerequisite for the diagnosis and management of DHIS. They consider the return of radial or ulnar pulses with associated manual compression of the graft as the sole requisite factor required to confirm the diagnosis. They utilized an empiric threshold level of systolic pressure index <0.5 to denote abnormal nerve conduction studies, marked by a positive predictive value of 75%. In 94% of their studied patients, distal ischemia was detected by a systolic pressure index <0.8 to some degree. In patients with systolic pressure index <0.5, these were most likely to have impaired nerve conduction studies. US Duplex Doppler Hemodialysis Access Area of Interest The changes noted on US examination are not diagnostic of a clinical steal syndrome. However, they can illustrate the presence of a steal phenomenon in settings where DASS or DHIS is clinically suspected. For example, there may be reversal of the blood flow distal to the arterial anastomosis (flow towards the fistula) or it may be Dialysis Fistula Malfunction bidirectional with or without evidence of DASS [139].

Dialysis Fistula Malfunction. Of those presenting with hand pain, 7 out of 10 patients were found to accurately depict the presence of arterial stenoses. Imaging revealed 3 cases of excessive flow into the access via the arterial anastomosis. To assess for the presence of arterial stenosis in patients with a hemodialysis access who have presented with clinical concern for peripheral ischemia, one study (n = 13) reports using complete arteriography to image from the aortic arch to the palmar arch [136]. They concluded that 62% of the 13 patients who underwent referrals for assessment for steal syndrome were found to have a hemodynamically significant (>50%) arterial stenosis. Another study (n = 5) reveals that a culprit stenosis in the inflow arterial circulation was imaged in 100% of the patients undergoing complete arteriography [137]. Lazarides et al [138] touts that arteriography is not a prerequisite for the diagnosis and management of DHIS. They consider the return of radial or ulnar pulses with associated manual compression of the graft as the sole requisite factor required to confirm the diagnosis. They utilized an empiric threshold level of systolic pressure index <0.5 to denote abnormal nerve conduction studies, marked by a positive predictive value of 75%. In 94% of their studied patients, distal ischemia was detected by a systolic pressure index <0.8 to some degree. In patients with systolic pressure index <0.5, these were most likely to have impaired nerve conduction studies. US Duplex Doppler Hemodialysis Access Area of Interest The changes noted on US examination are not diagnostic of a clinical steal syndrome. However, they can illustrate the presence of a steal phenomenon in settings where DASS or DHIS is clinically suspected. For example, there may be reversal of the blood flow distal to the arterial anastomosis (flow towards the fistula) or it may be Dialysis Fistula Malfunction bidirectional with or without evidence of DASS [139].

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Of note, the demonstration of retrograde flow on CDUS evaluation of an AV access does not reliably predict or provide the presence of a clinical steal syndrome. While hemodynamic findings of arterial steal can be illustrated in most patients with forearm as well as proximal AV accesses, development of ischemic symptoms occurs in a small fraction of cases. An array of noninvasive investigations along with duplex US such as digital/brachial index measurements, transcutaneous oxygen saturation, and digital plethysmography may assist in helping to evaluate patients that demonstrate symptoms suggestive of arterial steal [133]. CTA Extremity Area of Interest With IV Contrast While not associated with widespread use in the evaluation of DASS or DHIS, CTA represents a less invasive imaging option for the extremity arteries [133]. MDCT technology has allowed CTA to reliably assess the peripheral arteries in the upper and lower extremities [133]. MDCT is associated with the advantages of high spatial resolution, fast scan times, augmented anatomic coverage, and the capacity for generation of high-quality multiplanar reformats and 3-D renderings from raw data that can be expeditiously reprocessed. CTV Extremity Area of Interest With IV Contrast There is no identifiable relevant literature to support the use of CTV extremity in evaluation of suspected vascular steal. MRA Extremity Area of Interest Without and With IV Contrast Dujim et al [12] reported a study assessing the role of CE-MRA in the evaluation of inflow lesions, where 13 patients were evaluated, of which 2 were referred due to symptoms of steal. In this study, 7 of the 13 patients revealed arterial stenoses while 6 patients demonstrate additional stenoses regional to the shunt and/or outflow. Aside from standard DSA of the shunt and outflow, inflow DSA evaluation was accomplished by catheterization in every case where the CE-MRA exhibited a stenotic inflow lesion.

Dialysis Fistula Malfunction. Of note, the demonstration of retrograde flow on CDUS evaluation of an AV access does not reliably predict or provide the presence of a clinical steal syndrome. While hemodynamic findings of arterial steal can be illustrated in most patients with forearm as well as proximal AV accesses, development of ischemic symptoms occurs in a small fraction of cases. An array of noninvasive investigations along with duplex US such as digital/brachial index measurements, transcutaneous oxygen saturation, and digital plethysmography may assist in helping to evaluate patients that demonstrate symptoms suggestive of arterial steal [133]. CTA Extremity Area of Interest With IV Contrast While not associated with widespread use in the evaluation of DASS or DHIS, CTA represents a less invasive imaging option for the extremity arteries [133]. MDCT technology has allowed CTA to reliably assess the peripheral arteries in the upper and lower extremities [133]. MDCT is associated with the advantages of high spatial resolution, fast scan times, augmented anatomic coverage, and the capacity for generation of high-quality multiplanar reformats and 3-D renderings from raw data that can be expeditiously reprocessed. CTV Extremity Area of Interest With IV Contrast There is no identifiable relevant literature to support the use of CTV extremity in evaluation of suspected vascular steal. MRA Extremity Area of Interest Without and With IV Contrast Dujim et al [12] reported a study assessing the role of CE-MRA in the evaluation of inflow lesions, where 13 patients were evaluated, of which 2 were referred due to symptoms of steal. In this study, 7 of the 13 patients revealed arterial stenoses while 6 patients demonstrate additional stenoses regional to the shunt and/or outflow. Aside from standard DSA of the shunt and outflow, inflow DSA evaluation was accomplished by catheterization in every case where the CE-MRA exhibited a stenotic inflow lesion.

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Endovascular treatment of the culprit stenoses was accomplished after obtaining a confirmatory DSA. In 1 of 2 patients with symptoms of steal, the reported symptoms resolved postangioplasty [12]. MRA Extremity Area of Interest Without IV Contrast There is no identifiable relevant literature to support the use of MRA extremity without IV contrast in evaluation of suspected vascular steal. MRV Extremity Area of Interest Without and With IV Contrast There is no identifiable relevant literature to support the use of MRV extremity without and with IV contrast in evaluation of suspected vascular steal. MRV Extremity Area of Interest Without IV Contrast There is no identifiable relevant literature to support the use of MRV extremity without IV contrast in evaluation of suspected vascular steal. Variant 12: Suspected vascular steal syndrome (upper or lower extremity), suggested by cardiac failure or ischemic symptoms. Treatment and procedures. Fluoroscopy Fistulography Hemodialysis Access with Intervention While surgical management for vascular steal syndrome is often considered, fluoroscopic fistulography of the hemodialysis access with endovascular intervention may have a limited role in treatment, including elimination of a culprit arterial stenosis by angioplasty or stenting. In cases of DASS with stenosis of the inflow artery supplying the hemodialysis access and the extremity, endovascular angioplasty with or without stent placement has been proposed as a potential treatment [140]. Endovascular occlusion of hemodialysis access using vascular plugs has also been suggested as a potential treatment for patients with DASS as an alternative to surgical ligation [128]. In cases where surgical ligation may be challenging due to ulcerations or marked edema or swelling of the extremity, surgery may be delayed due to challenging patient comorbidities [128]. In such cases, an endovascular approach may be necessary to manage the problem.

Dialysis Fistula Malfunction. Endovascular treatment of the culprit stenoses was accomplished after obtaining a confirmatory DSA. In 1 of 2 patients with symptoms of steal, the reported symptoms resolved postangioplasty [12]. MRA Extremity Area of Interest Without IV Contrast There is no identifiable relevant literature to support the use of MRA extremity without IV contrast in evaluation of suspected vascular steal. MRV Extremity Area of Interest Without and With IV Contrast There is no identifiable relevant literature to support the use of MRV extremity without and with IV contrast in evaluation of suspected vascular steal. MRV Extremity Area of Interest Without IV Contrast There is no identifiable relevant literature to support the use of MRV extremity without IV contrast in evaluation of suspected vascular steal. Variant 12: Suspected vascular steal syndrome (upper or lower extremity), suggested by cardiac failure or ischemic symptoms. Treatment and procedures. Fluoroscopy Fistulography Hemodialysis Access with Intervention While surgical management for vascular steal syndrome is often considered, fluoroscopic fistulography of the hemodialysis access with endovascular intervention may have a limited role in treatment, including elimination of a culprit arterial stenosis by angioplasty or stenting. In cases of DASS with stenosis of the inflow artery supplying the hemodialysis access and the extremity, endovascular angioplasty with or without stent placement has been proposed as a potential treatment [140]. Endovascular occlusion of hemodialysis access using vascular plugs has also been suggested as a potential treatment for patients with DASS as an alternative to surgical ligation [128]. In cases where surgical ligation may be challenging due to ulcerations or marked edema or swelling of the extremity, surgery may be delayed due to challenging patient comorbidities [128]. In such cases, an endovascular approach may be necessary to manage the problem.

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Dialysis Fistula Malfunction

Gumus et al [128] reported 21 patients who underwent endovascular occlusion of their native fistulas. Of the studied patients, 2 patients had hyperdynamic heart failure, 2 exhibited DASS and 5 patients had findings of critical hand ischemia with a nonhealing ulcer or necrosis. Successful embolization of all fistulas using AMPLATZER vascular plugs were performed with no immediate or delayed complications with a mean follow-up of 13.5 months. Dialysis Fistula Malfunction In forearm and wrist fistulae, cases of DASS occur at a rate of 1%, and is referred to as palmar arch steal syndrome. While digital revascularization with interval ligation (DRIL) is the most accepted technique with the highest success of correcting signs of steal phenomenon while preserving access patency, it is technically difficult and has a small chance of success when employed in wrist fistulae. This is due to the notably reduced diameter of the associated arteries that may also contain calcific disease in at-risk persons [134]. As such, in forearm AVF, surgical ligation or endovascular embolization of the radial artery distal to the anastomosis are helpful treatment options. Miller et al reported endovascular coil embolization in 10 patients while surgical ligation was conducted in 5 patients. Improvement in symptoms was noted in each of the patients in the endovascular group versus 3 patients in the group which underwent ligation [141]. Advantages of endovascular management include its minimally invasive nature, its ability to be performed concomitantly with diagnostic angiography, and the capacity for performing occlusion of both the distal radial artery as well as any other culprit branches. The ability to perform angioplasty on additional stenoses augments blood flow to the fistula and hand. Endovascular dilation is achievable in the palmar arch arteries and distal forearm where surgical revascularization is routinely not possible.

Dialysis Fistula Malfunction. Gumus et al [128] reported 21 patients who underwent endovascular occlusion of their native fistulas. Of the studied patients, 2 patients had hyperdynamic heart failure, 2 exhibited DASS and 5 patients had findings of critical hand ischemia with a nonhealing ulcer or necrosis. Successful embolization of all fistulas using AMPLATZER vascular plugs were performed with no immediate or delayed complications with a mean follow-up of 13.5 months. Dialysis Fistula Malfunction In forearm and wrist fistulae, cases of DASS occur at a rate of 1%, and is referred to as palmar arch steal syndrome. While digital revascularization with interval ligation (DRIL) is the most accepted technique with the highest success of correcting signs of steal phenomenon while preserving access patency, it is technically difficult and has a small chance of success when employed in wrist fistulae. This is due to the notably reduced diameter of the associated arteries that may also contain calcific disease in at-risk persons [134]. As such, in forearm AVF, surgical ligation or endovascular embolization of the radial artery distal to the anastomosis are helpful treatment options. Miller et al reported endovascular coil embolization in 10 patients while surgical ligation was conducted in 5 patients. Improvement in symptoms was noted in each of the patients in the endovascular group versus 3 patients in the group which underwent ligation [141]. Advantages of endovascular management include its minimally invasive nature, its ability to be performed concomitantly with diagnostic angiography, and the capacity for performing occlusion of both the distal radial artery as well as any other culprit branches. The ability to perform angioplasty on additional stenoses augments blood flow to the fistula and hand. Endovascular dilation is achievable in the palmar arch arteries and distal forearm where surgical revascularization is routinely not possible.

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Dialysis Fistula Malfunction

Distal radial artery embolization combined with recanalization and angioplasty of any present ulnar artery stenoses and occlusions may provide equivalent results with the DRIL operation, which is regarded as the most efficient and effective treatment option for correcting the hemodynamics in DASS. While coil occlusion of the distal radial artery preempts the steal phenomenon in a manner comparable to that of interval ligation, the presence of a normal or effectively angioplastied ulnar artery will offer distal blood flow with superior flows [134]. Surgical Consultation Surgical management in the setting of DASS or ischemic steal syndrome is a useful treatment option [142-146]. Surgical management of moderate-to-severe ischemic steal syndrome may be divided into 3 general categories which includes ligation (banding and plication), rerouting of arterial inflow, and restriction of flow. Surgical techniques for the treatment of DASS include DRIL, which involves ligation of the brachial artery and placement of a vein bypass to the distal brachial artery, revision using distal inflow, distal radial artery ligation, proximalization of arterial inflow, and banding [144,145]. Leake et al [145] evaluation of surgical management of DASS in 175 AV fistulas (80%), 41 upper extremity prosthetic grafts (19%), and 2 thigh grafts (1%) demonstrated that DRIL and ligation were offered to patients with the highest severity of symptoms. When compared to ligation, DRIL is equivalent in symptom resolution, with no associated increase in complications, and offers fistula preservation. When compared to banding, DRIL achieved a higher degree of fistula preservation and with a lower incidence of complications. They concluded that DRIL ought to be the preferred surgical management of DASS in patients with a functioning autologous fistula who are surgical candidates. Gupta et al [147] similarly reported their analysis of the outcomes of management of patients with ischemic steal syndrome.

Dialysis Fistula Malfunction. Distal radial artery embolization combined with recanalization and angioplasty of any present ulnar artery stenoses and occlusions may provide equivalent results with the DRIL operation, which is regarded as the most efficient and effective treatment option for correcting the hemodynamics in DASS. While coil occlusion of the distal radial artery preempts the steal phenomenon in a manner comparable to that of interval ligation, the presence of a normal or effectively angioplastied ulnar artery will offer distal blood flow with superior flows [134]. Surgical Consultation Surgical management in the setting of DASS or ischemic steal syndrome is a useful treatment option [142-146]. Surgical management of moderate-to-severe ischemic steal syndrome may be divided into 3 general categories which includes ligation (banding and plication), rerouting of arterial inflow, and restriction of flow. Surgical techniques for the treatment of DASS include DRIL, which involves ligation of the brachial artery and placement of a vein bypass to the distal brachial artery, revision using distal inflow, distal radial artery ligation, proximalization of arterial inflow, and banding [144,145]. Leake et al [145] evaluation of surgical management of DASS in 175 AV fistulas (80%), 41 upper extremity prosthetic grafts (19%), and 2 thigh grafts (1%) demonstrated that DRIL and ligation were offered to patients with the highest severity of symptoms. When compared to ligation, DRIL is equivalent in symptom resolution, with no associated increase in complications, and offers fistula preservation. When compared to banding, DRIL achieved a higher degree of fistula preservation and with a lower incidence of complications. They concluded that DRIL ought to be the preferred surgical management of DASS in patients with a functioning autologous fistula who are surgical candidates. Gupta et al [147] similarly reported their analysis of the outcomes of management of patients with ischemic steal syndrome.

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acrac_3097049_0

Imaging After Shoulder Arthroplasty PCAs

Introduction/Background There has been a rapid increase in the number of shoulder arthroplasties, including partial or complete humeral head resurfacing, hemiarthroplasty, total shoulder arthroplasty, and reverse total shoulder arthroplasty, performed in the United States over the past 2 decades [1]. The most recent published estimates have reported a 2.5-fold increase in the number of shoulder arthroplasties performed between 1998 and 2008, from 19,000 to 47,000 [1,2]. Overall, total shoulder arthroplasties are the most common type, having surpassed hemiarthroplasties in the last decade [1]. Most shoulder arthroplasties are performed for degenerative conditions. Humeral head resurfacing is indicated in patients with humeral head osteonecrosis, large Hill-Sachs deformity, or focal osteoarthrosis. Hemiarthroplasties are typically performed in patients with osteoarthrosis limited to the humeral head or in patients with comminuted humeral head fractures. Hemiarthroplasties are also recommended in patients with deficient glenoid bone stock and in patients with greater preoperative comorbidities because they require a shorter intraoperative time compared with total shoulder arthroplasty. Presently, total shoulder arthroplasty is recommended over hemiarthroplasty for advanced shoulder osteoarthrosis because of its superior clinical outcome. Reverse shoulder arthroplasties were first introduced in 1987 as a treatment option for patients with a deficient rotator cuff and have been used as a salvage procedure for patients with failed total shoulder arthroplasties [3,4]. Reverse shoulder arthroplasties are constructed differently from total shoulder arthroplasties to compensate for the lack of stabilization related to the deficient rotator cuff. The glenoid component is a round metal ball (referred to as the glenosphere) attached to a baseplate along the glenoid surface, and the humeral component has a cup-shaped articular margin secured by a metal stem [4].

Imaging After Shoulder Arthroplasty PCAs. Introduction/Background There has been a rapid increase in the number of shoulder arthroplasties, including partial or complete humeral head resurfacing, hemiarthroplasty, total shoulder arthroplasty, and reverse total shoulder arthroplasty, performed in the United States over the past 2 decades [1]. The most recent published estimates have reported a 2.5-fold increase in the number of shoulder arthroplasties performed between 1998 and 2008, from 19,000 to 47,000 [1,2]. Overall, total shoulder arthroplasties are the most common type, having surpassed hemiarthroplasties in the last decade [1]. Most shoulder arthroplasties are performed for degenerative conditions. Humeral head resurfacing is indicated in patients with humeral head osteonecrosis, large Hill-Sachs deformity, or focal osteoarthrosis. Hemiarthroplasties are typically performed in patients with osteoarthrosis limited to the humeral head or in patients with comminuted humeral head fractures. Hemiarthroplasties are also recommended in patients with deficient glenoid bone stock and in patients with greater preoperative comorbidities because they require a shorter intraoperative time compared with total shoulder arthroplasty. Presently, total shoulder arthroplasty is recommended over hemiarthroplasty for advanced shoulder osteoarthrosis because of its superior clinical outcome. Reverse shoulder arthroplasties were first introduced in 1987 as a treatment option for patients with a deficient rotator cuff and have been used as a salvage procedure for patients with failed total shoulder arthroplasties [3,4]. Reverse shoulder arthroplasties are constructed differently from total shoulder arthroplasties to compensate for the lack of stabilization related to the deficient rotator cuff. The glenoid component is a round metal ball (referred to as the glenosphere) attached to a baseplate along the glenoid surface, and the humeral component has a cup-shaped articular margin secured by a metal stem [4].

3097049

acrac_3097049_1

Imaging After Shoulder Arthroplasty PCAs

The construct moves the center of rotation medial and distal, which allows the deltoid muscle to serve as a main stabilizer of the arthroplasty and joint [4]. Additionally, the more medial and distal center of rotation decreases the risk of glenoid loosening [4,5]. Symptoms related to postoperative difficulties include activity-related pain, decreased range of motion, and apprehension. Some patients report immediate and persistent dissatisfaction, although others report a symptom-free postoperative period followed by increasing pain and decreasing shoulder function and mobility [10]. Imaging can play an important role in diagnosing postoperative complications of shoulder arthroplasties. The imaging algorithm should always begin with an assessment of the hardware components, alignment, and avRad, Eden Prairie, Minnesota. bUT Health San Antonio, San Antonio, Texas. cPanel Chair, Mayo Clinic Arizona, Phoenix, Arizona. dJames J. Peters VA Medical Center, Bronx, New York; American Academy of Orthopaedic Surgeons. eHospital for Special Surgery, New York, New York. fThomas Jefferson University Hospital, Philadelphia, Pennsylvania. gUniversity of Virginia Health System, Charlottesville, Virginia. hDuke University Medical Center, Durham, North Carolina. iUniversity of Missouri Health Care, Columbia, Missouri. jCleveland Clinic, Cleveland, Ohio. kNorthwestern Memorial Hospital, Chicago, Illinois; American College of Physicians. lPenn State Milton S. Hershey Medical Center, Hershey, Pennsylvania and Uniformed Services University of the Health Sciences, Bethesda, Maryland. mThe Ohio State University Wexner Medical Center, Columbus, Ohio. nSpecialty Chair, Mayo Clinic, Phoenix, Arizona. The American College of Radiology seeks and encourages collaboration with other organizations on the development of the ACR Appropriateness Criteria through representation of such organizations on expert panels.

Imaging After Shoulder Arthroplasty PCAs. The construct moves the center of rotation medial and distal, which allows the deltoid muscle to serve as a main stabilizer of the arthroplasty and joint [4]. Additionally, the more medial and distal center of rotation decreases the risk of glenoid loosening [4,5]. Symptoms related to postoperative difficulties include activity-related pain, decreased range of motion, and apprehension. Some patients report immediate and persistent dissatisfaction, although others report a symptom-free postoperative period followed by increasing pain and decreasing shoulder function and mobility [10]. Imaging can play an important role in diagnosing postoperative complications of shoulder arthroplasties. The imaging algorithm should always begin with an assessment of the hardware components, alignment, and avRad, Eden Prairie, Minnesota. bUT Health San Antonio, San Antonio, Texas. cPanel Chair, Mayo Clinic Arizona, Phoenix, Arizona. dJames J. Peters VA Medical Center, Bronx, New York; American Academy of Orthopaedic Surgeons. eHospital for Special Surgery, New York, New York. fThomas Jefferson University Hospital, Philadelphia, Pennsylvania. gUniversity of Virginia Health System, Charlottesville, Virginia. hDuke University Medical Center, Durham, North Carolina. iUniversity of Missouri Health Care, Columbia, Missouri. jCleveland Clinic, Cleveland, Ohio. kNorthwestern Memorial Hospital, Chicago, Illinois; American College of Physicians. lPenn State Milton S. Hershey Medical Center, Hershey, Pennsylvania and Uniformed Services University of the Health Sciences, Bethesda, Maryland. mThe Ohio State University Wexner Medical Center, Columbus, Ohio. nSpecialty Chair, Mayo Clinic, Phoenix, Arizona. The American College of Radiology seeks and encourages collaboration with other organizations on the development of the ACR Appropriateness Criteria through representation of such organizations on expert panels.

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Imaging After Shoulder Arthroplasty PCAs

Participation on the expert panel does not necessarily imply endorsement of the final document by individual contributors or their respective organization. Reprint requests to: publications@acr.org Imaging After Shoulder Arthroplasty surrounding osseous and soft-tissue structures. The selection of the next imaging modality depends on several factors, including findings on the initial imaging study, clinical suspicion of an osseous versus soft-tissue injury, or clinical suspicion of infection. Special Imaging Considerations Arthrography Arthrography, using only radiographic or fluoroscopic images, had previously been utilized for detecting rotator cuff tears in the setting of shoulder arthroplasty. Because of its inability to assess muscle quality, gradation of partial tearing, and differentiate between the torn rotator cuff tendons, conventional radiographic arthrography has mostly been supplanted by cross-sectional imaging techniques such as CT arthrography, MR arthrography, and ultrasound (US). Nuclear Medicine The use of nuclear medicine in the evaluation of complications after arthroplasty has been limited to the evaluation of hip and knee arthroplasties. Because of limited literature on shoulder arthroplasties, these same physiologic principles can be applied to shoulder arthroplasties, and radionuclide imaging is not limited by metallic hardware [11]. Tc-99m-methylene diphosphonate (MDP) bone scans are useful in assessing shoulder arthroplasties, especially with normal radiographs and persistent concern for aseptic loosening, osteomyelitis, or periprosthetic fractures. Unfortunately, the specificity of bone scans is low, and new bone formation can also be seen in normal or abnormal postoperative bony remodeling and neuropathic arthropathy in addition to acute fractures, periprosthetic infection, or aseptic prosthetic loosening. Typical bone scans are either a single or a 3-phase study.

Imaging After Shoulder Arthroplasty PCAs. Participation on the expert panel does not necessarily imply endorsement of the final document by individual contributors or their respective organization. Reprint requests to: publications@acr.org Imaging After Shoulder Arthroplasty surrounding osseous and soft-tissue structures. The selection of the next imaging modality depends on several factors, including findings on the initial imaging study, clinical suspicion of an osseous versus soft-tissue injury, or clinical suspicion of infection. Special Imaging Considerations Arthrography Arthrography, using only radiographic or fluoroscopic images, had previously been utilized for detecting rotator cuff tears in the setting of shoulder arthroplasty. Because of its inability to assess muscle quality, gradation of partial tearing, and differentiate between the torn rotator cuff tendons, conventional radiographic arthrography has mostly been supplanted by cross-sectional imaging techniques such as CT arthrography, MR arthrography, and ultrasound (US). Nuclear Medicine The use of nuclear medicine in the evaluation of complications after arthroplasty has been limited to the evaluation of hip and knee arthroplasties. Because of limited literature on shoulder arthroplasties, these same physiologic principles can be applied to shoulder arthroplasties, and radionuclide imaging is not limited by metallic hardware [11]. Tc-99m-methylene diphosphonate (MDP) bone scans are useful in assessing shoulder arthroplasties, especially with normal radiographs and persistent concern for aseptic loosening, osteomyelitis, or periprosthetic fractures. Unfortunately, the specificity of bone scans is low, and new bone formation can also be seen in normal or abnormal postoperative bony remodeling and neuropathic arthropathy in addition to acute fractures, periprosthetic infection, or aseptic prosthetic loosening. Typical bone scans are either a single or a 3-phase study.

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acrac_3097049_3

Imaging After Shoulder Arthroplasty PCAs

The standard single-phase bone scan involves imaging 2 to 3 hours after MDP administration. The 3-phase bone scan consists of a 1-minute radionuclide angiogram followed by immediate blood pool images and 2- to 3-hour delayed views. The 3-phase scan can be helpful in the assessment of acute fracture and differentiating acute osteomyelitis from cellulitis. A positive 3-phase bone scan is often seen in neuropathic arthropathy. The use of radiolabeled white blood cells (WBC) with In-111 in conjunction with bone marrow imaging, utilizing Tc-99m sulfur colloid, can help to differentiate neuropathic reactive bone marrow from acute osteomyelitis. Serial bone scans can also assist in assessing postoperative bone remodeling and periprosthetic fracture from aseptic periprosthetic loosening. The value of WBC and marrow imaging is not only to differentiate neuropathic arthropathy from acute osteomyelitis but also to differentiate aseptic loosening from acute osteomyelitis. Like neuropathic arthropathy, aseptic loosening will demonstrate spatially congruent WBC and marrow activity, consistent with reactive or hematopoietically active marrow. Imaging After Shoulder Arthroplasty Discussion of Procedures by Variant Variant 1: Routine follow-up of the asymptomatic patient with a primary shoulder arthroplasty. 3-Phase Bone Scan with SPECT or SPECT/CT Shoulder A 3-phase bone scan is not typically ordered for evaluation of the asymptomatic patient. Although, single-photon emission computed tomography (SPECT)/CT can assess the primary osseointegration of a stemless shoulder prosthesis in the recent postoperative state [12]. Bone Scan Shoulder There is no relevant literature to support the use of a bone scan of the shoulder in the follow-up of the asymptomatic patient with a primary shoulder arthroplasty. CT Shoulder CT examinations are not typically ordered for evaluation of the asymptomatic patient.

Imaging After Shoulder Arthroplasty PCAs. The standard single-phase bone scan involves imaging 2 to 3 hours after MDP administration. The 3-phase bone scan consists of a 1-minute radionuclide angiogram followed by immediate blood pool images and 2- to 3-hour delayed views. The 3-phase scan can be helpful in the assessment of acute fracture and differentiating acute osteomyelitis from cellulitis. A positive 3-phase bone scan is often seen in neuropathic arthropathy. The use of radiolabeled white blood cells (WBC) with In-111 in conjunction with bone marrow imaging, utilizing Tc-99m sulfur colloid, can help to differentiate neuropathic reactive bone marrow from acute osteomyelitis. Serial bone scans can also assist in assessing postoperative bone remodeling and periprosthetic fracture from aseptic periprosthetic loosening. The value of WBC and marrow imaging is not only to differentiate neuropathic arthropathy from acute osteomyelitis but also to differentiate aseptic loosening from acute osteomyelitis. Like neuropathic arthropathy, aseptic loosening will demonstrate spatially congruent WBC and marrow activity, consistent with reactive or hematopoietically active marrow. Imaging After Shoulder Arthroplasty Discussion of Procedures by Variant Variant 1: Routine follow-up of the asymptomatic patient with a primary shoulder arthroplasty. 3-Phase Bone Scan with SPECT or SPECT/CT Shoulder A 3-phase bone scan is not typically ordered for evaluation of the asymptomatic patient. Although, single-photon emission computed tomography (SPECT)/CT can assess the primary osseointegration of a stemless shoulder prosthesis in the recent postoperative state [12]. Bone Scan Shoulder There is no relevant literature to support the use of a bone scan of the shoulder in the follow-up of the asymptomatic patient with a primary shoulder arthroplasty. CT Shoulder CT examinations are not typically ordered for evaluation of the asymptomatic patient.

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acrac_3097049_4

Imaging After Shoulder Arthroplasty PCAs

Fluoride PET/CT Skull Base to Mid-Thigh There is no relevant literature to support the use of fluoride PET/CT skull base to mid-thigh in the follow-up of the asymptomatic patient with a primary shoulder arthroplasty. MRI Shoulder MRI examinations are not typically ordered for evaluation of the asymptomatic patient. Radiographs are also typically ordered for yearly follow-up examinations to assess interval changes in the bone surrounding the prosthesis [16]. The presence of scapular notching on postoperative radiographs of reverse total shoulder prostheses has been associated with poor clinical outcomes [17]. The risk for loosening increases over time, with notable radiographic changes associated with loosening found at least 5 years after surgery, most commonly involving the glenoid component [18]. Late complications requiring revision surgery, such as loosening, infection, and fracture, occurring up to 15 years postoperatively, suggests the need for long-term radiographic follow-up when these complications are asymptomatic or their outcome can be affected by early detection on radiographs [10]. US Shoulder US examinations are not typically ordered for evaluation of the asymptomatic patient. 3-Phase Bone Scan with SPECT or SPECT/CT Shoulder There is no relevant literature to support the use of a 3-phase bone scan with SPECT or SPECT/CT as a first-line imaging modality in the acutely symptomatic patient with a primary shoulder arthroplasty. Similar to bone scans, a 3-phase bone scan is highly sensitive for the detection of periprosthetic fractures but suffers from low specificity. Imaging After Shoulder Arthroplasty Acute periprosthetic fractures are often 3-phase bone scan positive and demonstrate focal increased activity at the fracture site, which decreases over time, corresponding to fracture healing. Fracture hyperemia also typically resolves with the acute/subacute phases.

Imaging After Shoulder Arthroplasty PCAs. Fluoride PET/CT Skull Base to Mid-Thigh There is no relevant literature to support the use of fluoride PET/CT skull base to mid-thigh in the follow-up of the asymptomatic patient with a primary shoulder arthroplasty. MRI Shoulder MRI examinations are not typically ordered for evaluation of the asymptomatic patient. Radiographs are also typically ordered for yearly follow-up examinations to assess interval changes in the bone surrounding the prosthesis [16]. The presence of scapular notching on postoperative radiographs of reverse total shoulder prostheses has been associated with poor clinical outcomes [17]. The risk for loosening increases over time, with notable radiographic changes associated with loosening found at least 5 years after surgery, most commonly involving the glenoid component [18]. Late complications requiring revision surgery, such as loosening, infection, and fracture, occurring up to 15 years postoperatively, suggests the need for long-term radiographic follow-up when these complications are asymptomatic or their outcome can be affected by early detection on radiographs [10]. US Shoulder US examinations are not typically ordered for evaluation of the asymptomatic patient. 3-Phase Bone Scan with SPECT or SPECT/CT Shoulder There is no relevant literature to support the use of a 3-phase bone scan with SPECT or SPECT/CT as a first-line imaging modality in the acutely symptomatic patient with a primary shoulder arthroplasty. Similar to bone scans, a 3-phase bone scan is highly sensitive for the detection of periprosthetic fractures but suffers from low specificity. Imaging After Shoulder Arthroplasty Acute periprosthetic fractures are often 3-phase bone scan positive and demonstrate focal increased activity at the fracture site, which decreases over time, corresponding to fracture healing. Fracture hyperemia also typically resolves with the acute/subacute phases.

3097049

acrac_3097049_5

Imaging After Shoulder Arthroplasty PCAs

The addition of SPECT or SPECT/CT improves diagnosis by allowing more accurate anatomical localization of new bone formation [20]. The specificity of Tc-99m bone scans for periprosthetic fractures increases in older prostheses once postoperative remodeling has decreased. Bone Scan Shoulder There is no relevant literature to support the use of a bone scan as a first-line imaging modality in the acutely symptomatic patient with a primary shoulder arthroplasty. Tc-99m single- and 3-phase bone scans are very sensitive but with low specificity in the diagnosis of post arthroplasty fractures, and imaging findings can overlap with other abnormalities such as loosening and infection [21]. Without a radionuclide angiogram and blood pool phase, the single-phase bone scan will not depict the acute peri fracture hyperemia. Acute periprosthetic fractures are often 3- phase bone scan positive and demonstrate focal increased activity at the fracture site, which decreases over time, corresponding to fracture healing. Fracture hyperemia also typically resolves with the acute/subacute phases. Uncomplicated fracture healing may take up to 2 years before a bone scan normalizes [21,22]. In addition, increased bone uptake can be seen at the site of arthroplasty, related to postoperative bone remodeling for up to 1 year following surgery, which can further complicate matters [21]. The specificity of Tc-99m bone scan imaging for periprosthetic fracture increases in older prostheses once the postoperative remodeling has decreased and stabilized. CT Shoulder CT is not typically ordered for the initial evaluation of a symptomatic shoulder arthroplasty. CT with metal reduction protocol can be subsequently used to detect loosening and to further delineate a periprosthetic fracture seen on radiographs in terms of degree of displacement, extent, and comminution.

Imaging After Shoulder Arthroplasty PCAs. The addition of SPECT or SPECT/CT improves diagnosis by allowing more accurate anatomical localization of new bone formation [20]. The specificity of Tc-99m bone scans for periprosthetic fractures increases in older prostheses once postoperative remodeling has decreased. Bone Scan Shoulder There is no relevant literature to support the use of a bone scan as a first-line imaging modality in the acutely symptomatic patient with a primary shoulder arthroplasty. Tc-99m single- and 3-phase bone scans are very sensitive but with low specificity in the diagnosis of post arthroplasty fractures, and imaging findings can overlap with other abnormalities such as loosening and infection [21]. Without a radionuclide angiogram and blood pool phase, the single-phase bone scan will not depict the acute peri fracture hyperemia. Acute periprosthetic fractures are often 3- phase bone scan positive and demonstrate focal increased activity at the fracture site, which decreases over time, corresponding to fracture healing. Fracture hyperemia also typically resolves with the acute/subacute phases. Uncomplicated fracture healing may take up to 2 years before a bone scan normalizes [21,22]. In addition, increased bone uptake can be seen at the site of arthroplasty, related to postoperative bone remodeling for up to 1 year following surgery, which can further complicate matters [21]. The specificity of Tc-99m bone scan imaging for periprosthetic fracture increases in older prostheses once the postoperative remodeling has decreased and stabilized. CT Shoulder CT is not typically ordered for the initial evaluation of a symptomatic shoulder arthroplasty. CT with metal reduction protocol can be subsequently used to detect loosening and to further delineate a periprosthetic fracture seen on radiographs in terms of degree of displacement, extent, and comminution.

3097049

acrac_3097049_6

Imaging After Shoulder Arthroplasty PCAs

CT can also be used when a fracture is suspected clinically but the radiographs are negative such as in the setting of a suspected acromial stress fracture in the patient with a reverse total shoulder arthroplasty [23]. Fluoride PET/CT Skull Base to Mid-Thigh There is no relevant literature to support the use of fluoride PET/CT as a first-line imaging modality in the acutely symptomatic patient with a primary shoulder arthroplasty. MRI Shoulder MRI is not typically ordered for the initial evaluation of a symptomatic shoulder arthroplasty but, in the opinion of the committee, can play a contributory role when fractures are occult on radiographs and/or CT examinations. MRI can identify the location of the fracture by detecting associated marrow edema and, not infrequently, an associated fracture line. MRI also well delineates soft-tissue abnormalities in the setting of infection and rotator cuff injury. Radiography Shoulder Radiography is the first and main imaging modality utilized in the evaluation of both the symptomatic and asymptomatic shoulder arthroplasty [10,13]. Findings on radiographs can be used to diagnose and guide further assessment of both osseous and high-grade rotator cuff abnormalities. Radiographs are particularly helpful for the detection of scapular fractures that can occur with relatively minor trauma in patients with reverse shoulder prostheses [24]. US Shoulder US examinations are not typically ordered as a first-line study for evaluation of pain in the setting of shoulder arthroplasty. Nevertheless, US provides assessment of the rotator cuff integrity and is capable of detecting cortical discontinuity and step-off in the setting of a fracture after shoulder arthroplasty [25]. Variant 3: Symptomatic patient with a primary shoulder arthroplasty, infection not excluded. Additional imaging following radiographs.

Imaging After Shoulder Arthroplasty PCAs. CT can also be used when a fracture is suspected clinically but the radiographs are negative such as in the setting of a suspected acromial stress fracture in the patient with a reverse total shoulder arthroplasty [23]. Fluoride PET/CT Skull Base to Mid-Thigh There is no relevant literature to support the use of fluoride PET/CT as a first-line imaging modality in the acutely symptomatic patient with a primary shoulder arthroplasty. MRI Shoulder MRI is not typically ordered for the initial evaluation of a symptomatic shoulder arthroplasty but, in the opinion of the committee, can play a contributory role when fractures are occult on radiographs and/or CT examinations. MRI can identify the location of the fracture by detecting associated marrow edema and, not infrequently, an associated fracture line. MRI also well delineates soft-tissue abnormalities in the setting of infection and rotator cuff injury. Radiography Shoulder Radiography is the first and main imaging modality utilized in the evaluation of both the symptomatic and asymptomatic shoulder arthroplasty [10,13]. Findings on radiographs can be used to diagnose and guide further assessment of both osseous and high-grade rotator cuff abnormalities. Radiographs are particularly helpful for the detection of scapular fractures that can occur with relatively minor trauma in patients with reverse shoulder prostheses [24]. US Shoulder US examinations are not typically ordered as a first-line study for evaluation of pain in the setting of shoulder arthroplasty. Nevertheless, US provides assessment of the rotator cuff integrity and is capable of detecting cortical discontinuity and step-off in the setting of a fracture after shoulder arthroplasty [25]. Variant 3: Symptomatic patient with a primary shoulder arthroplasty, infection not excluded. Additional imaging following radiographs.

3097049

acrac_3097049_7

Imaging After Shoulder Arthroplasty PCAs

Infection, including osteomyelitis and septic arthritis, after total shoulder arthroplasty is an uncommon albeit potentially devastating complication, with a prevalence of 0.7% to 2.9%. Infection is more common in males and a younger age group [3,26,27]. A 97% infection-free rate at 20 years has been reported [28]. Predisposing underlying conditions may include rheumatoid arthritis, corticosteroid use, diabetes, repeated intra-articular steroid injections, and prior shoulder surgery [26]. Infection rates are higher in the setting of reverse total shoulder arthroplasties, with a range of 0.8% to 10% [29]. Proposed causes for this higher prevalence include longer procedural time and steeper learning curve to perform the surgery, large dead space, multiple previous operations, and advanced patient age [29]. Imaging After Shoulder Arthroplasty 3-Phase Bone Scan and WBC Scan and Sulfur Colloid Scan Shoulder For infection imaging, In-111-labeled WBC with a Tc-99m sulfur colloid bone marrow study is a sensitive and specific test for acute osteomyelitis. An isolated In-111 WBC study is a sensitive but nonspecific technique for the evaluation of acute neutrophilic dominant periprosthetic infection [11]. Its specificity can be increased when interpreted in conjunction with a Tc-99m sulfur colloid study or, less optimally, a bone scan, which may not be indicated if both In-111 WBC and sulfur colloid studies have been performed [11,30]. Tc-99m 3-phase bone scan is a highly sensitive modality for identifying osteolysis and increased osteoblastic activity from postoperative bony remodeling, aseptic loosening, acute osteomyelitis, and periprosthetic fractures. The specificity of bone scans increases in older prostheses once postoperative remodeling has stabilized. Concordant increased labeled WBC and marrow activity is consistent with reactive marrow seen in postoperative change, aseptic loosening, and fractures. Postoperative change and fracture healing tend to decrease over time.

Imaging After Shoulder Arthroplasty PCAs. Infection, including osteomyelitis and septic arthritis, after total shoulder arthroplasty is an uncommon albeit potentially devastating complication, with a prevalence of 0.7% to 2.9%. Infection is more common in males and a younger age group [3,26,27]. A 97% infection-free rate at 20 years has been reported [28]. Predisposing underlying conditions may include rheumatoid arthritis, corticosteroid use, diabetes, repeated intra-articular steroid injections, and prior shoulder surgery [26]. Infection rates are higher in the setting of reverse total shoulder arthroplasties, with a range of 0.8% to 10% [29]. Proposed causes for this higher prevalence include longer procedural time and steeper learning curve to perform the surgery, large dead space, multiple previous operations, and advanced patient age [29]. Imaging After Shoulder Arthroplasty 3-Phase Bone Scan and WBC Scan and Sulfur Colloid Scan Shoulder For infection imaging, In-111-labeled WBC with a Tc-99m sulfur colloid bone marrow study is a sensitive and specific test for acute osteomyelitis. An isolated In-111 WBC study is a sensitive but nonspecific technique for the evaluation of acute neutrophilic dominant periprosthetic infection [11]. Its specificity can be increased when interpreted in conjunction with a Tc-99m sulfur colloid study or, less optimally, a bone scan, which may not be indicated if both In-111 WBC and sulfur colloid studies have been performed [11,30]. Tc-99m 3-phase bone scan is a highly sensitive modality for identifying osteolysis and increased osteoblastic activity from postoperative bony remodeling, aseptic loosening, acute osteomyelitis, and periprosthetic fractures. The specificity of bone scans increases in older prostheses once postoperative remodeling has stabilized. Concordant increased labeled WBC and marrow activity is consistent with reactive marrow seen in postoperative change, aseptic loosening, and fractures. Postoperative change and fracture healing tend to decrease over time.

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acrac_3097049_8

Imaging After Shoulder Arthroplasty PCAs

Fracture confirmation can also be identified with anatomic imaging (eg, radiographs, CT with metal artifact reduction techniques). Normal uncomplicated postoperative change tends to decrease over time and up to 2 years or longer after surgery [21,22], whereas aseptic loosening generally tends to progress. Discordant activity of increased labeled WBC and a photopenic bone marrow is consistent with acute osteomyelitis. 3-Phase Bone Scan and WBC Scan and Sulfur Colloid Scan with SPECT or SPECT/CT Shoulder The use of nuclear imaging for the evaluation of periprosthetic infection has been limited to the evaluation of hip and knee arthroplasties, but various clinical studies anecdotally suggest utilizing this modality in shoulder arthroplasties [30]. Tc-99m 3-phase bone scan is a highly sensitive modality for the detection of acute osteomyelitis in the setting of normal radiographs but remains low in specificity because the imaging findings can overlap with other abnormalities such as mechanical loosening and osteolysis [30]. In addition, increased bone uptake can be seen at the site of arthroplasty, related to postoperative bone remodeling, for up to 1 year following surgery [30]. A bone scan is also limited in its ability to assess the periprosthetic soft tissues for the presence of an abscess. The addition of a bone scan SPECT/CT improves contrast resolution and anatomic localization of radiopharmaceutical uptake and provides a limited CT in the area of concern. A blood pool SPECT/CT over the targeted clinical area can be obtained immediately after the static blood pool images and further localizes foci of hyperemia [31-33]. At 2 to 3 hours after radiopharmaceutical administration and the standard bone scan images, a second SPECT/CT over the area(s) of interest can localize new bone formation [30] but remains nonspecific. A positive 3-phase bone scan can be seen in periprosthetic infection, periprosthetic fracture, and in the early postoperative state.

Imaging After Shoulder Arthroplasty PCAs. Fracture confirmation can also be identified with anatomic imaging (eg, radiographs, CT with metal artifact reduction techniques). Normal uncomplicated postoperative change tends to decrease over time and up to 2 years or longer after surgery [21,22], whereas aseptic loosening generally tends to progress. Discordant activity of increased labeled WBC and a photopenic bone marrow is consistent with acute osteomyelitis. 3-Phase Bone Scan and WBC Scan and Sulfur Colloid Scan with SPECT or SPECT/CT Shoulder The use of nuclear imaging for the evaluation of periprosthetic infection has been limited to the evaluation of hip and knee arthroplasties, but various clinical studies anecdotally suggest utilizing this modality in shoulder arthroplasties [30]. Tc-99m 3-phase bone scan is a highly sensitive modality for the detection of acute osteomyelitis in the setting of normal radiographs but remains low in specificity because the imaging findings can overlap with other abnormalities such as mechanical loosening and osteolysis [30]. In addition, increased bone uptake can be seen at the site of arthroplasty, related to postoperative bone remodeling, for up to 1 year following surgery [30]. A bone scan is also limited in its ability to assess the periprosthetic soft tissues for the presence of an abscess. The addition of a bone scan SPECT/CT improves contrast resolution and anatomic localization of radiopharmaceutical uptake and provides a limited CT in the area of concern. A blood pool SPECT/CT over the targeted clinical area can be obtained immediately after the static blood pool images and further localizes foci of hyperemia [31-33]. At 2 to 3 hours after radiopharmaceutical administration and the standard bone scan images, a second SPECT/CT over the area(s) of interest can localize new bone formation [30] but remains nonspecific. A positive 3-phase bone scan can be seen in periprosthetic infection, periprosthetic fracture, and in the early postoperative state.

3097049

acrac_3097049_9

Imaging After Shoulder Arthroplasty PCAs

Postoperative change and fracture healing tend to decrease over time. Fracture confirmation can also be identified with anatomic imaging (eg, radiographs, CT with metal artifact reduction techniques). Normal uncomplicated postoperative change tends to decrease over time and up to 2 years or longer after surgery [21,22], whereas aseptic loosening generally tends to progress. The specificity of bone scans increases in older prostheses once the postoperative remodeling has stabilized. The addition of SPECT/CT with the In-111 WBC and sulfur colloid scans increases contrast resolution and anatomic localization of radiopharmaceutical activity. Utilizing subtraction imaging on the SPECT/CT studies (subtracting the sulfur colloid from WBC images) can identify whether an area of concern on the bone scan is concordant with similar increased WBC and marrow activity (reactive marrow) or discordant (WBC activity with absent sulfur colloid activity), the latter consistent with an acute pyogenic process/osteomyelitis. 3-Phase Bone Scan with SPECT or SPECT/CT Shoulder The use of nuclear imaging for the evaluation of periprosthetic infection has been limited to the evaluation of hip and knee arthroplasties, but various clinical studies anecdotally suggest utilizing this modality in shoulder arthroplasties [30]. Imaging After Shoulder Arthroplasty Tc-99m 3-phase bone scan is a highly sensitive modality for the detection of acute osteomyelitis in the setting of normal radiographs but remains low in specificity as the imaging findings can overlap with other abnormalities such as mechanical loosening and osteolysis [30]. In addition, increased bone uptake can be seen at the site of arthroplasty, related to postoperative bone remodeling, for up to 1 year following surgery [30]. A bone scan is also limited in its ability to assess the periprosthetic soft tissues for the presence of an abscess.

Imaging After Shoulder Arthroplasty PCAs. Postoperative change and fracture healing tend to decrease over time. Fracture confirmation can also be identified with anatomic imaging (eg, radiographs, CT with metal artifact reduction techniques). Normal uncomplicated postoperative change tends to decrease over time and up to 2 years or longer after surgery [21,22], whereas aseptic loosening generally tends to progress. The specificity of bone scans increases in older prostheses once the postoperative remodeling has stabilized. The addition of SPECT/CT with the In-111 WBC and sulfur colloid scans increases contrast resolution and anatomic localization of radiopharmaceutical activity. Utilizing subtraction imaging on the SPECT/CT studies (subtracting the sulfur colloid from WBC images) can identify whether an area of concern on the bone scan is concordant with similar increased WBC and marrow activity (reactive marrow) or discordant (WBC activity with absent sulfur colloid activity), the latter consistent with an acute pyogenic process/osteomyelitis. 3-Phase Bone Scan with SPECT or SPECT/CT Shoulder The use of nuclear imaging for the evaluation of periprosthetic infection has been limited to the evaluation of hip and knee arthroplasties, but various clinical studies anecdotally suggest utilizing this modality in shoulder arthroplasties [30]. Imaging After Shoulder Arthroplasty Tc-99m 3-phase bone scan is a highly sensitive modality for the detection of acute osteomyelitis in the setting of normal radiographs but remains low in specificity as the imaging findings can overlap with other abnormalities such as mechanical loosening and osteolysis [30]. In addition, increased bone uptake can be seen at the site of arthroplasty, related to postoperative bone remodeling, for up to 1 year following surgery [30]. A bone scan is also limited in its ability to assess the periprosthetic soft tissues for the presence of an abscess.

3097049

acrac_3097049_10

Imaging After Shoulder Arthroplasty PCAs

The addition of SPECT or SPECT/CT improves anatomic localization of new bone formation [20] but remains nonspecific. A positive 3-phase bone scan can be seen in periprosthetic infection, periprosthetic fracture, and in the early postoperative state. Postoperative change and fracture healing tend to decrease over time. Fracture confirmation can also be identified with anatomic imaging (eg, radiographs, CT with metal artifact reduction techniques). Normal uncomplicated postoperative change tends to decrease over time and up to 2 years or longer after surgery [21,22], whereas aseptic loosening generally tends to progress. The specificity of bone scans increases in older prostheses once the postoperative remodeling has stabilized. Image-Guided Aspiration Shoulder Aspiration of the shoulder should be performed when there is suspicion for an infected shoulder arthroplasty clinically, with or without radiographic evidence of infection, to avoid the destructive soft-tissue and bone changes that can result from an untreated infection. Imaging-guided aspiration procedures provide a minimally invasive means to sample fluid from the joint suspected of infection [34,35]. Shoulder joint aspiration has been shown to have a sensitivity of 33% and specificity of 98% [36]. Shoulder aspiration can be completed with the use of fluoroscopy, US, and CT guidance. MR guidance is possible but rarely utilized. Arthrography can be performed along with aspiration, when done under fluoroscopy and CT, to confirm the intra-articular origin of any aspirated fluid as well as to assess for any extension of the infectious process into adjacent bursae, sinus tracts, and abscesses [34]. Bone Scan Shoulder The use of nuclear imaging for the evaluation of periprosthetic infection has been limited to the evaluation of hip and knee arthroplasties, but various clinical studies anecdotally suggest utilizing this modality in shoulder arthroplasties [30].

Imaging After Shoulder Arthroplasty PCAs. The addition of SPECT or SPECT/CT improves anatomic localization of new bone formation [20] but remains nonspecific. A positive 3-phase bone scan can be seen in periprosthetic infection, periprosthetic fracture, and in the early postoperative state. Postoperative change and fracture healing tend to decrease over time. Fracture confirmation can also be identified with anatomic imaging (eg, radiographs, CT with metal artifact reduction techniques). Normal uncomplicated postoperative change tends to decrease over time and up to 2 years or longer after surgery [21,22], whereas aseptic loosening generally tends to progress. The specificity of bone scans increases in older prostheses once the postoperative remodeling has stabilized. Image-Guided Aspiration Shoulder Aspiration of the shoulder should be performed when there is suspicion for an infected shoulder arthroplasty clinically, with or without radiographic evidence of infection, to avoid the destructive soft-tissue and bone changes that can result from an untreated infection. Imaging-guided aspiration procedures provide a minimally invasive means to sample fluid from the joint suspected of infection [34,35]. Shoulder joint aspiration has been shown to have a sensitivity of 33% and specificity of 98% [36]. Shoulder aspiration can be completed with the use of fluoroscopy, US, and CT guidance. MR guidance is possible but rarely utilized. Arthrography can be performed along with aspiration, when done under fluoroscopy and CT, to confirm the intra-articular origin of any aspirated fluid as well as to assess for any extension of the infectious process into adjacent bursae, sinus tracts, and abscesses [34]. Bone Scan Shoulder The use of nuclear imaging for the evaluation of periprosthetic infection has been limited to the evaluation of hip and knee arthroplasties, but various clinical studies anecdotally suggest utilizing this modality in shoulder arthroplasties [30].

3097049

acrac_3097049_11

Imaging After Shoulder Arthroplasty PCAs

The standard Tc-99m bone scan is a sensitive modality for the identification of abnormal bone in acute osteomyelitis, particularly in the setting of normal radiographs. However, the 3-phase bone scan is often preferred to assess for associated hyperemia in acute fracture and acute osteomyelitis. Bone scans remain low in specificity as the imaging findings can overlap with other abnormalities, such as mechanical loosening with osteolysis [30], periprosthetic fracture, and postarthroplasty bone remodeling, which can be seen up to 1 year following surgery [30]. Postoperative change and fracture healing tend to decrease over time. Fracture confirmation can also be identified with anatomic imaging (eg, radiographs, CT with metal artifact reduction techniques). Normal uncomplicated postoperative change tends to decrease over time and up to 2 years or longer after surgery [21,22], whereas aseptic loosening generally tends to progress. The specificity of bone scans for periprosthetic fracture or infection increases in older prostheses once the postoperative remodeling has stabilized. CT Shoulder CT with metal reduction protocols can elucidate the findings seen on radiographs and can further narrow the differential diagnosis in a patient suspected of periprosthetic infection as well as assist in preoperative planning [3]. CT may play a more important role after removal of the hardware and debridement in a patient with infection because it can help quantify the amount of remaining bone that can be used for revision arthroplasty [3]. CT can also be used to evaluate the surrounding soft tissues for infection and to aid in planning before image-guided joint aspiration. Administration of intravenous (IV) contrast improves the evaluation of adjacent soft-tissue fluid collections/abscesses and sinus tracts.

Imaging After Shoulder Arthroplasty PCAs. The standard Tc-99m bone scan is a sensitive modality for the identification of abnormal bone in acute osteomyelitis, particularly in the setting of normal radiographs. However, the 3-phase bone scan is often preferred to assess for associated hyperemia in acute fracture and acute osteomyelitis. Bone scans remain low in specificity as the imaging findings can overlap with other abnormalities, such as mechanical loosening with osteolysis [30], periprosthetic fracture, and postarthroplasty bone remodeling, which can be seen up to 1 year following surgery [30]. Postoperative change and fracture healing tend to decrease over time. Fracture confirmation can also be identified with anatomic imaging (eg, radiographs, CT with metal artifact reduction techniques). Normal uncomplicated postoperative change tends to decrease over time and up to 2 years or longer after surgery [21,22], whereas aseptic loosening generally tends to progress. The specificity of bone scans for periprosthetic fracture or infection increases in older prostheses once the postoperative remodeling has stabilized. CT Shoulder CT with metal reduction protocols can elucidate the findings seen on radiographs and can further narrow the differential diagnosis in a patient suspected of periprosthetic infection as well as assist in preoperative planning [3]. CT may play a more important role after removal of the hardware and debridement in a patient with infection because it can help quantify the amount of remaining bone that can be used for revision arthroplasty [3]. CT can also be used to evaluate the surrounding soft tissues for infection and to aid in planning before image-guided joint aspiration. Administration of intravenous (IV) contrast improves the evaluation of adjacent soft-tissue fluid collections/abscesses and sinus tracts.

3097049

acrac_3097049_12

Imaging After Shoulder Arthroplasty PCAs

Fluoride PET/CT Skull Base to Mid-Thigh There is no relevant literature to support the use of fluoride PET/CT for the next imaging study of a symptomatic patient with a primary shoulder arthroplasty when infection has been not excluded. MRI Shoulder MRI with metal reduction protocols can play a useful role in the diagnosis [37,38] and assessment of periprosthetic infection, particularly when other modalities fail to confirm the clinical suspicion of infection. MRI can demonstrate osseous and soft-tissue abnormalities associated with periprosthetic infection [28,39]. MRI can depict marrow edema suggestive of osteomyelitis. It can depict bony destruction, which can be difficult to note on radiographs, Imaging After Shoulder Arthroplasty related to osteomyelitis. MRI can also demonstrate joint effusions, adjacent soft-tissue edema, and fluid loculations suggestive of abscesses. Administration of IV contrast improves the evaluation of adjacent soft-tissue fluid collections/abscesses and sinus tracts. US Shoulder US examinations are increasingly being ordered for evaluation of periprosthetic infection in the setting of shoulder arthroplasty to evaluate for joint effusion and surrounding soft-tissue infection. US may be of use for the evaluation of a joint effusion, bursal distention, and the surrounding soft-tissues for signs of infection including abscesses [40- 42], which need aspiration and testing to determine the presence of infection and identification of the underlying microorganism. US is useful to evaluate the surrounding soft tissues for infection and to aid in planning before image-guided joint aspiration in order to avoid seeding of a sterile joint effusion from overlying soft-tissue infection. WBC Scan and Sulfur Colloid Scan Shoulder For infection imaging, In-111 WBC imaging in conjunction with Tc-99m sulfur colloid marrow imaging is a sensitive and specific test.

Imaging After Shoulder Arthroplasty PCAs. Fluoride PET/CT Skull Base to Mid-Thigh There is no relevant literature to support the use of fluoride PET/CT for the next imaging study of a symptomatic patient with a primary shoulder arthroplasty when infection has been not excluded. MRI Shoulder MRI with metal reduction protocols can play a useful role in the diagnosis [37,38] and assessment of periprosthetic infection, particularly when other modalities fail to confirm the clinical suspicion of infection. MRI can demonstrate osseous and soft-tissue abnormalities associated with periprosthetic infection [28,39]. MRI can depict marrow edema suggestive of osteomyelitis. It can depict bony destruction, which can be difficult to note on radiographs, Imaging After Shoulder Arthroplasty related to osteomyelitis. MRI can also demonstrate joint effusions, adjacent soft-tissue edema, and fluid loculations suggestive of abscesses. Administration of IV contrast improves the evaluation of adjacent soft-tissue fluid collections/abscesses and sinus tracts. US Shoulder US examinations are increasingly being ordered for evaluation of periprosthetic infection in the setting of shoulder arthroplasty to evaluate for joint effusion and surrounding soft-tissue infection. US may be of use for the evaluation of a joint effusion, bursal distention, and the surrounding soft-tissues for signs of infection including abscesses [40- 42], which need aspiration and testing to determine the presence of infection and identification of the underlying microorganism. US is useful to evaluate the surrounding soft tissues for infection and to aid in planning before image-guided joint aspiration in order to avoid seeding of a sterile joint effusion from overlying soft-tissue infection. WBC Scan and Sulfur Colloid Scan Shoulder For infection imaging, In-111 WBC imaging in conjunction with Tc-99m sulfur colloid marrow imaging is a sensitive and specific test.

3097049

acrac_3097049_13

Imaging After Shoulder Arthroplasty PCAs

An isolated In-111-labeled WBC study is a sensitive but nonspecific technique for the evaluation of acute neutrophilic dominant periprosthetic infection [11]. Its specificity can be increased when interpreted alongside Tc-99m sulfur colloid imaging or, less optimally, bone scan imaging; the latter may not be indicated if both In-111 WBC and sulfur colloid imaging have been performed [11,21,30]. Variant 4: Symptomatic patient with a primary shoulder arthroplasty, infection excluded. Suspected loosening. Additional imaging following radiographs. Aseptic loosening, also referred to as mechanical loosening, is used to describe a hardware abnormality that results from a noninfectious etiology. One of the most common causes of aseptic loosening is osteolysis, a foreign-body response to debris that results from wear and breakdown of the hardware components, such as the acetabular polyethylene liner, cement, and/or metallic elements. Osteolysis can cause extensive, often asymptomatic, bone loss [43-45]. Although this process has been described extensively in the literature for hip arthroplasty, the literature on the topic is sparse in patients with shoulder arthroplasties [23,46]. 3-Phase Bone Scan with SPECT or SPECT/CT Shoulder Tc-99m 3-phase bone scan is a highly sensitive modality for the detection of acute osteomyelitis in the setting of normal radiographs but remains low in specificity because the imaging findings can overlap with other abnormalities, such as mechanical loosening with osteolysis and periprosthestic fracture [30]. In addition, increased bone uptake can be identified at the site of arthroplasty, related to postoperative bone remodeling, and seen for up to 1 year following surgery [30]. The addition of SPECT or SPECT/CT improves anatomic localization of active bone remodeling [20], however, remains nonspecific.

Imaging After Shoulder Arthroplasty PCAs. An isolated In-111-labeled WBC study is a sensitive but nonspecific technique for the evaluation of acute neutrophilic dominant periprosthetic infection [11]. Its specificity can be increased when interpreted alongside Tc-99m sulfur colloid imaging or, less optimally, bone scan imaging; the latter may not be indicated if both In-111 WBC and sulfur colloid imaging have been performed [11,21,30]. Variant 4: Symptomatic patient with a primary shoulder arthroplasty, infection excluded. Suspected loosening. Additional imaging following radiographs. Aseptic loosening, also referred to as mechanical loosening, is used to describe a hardware abnormality that results from a noninfectious etiology. One of the most common causes of aseptic loosening is osteolysis, a foreign-body response to debris that results from wear and breakdown of the hardware components, such as the acetabular polyethylene liner, cement, and/or metallic elements. Osteolysis can cause extensive, often asymptomatic, bone loss [43-45]. Although this process has been described extensively in the literature for hip arthroplasty, the literature on the topic is sparse in patients with shoulder arthroplasties [23,46]. 3-Phase Bone Scan with SPECT or SPECT/CT Shoulder Tc-99m 3-phase bone scan is a highly sensitive modality for the detection of acute osteomyelitis in the setting of normal radiographs but remains low in specificity because the imaging findings can overlap with other abnormalities, such as mechanical loosening with osteolysis and periprosthestic fracture [30]. In addition, increased bone uptake can be identified at the site of arthroplasty, related to postoperative bone remodeling, and seen for up to 1 year following surgery [30]. The addition of SPECT or SPECT/CT improves anatomic localization of active bone remodeling [20], however, remains nonspecific.

3097049

acrac_3097049_14

Imaging After Shoulder Arthroplasty PCAs

A positive 3-phase bone scan can be seen in the early postoperative state, periprosthetic fracture, aseptic prosthetic loosening, and periprosthetic infection. Postoperative change and fracture healing tend to decrease over time. Fracture confirmation can also be identified with anatomic imaging (eg, radiographs, CT with metal artifact reduction techniques). SPECT/CT also has the potential to differentiate symptomatic from asymptomatic scapular notching associated with reverse shoulder prostheses [30]. Normal uncomplicated postoperative change tends to decrease over time and up to 2 years or longer after surgery [21,22], whereas aseptic loosening generally tends to progress. The specificity of bone scans for periprosthetic complications increases in older prostheses once the postoperative remodeling has stabilized. Bone Scan Shoulder Tc-99m single-phase bone scan imaging is a sensitive modality for the diagnosis of loosening in the setting of normal radiographs but remains low in specificity because the imaging findings can overlap with other abnormalities such as postoperative bone remodeling, periprosthetic fracture, and infection [30]. Normal uncomplicated increased periprosthetic uptake related to postoperative bone remodeling tends to decrease over time and up 2 years or longer after surgery [21,30], whereas aseptic loosening generally tends to progress. The specificity of bone scans for periprosthetic fracture, loosening, or infection increases in older prostheses once the postoperative remodeling has stabilized. CT Shoulder CT plays an important role in the imaging evaluation of a patient with potential loosening that may be missed or incompletely evaluated with radiographs [10,47]. CT provides a better means of evaluating the hardware components and surrounding bone stock [48]. CT can also assess changes in component alignment over time [49].

Imaging After Shoulder Arthroplasty PCAs. A positive 3-phase bone scan can be seen in the early postoperative state, periprosthetic fracture, aseptic prosthetic loosening, and periprosthetic infection. Postoperative change and fracture healing tend to decrease over time. Fracture confirmation can also be identified with anatomic imaging (eg, radiographs, CT with metal artifact reduction techniques). SPECT/CT also has the potential to differentiate symptomatic from asymptomatic scapular notching associated with reverse shoulder prostheses [30]. Normal uncomplicated postoperative change tends to decrease over time and up to 2 years or longer after surgery [21,22], whereas aseptic loosening generally tends to progress. The specificity of bone scans for periprosthetic complications increases in older prostheses once the postoperative remodeling has stabilized. Bone Scan Shoulder Tc-99m single-phase bone scan imaging is a sensitive modality for the diagnosis of loosening in the setting of normal radiographs but remains low in specificity because the imaging findings can overlap with other abnormalities such as postoperative bone remodeling, periprosthetic fracture, and infection [30]. Normal uncomplicated increased periprosthetic uptake related to postoperative bone remodeling tends to decrease over time and up 2 years or longer after surgery [21,30], whereas aseptic loosening generally tends to progress. The specificity of bone scans for periprosthetic fracture, loosening, or infection increases in older prostheses once the postoperative remodeling has stabilized. CT Shoulder CT plays an important role in the imaging evaluation of a patient with potential loosening that may be missed or incompletely evaluated with radiographs [10,47]. CT provides a better means of evaluating the hardware components and surrounding bone stock [48]. CT can also assess changes in component alignment over time [49].

3097049

acrac_3097049_15

Imaging After Shoulder Arthroplasty PCAs

Imaging After Shoulder Arthroplasty Image degradation can occur because of beam hardening artifact and other hardware-related artifacts, especially with older CT scanners. The use of newer metal reduction CT software has decreased the artifact-related limitations, improving evaluation [50-52]. Furthermore, dual-energy CT, employing virtual noncalcium software, may provide useful information regarding the presence of marrow edema [53]. CT can also be used to evaluate the bone density around prostheses, which may be predictive of loosening [54]. Metal reduction protocols and modifications in patient positioning have greatly enhanced the ability of CT to evaluate for complications associated with shoulder arthroplasties. Nevertheless, there are scant studies assessing the benefit of CT in patients with postoperative complications. In a few reports, each including a small group of patients, CT compared with radiographs, has been found to better demonstrate imaging findings such as periprosthetic lucency, osteolysis, hardware malposition, and component migration, as well as the degree of osseous incorporation along the glenoid, deficiency of which has been associated with the risk of failure [10,47,55]. Evaluation of bone graft resorption remains limited on CT because of metal artifact [56]. Dual-energy CT virtual noncalcium techniques, although not yet specifically studied in the postoperative shoulder, may potentially provide useful information about marrow edema associated with the above abnormalities [53]. The addition of intra-articular or IV contrast does not typically improve evaluation [57]. Fluoride PET/CT Skull Base to Mid-Thigh There is no relevant literature to support the use of fluoride PET/CT after radiographs in a symptomatic patient with a primary shoulder arthroplasty and infection was excluded.

Imaging After Shoulder Arthroplasty PCAs. Imaging After Shoulder Arthroplasty Image degradation can occur because of beam hardening artifact and other hardware-related artifacts, especially with older CT scanners. The use of newer metal reduction CT software has decreased the artifact-related limitations, improving evaluation [50-52]. Furthermore, dual-energy CT, employing virtual noncalcium software, may provide useful information regarding the presence of marrow edema [53]. CT can also be used to evaluate the bone density around prostheses, which may be predictive of loosening [54]. Metal reduction protocols and modifications in patient positioning have greatly enhanced the ability of CT to evaluate for complications associated with shoulder arthroplasties. Nevertheless, there are scant studies assessing the benefit of CT in patients with postoperative complications. In a few reports, each including a small group of patients, CT compared with radiographs, has been found to better demonstrate imaging findings such as periprosthetic lucency, osteolysis, hardware malposition, and component migration, as well as the degree of osseous incorporation along the glenoid, deficiency of which has been associated with the risk of failure [10,47,55]. Evaluation of bone graft resorption remains limited on CT because of metal artifact [56]. Dual-energy CT virtual noncalcium techniques, although not yet specifically studied in the postoperative shoulder, may potentially provide useful information about marrow edema associated with the above abnormalities [53]. The addition of intra-articular or IV contrast does not typically improve evaluation [57]. Fluoride PET/CT Skull Base to Mid-Thigh There is no relevant literature to support the use of fluoride PET/CT after radiographs in a symptomatic patient with a primary shoulder arthroplasty and infection was excluded.

3097049

acrac_3097049_16

Imaging After Shoulder Arthroplasty PCAs

MRI Shoulder Evolving MRI methods with improved image quality and metal artifact reduction have rendered the modality a more feasible technique for the diagnosis of component loosening, rotator cuff tearing, and, in the presence of hemiarthroplasty, glenoid cartilage wear [37-39,58]. Because of developments in metal reduction protocols for MRI and research studies showing the benefit of MRI, it can be effective in the evaluation of aseptic loosening [37-39]. US Shoulder US is limited in the ability to evaluate bone-related complications such as loosening [10]. Variant 5: Symptomatic patient with a primary shoulder arthroplasty, infection excluded. Suspected rotator cuff tear or other soft-tissue abnormality. Additional imaging following radiographs. The prevalence of rotator cuff tears after arthroplasty placement has been reported to be up to 1.3% [3]. Tears of the subscapularis tendon can present with clinical and radiographic signs of anterior shoulder instability, including varying degrees of anterior subluxation as well as frank dislocation of the humeral head component relative to the glenoid [6,10]. 3-Phase Bone Scan with SPECT or SPECT/CT Shoulder Nuclear medicine examinations are not typically ordered for the evaluation of rotator cuff tendon abnormalities. Bone Scan Shoulder Nuclear medicine examinations are not typically ordered for the evaluation of rotator cuff tendon abnormalities. CT Arthrography Shoulder The inherent limited tissue-contrast resolution of CT detracts from its ability to detect rotator cuff tears. A CT arthrogram can be performed when there is suspicion of a rotator cuff tear [10]. CT arthrography can be an effective modality to evaluate the rotator cuff and detect any associated pathology [10,59]. The technique, however, is relatively weak in its ability to assess the extent of partial rotator cuff tears as well in identifying the exact location of the tear when compared with MRI.

Imaging After Shoulder Arthroplasty PCAs. MRI Shoulder Evolving MRI methods with improved image quality and metal artifact reduction have rendered the modality a more feasible technique for the diagnosis of component loosening, rotator cuff tearing, and, in the presence of hemiarthroplasty, glenoid cartilage wear [37-39,58]. Because of developments in metal reduction protocols for MRI and research studies showing the benefit of MRI, it can be effective in the evaluation of aseptic loosening [37-39]. US Shoulder US is limited in the ability to evaluate bone-related complications such as loosening [10]. Variant 5: Symptomatic patient with a primary shoulder arthroplasty, infection excluded. Suspected rotator cuff tear or other soft-tissue abnormality. Additional imaging following radiographs. The prevalence of rotator cuff tears after arthroplasty placement has been reported to be up to 1.3% [3]. Tears of the subscapularis tendon can present with clinical and radiographic signs of anterior shoulder instability, including varying degrees of anterior subluxation as well as frank dislocation of the humeral head component relative to the glenoid [6,10]. 3-Phase Bone Scan with SPECT or SPECT/CT Shoulder Nuclear medicine examinations are not typically ordered for the evaluation of rotator cuff tendon abnormalities. Bone Scan Shoulder Nuclear medicine examinations are not typically ordered for the evaluation of rotator cuff tendon abnormalities. CT Arthrography Shoulder The inherent limited tissue-contrast resolution of CT detracts from its ability to detect rotator cuff tears. A CT arthrogram can be performed when there is suspicion of a rotator cuff tear [10]. CT arthrography can be an effective modality to evaluate the rotator cuff and detect any associated pathology [10,59]. The technique, however, is relatively weak in its ability to assess the extent of partial rotator cuff tears as well in identifying the exact location of the tear when compared with MRI.

3097049

acrac_3097049_17

Imaging After Shoulder Arthroplasty PCAs

The presence and degree of fatty muscle replacement can also be used as an indirect sign of a rotator cuff tear [60,61]. Administration of IV contrast does not improve evaluation. CT Shoulder The inherent limited tissue-contrast resolution of CT detracts from its ability to detect rotator cuff tears. CT shows promise in assessing the location of the glenoid and humeral components of reverse shoulder prostheses in the setting of soft-tissue impingement [62]. Administration of IV contrast does not improve evaluation. Fluoride PET/CT Skull Base to Mid-Thigh Nuclear medicine examinations are not typically ordered for the evaluation of rotator cuff tendon abnormalities. Imaging After Shoulder Arthroplasty MRI Shoulder Evolving MRI methods with improved image quality and metal artifact reduction have rendered the modality a more feasible technique for the diagnosis of component loosening, rotator cuff tearing, and, in the presence of hemiarthroplasty, glenoid cartilage wear [37-39,58]. MRI can be used to evaluate for rotator cuff tendon tearing in the setting of shoulder arthroplasty [38,39]. Advanced metal reduction techniques can reduce the prosthesis-related artifact and thus improve visualization of the rotator cuff tendons and any associated pathology [37,38]. Compared with the other imaging techniques, MRI can also provide a more global evaluation of the arthroplasty components as well as the surrounding soft tissues [37,38]. MRI with metal reduction techniques can also demonstrate failure of subscapularis tendon repair in the setting of arthroplasty, the most common location for rotator cuff pathology in this setting [38]. There are multiple techniques used to release the subscapularis tendon during arthroplasty placement, including tenotomy, osteotomy, and peel [10].

Imaging After Shoulder Arthroplasty PCAs. The presence and degree of fatty muscle replacement can also be used as an indirect sign of a rotator cuff tear [60,61]. Administration of IV contrast does not improve evaluation. CT Shoulder The inherent limited tissue-contrast resolution of CT detracts from its ability to detect rotator cuff tears. CT shows promise in assessing the location of the glenoid and humeral components of reverse shoulder prostheses in the setting of soft-tissue impingement [62]. Administration of IV contrast does not improve evaluation. Fluoride PET/CT Skull Base to Mid-Thigh Nuclear medicine examinations are not typically ordered for the evaluation of rotator cuff tendon abnormalities. Imaging After Shoulder Arthroplasty MRI Shoulder Evolving MRI methods with improved image quality and metal artifact reduction have rendered the modality a more feasible technique for the diagnosis of component loosening, rotator cuff tearing, and, in the presence of hemiarthroplasty, glenoid cartilage wear [37-39,58]. MRI can be used to evaluate for rotator cuff tendon tearing in the setting of shoulder arthroplasty [38,39]. Advanced metal reduction techniques can reduce the prosthesis-related artifact and thus improve visualization of the rotator cuff tendons and any associated pathology [37,38]. Compared with the other imaging techniques, MRI can also provide a more global evaluation of the arthroplasty components as well as the surrounding soft tissues [37,38]. MRI with metal reduction techniques can also demonstrate failure of subscapularis tendon repair in the setting of arthroplasty, the most common location for rotator cuff pathology in this setting [38]. There are multiple techniques used to release the subscapularis tendon during arthroplasty placement, including tenotomy, osteotomy, and peel [10].

3097049

acrac_69502_0

Sinonasal Disease

Introduction/Background According to the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS), the term rhinosinusitis refers to symptomatic inflammation of the nasal cavity and paranasal sinuses and is preferred over the term sinusitis, because inflammation of the nasal cavity nearly always accompanies inflammation of the contiguous paranasal sinuses. Rhinosinusitis may be classified as acute rhinosinusitis (ARS) if symptoms last <4 weeks or as chronic rhinosinusitis (CRS) if symptoms last >12 weeks [1]. Patients with acute bacterial rhinosinusitis (ABRS) may develop orbital, intracranial, and vascular complications, including orbital cellulitis, subperiosteal abscess, intracranial abscess, cerebritis, cavernous sinus thrombosis, and aneurysm. Acute recurrent rhinosinusitis refers to when patients have 4 or more episodes of rhinosinusitis per year without persistent symptoms between episodes. CRS is one of the most common chronic illnesses in the United States, affecting approximately 12% to 16% of the population [2], with an overall annual economic burden estimated at $22 billion [3]. Acute invasive fungal sinusitis is a fungal infection of the paranasal sinuses with a rapid time course of <4 weeks [4] and a high mortality rate of 50% to 80% [5,6]. Affected patients are typically immunocompromised and include patients with neutropenia, hematologic malignancies, poorly controlled diabetes, acquired immunodeficiency syndrome, organ transplantation, and patients on immunosuppressive therapy including systemic steroids and chemotherapy [4]. Presenting symptoms are nonspecific and include fever, rhinorrhea, and diplopia, similar to those seen with ABRS. Clinicians should maintain a high index of suspicion for this diagnosis in immunocompromised patients with symptoms of ARS, orbital symptoms, and/or headache. [4]. Sinonasal neoplasms account for 3% of head and neck neoplasms [7].

Sinonasal Disease. Introduction/Background According to the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS), the term rhinosinusitis refers to symptomatic inflammation of the nasal cavity and paranasal sinuses and is preferred over the term sinusitis, because inflammation of the nasal cavity nearly always accompanies inflammation of the contiguous paranasal sinuses. Rhinosinusitis may be classified as acute rhinosinusitis (ARS) if symptoms last <4 weeks or as chronic rhinosinusitis (CRS) if symptoms last >12 weeks [1]. Patients with acute bacterial rhinosinusitis (ABRS) may develop orbital, intracranial, and vascular complications, including orbital cellulitis, subperiosteal abscess, intracranial abscess, cerebritis, cavernous sinus thrombosis, and aneurysm. Acute recurrent rhinosinusitis refers to when patients have 4 or more episodes of rhinosinusitis per year without persistent symptoms between episodes. CRS is one of the most common chronic illnesses in the United States, affecting approximately 12% to 16% of the population [2], with an overall annual economic burden estimated at $22 billion [3]. Acute invasive fungal sinusitis is a fungal infection of the paranasal sinuses with a rapid time course of <4 weeks [4] and a high mortality rate of 50% to 80% [5,6]. Affected patients are typically immunocompromised and include patients with neutropenia, hematologic malignancies, poorly controlled diabetes, acquired immunodeficiency syndrome, organ transplantation, and patients on immunosuppressive therapy including systemic steroids and chemotherapy [4]. Presenting symptoms are nonspecific and include fever, rhinorrhea, and diplopia, similar to those seen with ABRS. Clinicians should maintain a high index of suspicion for this diagnosis in immunocompromised patients with symptoms of ARS, orbital symptoms, and/or headache. [4]. Sinonasal neoplasms account for 3% of head and neck neoplasms [7].

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acrac_69502_1

Sinonasal Disease

Patients with a sinonasal mass may present with nasal congestion, nasal fullness, anosmia, rhinorrhea, and epistaxis [8,9]. Benign lesions include papilloma, respiratory epithelial adenomatoid hamartoma, pleomorphic adenoma, juvenile nasopharyngeal angiofibroma, nerve sheath tumor, and meningioma [7,8]. The most common sinonasal malignancy is squamous cell carcinoma, with other malignancies lymphoma, neuroendocrine tumors, salivary gland tumors, and melanoma [7,10]. aNew York University Langone Health, New York, New York. bPanel Chair, University of Iowa Hospitals and Clinics, Iowa City, Iowa. cPanel Vice-Chair, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts. dFroedtert Memorial Lutheran Hospital Medical College of Wisconsin, Milwaukee, Wisconsin. eMontefiore Medical Center, Bronx, New York. fHouston Methodist Hospital, Houston, Texas. gUniversity of Texas Health Science Center, Houston, Texas. hThe University of Texas MD Anderson Cancer Center, Houston, Texas. iMetroHealth Medical Center, Cleveland, Ohio. jEastern Virginia Medical School, Norfolk, Virginia; American Academy of Otolaryngology-Head and Neck Surgery. kUniversity of Texas Health Science Center, Houston, Texas. lMayo Clinic Arizona, Phoenix, Arizona. mUniversity of Iowa Carver College of Medicine, Iowa City, Iowa, Primary care physician. nUniversity of Otago, Dunedin, Otepoti, New Zealand. oGeorge Washington University Hospital, Washington, District of Columbia. pUniversity of Colorado Denver, Denver, Colorado. qSpecialty Chair, Atlanta VA Health Care System and Emory University, Atlanta, Georgia. The American College of Radiology seeks and encourages collaboration with other organizations on the development of the ACR Appropriateness Criteria through representation of such organizations on expert panels. Participation on the expert panel does not necessarily imply endorsement of the final document by individual contributors or their respective organization.

Sinonasal Disease. Patients with a sinonasal mass may present with nasal congestion, nasal fullness, anosmia, rhinorrhea, and epistaxis [8,9]. Benign lesions include papilloma, respiratory epithelial adenomatoid hamartoma, pleomorphic adenoma, juvenile nasopharyngeal angiofibroma, nerve sheath tumor, and meningioma [7,8]. The most common sinonasal malignancy is squamous cell carcinoma, with other malignancies lymphoma, neuroendocrine tumors, salivary gland tumors, and melanoma [7,10]. aNew York University Langone Health, New York, New York. bPanel Chair, University of Iowa Hospitals and Clinics, Iowa City, Iowa. cPanel Vice-Chair, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts. dFroedtert Memorial Lutheran Hospital Medical College of Wisconsin, Milwaukee, Wisconsin. eMontefiore Medical Center, Bronx, New York. fHouston Methodist Hospital, Houston, Texas. gUniversity of Texas Health Science Center, Houston, Texas. hThe University of Texas MD Anderson Cancer Center, Houston, Texas. iMetroHealth Medical Center, Cleveland, Ohio. jEastern Virginia Medical School, Norfolk, Virginia; American Academy of Otolaryngology-Head and Neck Surgery. kUniversity of Texas Health Science Center, Houston, Texas. lMayo Clinic Arizona, Phoenix, Arizona. mUniversity of Iowa Carver College of Medicine, Iowa City, Iowa, Primary care physician. nUniversity of Otago, Dunedin, Otepoti, New Zealand. oGeorge Washington University Hospital, Washington, District of Columbia. pUniversity of Colorado Denver, Denver, Colorado. qSpecialty Chair, Atlanta VA Health Care System and Emory University, Atlanta, Georgia. The American College of Radiology seeks and encourages collaboration with other organizations on the development of the ACR Appropriateness Criteria through representation of such organizations on expert panels. Participation on the expert panel does not necessarily imply endorsement of the final document by individual contributors or their respective organization.

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acrac_69502_2

Sinonasal Disease

Reprint requests to: publications@acr.org Arteriography Craniofacial There is no relevant literature to support the use of arteriography in the evaluation of acute uncomplicated rhinosinusitis. CT Cone Beam Paranasal Sinuses As per clinical practice guidelines from the AAO-HNS, CT imaging of the sinuses is unnecessary for patients with a clinical diagnosis of ARS [1]. CT has not been shown to accurately distinguish ABRS from ARS of viral etiology [1,17,18]. Moreover, cone beam CT (CBCT) is limited in the evaluation of the soft tissues and is therefore not helpful in the imaging assessment of complications of sinus disease [19]. CT Head As per clinical practice guidelines from the AAO-HNS, imaging is unnecessary for patients with a clinical diagnosis of ARS [1]. There is no relevant literature to support the use of CT head in the evaluation of acute uncomplicated rhinosinusitis. CT Maxillofacial As per clinical practice guidelines from the AAO-HNS, CT imaging of the sinuses is unnecessary for patients with a clinical diagnosis of ARS [1]. CT has not been shown to accurately distinguish ABRS from ARS of viral etiology [1,17,18]. CTA Head There is no relevant literature to support the use of CT angiography (CTA) head in the evaluation of acute uncomplicated rhinosinusitis. FDG-PET/CT Skull Base to Mid-Thigh There is no relevant literature to support the use of fluorine-18-2-fluoro-2-deoxy-D-glucose (FDG)-PET/CT in the evaluation of acute uncomplicated rhinosinusitis. MRA Head There is no relevant literature to support the use of MR angiography (MRA) head in the evaluation of acute uncomplicated rhinosinusitis. Sinonasal Disease MRI Head As per clinical practice guidelines from the AAO-HNS, imaging is unnecessary for patients with a clinical diagnosis of ARS [1]. There is no relevant literature to support the use of MRI head in the evaluation of acute uncomplicated rhinosinusitis.

Sinonasal Disease. Reprint requests to: publications@acr.org Arteriography Craniofacial There is no relevant literature to support the use of arteriography in the evaluation of acute uncomplicated rhinosinusitis. CT Cone Beam Paranasal Sinuses As per clinical practice guidelines from the AAO-HNS, CT imaging of the sinuses is unnecessary for patients with a clinical diagnosis of ARS [1]. CT has not been shown to accurately distinguish ABRS from ARS of viral etiology [1,17,18]. Moreover, cone beam CT (CBCT) is limited in the evaluation of the soft tissues and is therefore not helpful in the imaging assessment of complications of sinus disease [19]. CT Head As per clinical practice guidelines from the AAO-HNS, imaging is unnecessary for patients with a clinical diagnosis of ARS [1]. There is no relevant literature to support the use of CT head in the evaluation of acute uncomplicated rhinosinusitis. CT Maxillofacial As per clinical practice guidelines from the AAO-HNS, CT imaging of the sinuses is unnecessary for patients with a clinical diagnosis of ARS [1]. CT has not been shown to accurately distinguish ABRS from ARS of viral etiology [1,17,18]. CTA Head There is no relevant literature to support the use of CT angiography (CTA) head in the evaluation of acute uncomplicated rhinosinusitis. FDG-PET/CT Skull Base to Mid-Thigh There is no relevant literature to support the use of fluorine-18-2-fluoro-2-deoxy-D-glucose (FDG)-PET/CT in the evaluation of acute uncomplicated rhinosinusitis. MRA Head There is no relevant literature to support the use of MR angiography (MRA) head in the evaluation of acute uncomplicated rhinosinusitis. Sinonasal Disease MRI Head As per clinical practice guidelines from the AAO-HNS, imaging is unnecessary for patients with a clinical diagnosis of ARS [1]. There is no relevant literature to support the use of MRI head in the evaluation of acute uncomplicated rhinosinusitis.

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acrac_69502_3

Sinonasal Disease

MRI Orbits, Face, and Neck As per clinical practice guidelines from the AAO-HNS, imaging is unnecessary for patients with a clinical diagnosis of ARS [1]. There is no relevant literature to support the use of MRI of the orbits, face, and neck in the evaluation of acute uncomplicated rhinosinusitis. Radiography Paranasal Sinuses As per clinical practice guidelines from the AAO-HNS, imaging of the sinuses is unnecessary for patients with a clinical diagnosis of ARS [1]. Radiography lacks specificity for the identification of ABRS, because sinus fluid can also be seen with viral upper respiratory tract infections [20]. Compared with CT, radiography has been shown to have a low sensitivity of 25% to 41% for all sinus groups except the maxillary sinuses with 80% sensitivity [21]. In a meta-analysis of 6 studies, radiographs of the paranasal sinuses demonstrated a sensitivity of 76% and specificity of 79% for the diagnosis of ABRS compared with sinus puncture [22]. SPECT or SPECT/CT Paranasal Sinuses There is no relevant literature to support the use of single-photon emission CT (SPECT) or SPECT/CT in the evaluation of acute uncomplicated rhinosinusitis. Variant 2: Acute rhinosinusitis with suspected orbital or intracranial complication. Initial imaging. ABRS may spread to the orbital and intracranial compartments through neurovascular foramina, areas of osseous erosion, or hematogenous spread along valveless veins [6]. Orbital complications are more common and include orbital cellulitis, subperiosteal abscess, and orbital abscess. Symptoms suggesting orbital involvement include eye swelling with or without proptosis, impaired eye movement, and decreased visual acuity [17,23]. Intracranial complications most commonly occur with frontal sinusitis and include epidural abscess, subdural empyema, cerebritis, brain abscess, and meningitis. Symptoms suggesting intracranial involvement include severe headache, photophobia, seizures, or other focal neurologic findings [6,17].

Sinonasal Disease. MRI Orbits, Face, and Neck As per clinical practice guidelines from the AAO-HNS, imaging is unnecessary for patients with a clinical diagnosis of ARS [1]. There is no relevant literature to support the use of MRI of the orbits, face, and neck in the evaluation of acute uncomplicated rhinosinusitis. Radiography Paranasal Sinuses As per clinical practice guidelines from the AAO-HNS, imaging of the sinuses is unnecessary for patients with a clinical diagnosis of ARS [1]. Radiography lacks specificity for the identification of ABRS, because sinus fluid can also be seen with viral upper respiratory tract infections [20]. Compared with CT, radiography has been shown to have a low sensitivity of 25% to 41% for all sinus groups except the maxillary sinuses with 80% sensitivity [21]. In a meta-analysis of 6 studies, radiographs of the paranasal sinuses demonstrated a sensitivity of 76% and specificity of 79% for the diagnosis of ABRS compared with sinus puncture [22]. SPECT or SPECT/CT Paranasal Sinuses There is no relevant literature to support the use of single-photon emission CT (SPECT) or SPECT/CT in the evaluation of acute uncomplicated rhinosinusitis. Variant 2: Acute rhinosinusitis with suspected orbital or intracranial complication. Initial imaging. ABRS may spread to the orbital and intracranial compartments through neurovascular foramina, areas of osseous erosion, or hematogenous spread along valveless veins [6]. Orbital complications are more common and include orbital cellulitis, subperiosteal abscess, and orbital abscess. Symptoms suggesting orbital involvement include eye swelling with or without proptosis, impaired eye movement, and decreased visual acuity [17,23]. Intracranial complications most commonly occur with frontal sinusitis and include epidural abscess, subdural empyema, cerebritis, brain abscess, and meningitis. Symptoms suggesting intracranial involvement include severe headache, photophobia, seizures, or other focal neurologic findings [6,17].

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acrac_69502_4

Sinonasal Disease

Vascular complications include cavernous sinus thrombosis and rarely pseudoaneurysm formation [2,24]. Arteriography Craniofacial Arteriography may be performed for the evaluation of a pseudoaneurysm, although this would not be performed in the initial imaging evaluation. There is no relevant literature to support the use of arteriography in the evaluation of ARS with suspected orbital or intracranial complication. CT Cone Beam Paranasal Sinuses CBCT is not helpful in the imaging assessment of patients with ARS with suspected orbital or intracranial complications because of a limited evaluation of the soft-tissue structures [19,25]. CT Head CT maxillofacial is useful as the first-line CT examination for patients with ARS with suspected intraorbital and intracranial complications, because complications adjacent to the paranasal sinuses are typically included in the field of view. MRI is overall more useful than CT for the evaluation of intracranial complications, but because CT may be the first imaging study ordered, contrast-enhanced CT head may be added to the CT maxillofacial examination for increased coverage of a suspected intracranial complication. CT head with intravenous (IV) contrast can accurately identify clinically suspected intracranial complications including epidural abscess, subdural empyema, cerebritis, and brain abscess. The accuracy for the detection of intracranial complications has been reported to be 87% for CT, compared with 97% for MRI [23], although the detection of cavernous sinus thrombosis, meningitis, and early cerebritis is more difficult on CT compared with MRI [6,17,23]. There is no relevant literature to support the use of noncontrast CT head or combined pre- and postcontrast CT imaging. CT Maxillofacial CT of the paranasal sinuses with IV contrast can accurately confirm paranasal sinus inflammation and identify orbital complications and adjacent intracranial complications included in the field of view [17].

Sinonasal Disease. Vascular complications include cavernous sinus thrombosis and rarely pseudoaneurysm formation [2,24]. Arteriography Craniofacial Arteriography may be performed for the evaluation of a pseudoaneurysm, although this would not be performed in the initial imaging evaluation. There is no relevant literature to support the use of arteriography in the evaluation of ARS with suspected orbital or intracranial complication. CT Cone Beam Paranasal Sinuses CBCT is not helpful in the imaging assessment of patients with ARS with suspected orbital or intracranial complications because of a limited evaluation of the soft-tissue structures [19,25]. CT Head CT maxillofacial is useful as the first-line CT examination for patients with ARS with suspected intraorbital and intracranial complications, because complications adjacent to the paranasal sinuses are typically included in the field of view. MRI is overall more useful than CT for the evaluation of intracranial complications, but because CT may be the first imaging study ordered, contrast-enhanced CT head may be added to the CT maxillofacial examination for increased coverage of a suspected intracranial complication. CT head with intravenous (IV) contrast can accurately identify clinically suspected intracranial complications including epidural abscess, subdural empyema, cerebritis, and brain abscess. The accuracy for the detection of intracranial complications has been reported to be 87% for CT, compared with 97% for MRI [23], although the detection of cavernous sinus thrombosis, meningitis, and early cerebritis is more difficult on CT compared with MRI [6,17,23]. There is no relevant literature to support the use of noncontrast CT head or combined pre- and postcontrast CT imaging. CT Maxillofacial CT of the paranasal sinuses with IV contrast can accurately confirm paranasal sinus inflammation and identify orbital complications and adjacent intracranial complications included in the field of view [17].

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acrac_69502_5

Sinonasal Disease

Given its detailed depiction of bony anatomy, CT can also accurately demonstrate the presence of erosions of the sinus and orbital walls. Studies have demonstrated a higher accuracy of CT compared with clinical examination for detecting orbital complications, with an accuracy of 87% to 91% [23]. CT also enables surgical planning given its detailed depiction Sinonasal Disease of sinonasal anatomy and can be used for surgical image-guidance systems. Although MRI is overall more useful than CT for the evaluation of intracranial and intraorbital complications, CT is often the first imaging study ordered. A noncontrast CT may be performed for bony evaluation and surgical planning but is limited in the detection of orbital and intracranial complications. There is no relevant literature to support the use of combined pre- and postcontrast CT imaging. CTA Head CTA head may be performed for the evaluation of a pseudoaneurysm, but this is typically not performed in the initial imaging evaluation. There is no relevant literature to support the use of CTA head in the evaluation of ARS with suspected orbital or intracranial complication. FDG-PET/CT Skull Base to Mid-Thigh There is no relevant literature to support the use of FDG-PET/CT in the evaluation of ARS with suspected orbital or intracranial complication. MRA Head MRA head may be performed for the evaluation of a pseudoaneurysm, but this is typically not performed in the initial imaging evaluation. There is no relevant literature to support the use of MRA head in the evaluation of ARS with suspected orbital or intracranial complication. MRI Head MRI head without and with IV contrast can accurately identify clinically suspected intracranial complications including cavernous sinus thrombosis, epidural abscess, subdural empyema, cerebritis, brain abscess, and meningitis, with a reported 97% diagnostic accuracy compared with 87% for CT and a superior accuracy in particular for the diagnosis of meningitis [17,23].

Sinonasal Disease. Given its detailed depiction of bony anatomy, CT can also accurately demonstrate the presence of erosions of the sinus and orbital walls. Studies have demonstrated a higher accuracy of CT compared with clinical examination for detecting orbital complications, with an accuracy of 87% to 91% [23]. CT also enables surgical planning given its detailed depiction Sinonasal Disease of sinonasal anatomy and can be used for surgical image-guidance systems. Although MRI is overall more useful than CT for the evaluation of intracranial and intraorbital complications, CT is often the first imaging study ordered. A noncontrast CT may be performed for bony evaluation and surgical planning but is limited in the detection of orbital and intracranial complications. There is no relevant literature to support the use of combined pre- and postcontrast CT imaging. CTA Head CTA head may be performed for the evaluation of a pseudoaneurysm, but this is typically not performed in the initial imaging evaluation. There is no relevant literature to support the use of CTA head in the evaluation of ARS with suspected orbital or intracranial complication. FDG-PET/CT Skull Base to Mid-Thigh There is no relevant literature to support the use of FDG-PET/CT in the evaluation of ARS with suspected orbital or intracranial complication. MRA Head MRA head may be performed for the evaluation of a pseudoaneurysm, but this is typically not performed in the initial imaging evaluation. There is no relevant literature to support the use of MRA head in the evaluation of ARS with suspected orbital or intracranial complication. MRI Head MRI head without and with IV contrast can accurately identify clinically suspected intracranial complications including cavernous sinus thrombosis, epidural abscess, subdural empyema, cerebritis, brain abscess, and meningitis, with a reported 97% diagnostic accuracy compared with 87% for CT and a superior accuracy in particular for the diagnosis of meningitis [17,23].

69502

acrac_69502_6

Sinonasal Disease

Combined pre- and postcontrast imaging provides the best opportunity to identify and characterize potential intracranial complications. Restricted diffusion on diffusion- weighted sequences can accurately identify the presence of purulent material within extra-axial collections and brain abscesses. MRI Orbits, Face, and Neck MRI orbits, face, and neck without and with IV contrast can confirm paranasal sinus inflammation and identify orbital complications and adjacent intracranial complications included in the field of view [17]. This study may be done in conjunction with MRI head for suspected orbital and intracranial complications. Although noncontrast imaging can demonstrate fluid collections and edema, combined pre- and postcontrast imaging provides the best opportunity to identify and characterize potential orbital and intracranial complications. Radiography Paranasal Sinuses There is no relevant literature to support the use of radiography in the evaluation of ARS with suspected orbital or intracranial complication. Radiography is limited in the evaluation of soft-tissue structures. SPECT or SPECT/CT Paranasal Sinuses There is no relevant literature to support the use of SPECT or SPECT/CT in the evaluation of ARS with suspected orbital or intracranial complication. Variant 3: Acute recurrent sinusitis or chronic rhinosinusitis or noninvasive fungal sinusitis or sinonasal polyposis. Possible surgical candidate for these indications or other non-neoplastic indications, including suspected silent sinus syndrome or suspected mucocele, or deviated nasal septum. Initial imaging. CRS refers to rhinosinusitis lasting >12 weeks, and the most common symptoms of CRS include nasal obstruction, facial congestion and pressure, discolored nasal discharge, and hyposmia [26].

Sinonasal Disease. Combined pre- and postcontrast imaging provides the best opportunity to identify and characterize potential intracranial complications. Restricted diffusion on diffusion- weighted sequences can accurately identify the presence of purulent material within extra-axial collections and brain abscesses. MRI Orbits, Face, and Neck MRI orbits, face, and neck without and with IV contrast can confirm paranasal sinus inflammation and identify orbital complications and adjacent intracranial complications included in the field of view [17]. This study may be done in conjunction with MRI head for suspected orbital and intracranial complications. Although noncontrast imaging can demonstrate fluid collections and edema, combined pre- and postcontrast imaging provides the best opportunity to identify and characterize potential orbital and intracranial complications. Radiography Paranasal Sinuses There is no relevant literature to support the use of radiography in the evaluation of ARS with suspected orbital or intracranial complication. Radiography is limited in the evaluation of soft-tissue structures. SPECT or SPECT/CT Paranasal Sinuses There is no relevant literature to support the use of SPECT or SPECT/CT in the evaluation of ARS with suspected orbital or intracranial complication. Variant 3: Acute recurrent sinusitis or chronic rhinosinusitis or noninvasive fungal sinusitis or sinonasal polyposis. Possible surgical candidate for these indications or other non-neoplastic indications, including suspected silent sinus syndrome or suspected mucocele, or deviated nasal septum. Initial imaging. CRS refers to rhinosinusitis lasting >12 weeks, and the most common symptoms of CRS include nasal obstruction, facial congestion and pressure, discolored nasal discharge, and hyposmia [26].

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acrac_69502_7

Sinonasal Disease

The presence of 2 or more of these symptoms for >12 weeks is highly sensitive for the diagnosis of CRS, but because these symptoms are nonspecific, documentation of inflammation on endoscopy or imaging is required to confirm the diagnosis [26]. Imaging findings that confirm CRS include mucosal thickening, sinus opacification, polyps or retention cysts, and sclerosis and thickening of the sinus walls [2,26]. Studies have shown variable correlation between the imaging findings and clinical symptoms of CRS. The Lund- Mackay and modified Lund-Mackay system are the most commonly used imaging staging systems, with some studies showing good correlation with disease severity and surgical outcomes [2,27,28]. Some studies have not demonstrated a correlation between symptom severity and CT findings [29-31], although correlation may be higher in patients with associated nasal polyps [29]. Sinonasal Disease Functional endoscopic sinus surgery is now the standard of care for restoring patency of paranasal sinus outflow tracts, with postoperative improvement in symptoms and quality of life reported in over 75% of patients [32]. Functional endoscopic sinus surgery may be performed for CRS and other nonneoplastic indications including acute recurrent rhinosinusitis, noninvasive fungal sinusitis and fungus ball, sinonasal polyposis, silent sinus syndrome, mucocele, and deviated nasal septum. Imaging that provides anatomical detail is needed for surgical planning, in particular for the identification of anatomic variants and abnormalities that can increase the risk for intracranial, intraorbital, and vascular injury. Arteriography Craniofacial There is no relevant literature to support the use of arteriography in the evaluation of CRS or for presurgical planning of paranasal sinus inflammatory disease. CT Cone Beam Paranasal Sinuses CBCT has been shown to have high accuracy for evaluating odontogenic and nonodontogenic sinusitis, with strong agreement between CBCT and sinus endoscopy [33].

Sinonasal Disease. The presence of 2 or more of these symptoms for >12 weeks is highly sensitive for the diagnosis of CRS, but because these symptoms are nonspecific, documentation of inflammation on endoscopy or imaging is required to confirm the diagnosis [26]. Imaging findings that confirm CRS include mucosal thickening, sinus opacification, polyps or retention cysts, and sclerosis and thickening of the sinus walls [2,26]. Studies have shown variable correlation between the imaging findings and clinical symptoms of CRS. The Lund- Mackay and modified Lund-Mackay system are the most commonly used imaging staging systems, with some studies showing good correlation with disease severity and surgical outcomes [2,27,28]. Some studies have not demonstrated a correlation between symptom severity and CT findings [29-31], although correlation may be higher in patients with associated nasal polyps [29]. Sinonasal Disease Functional endoscopic sinus surgery is now the standard of care for restoring patency of paranasal sinus outflow tracts, with postoperative improvement in symptoms and quality of life reported in over 75% of patients [32]. Functional endoscopic sinus surgery may be performed for CRS and other nonneoplastic indications including acute recurrent rhinosinusitis, noninvasive fungal sinusitis and fungus ball, sinonasal polyposis, silent sinus syndrome, mucocele, and deviated nasal septum. Imaging that provides anatomical detail is needed for surgical planning, in particular for the identification of anatomic variants and abnormalities that can increase the risk for intracranial, intraorbital, and vascular injury. Arteriography Craniofacial There is no relevant literature to support the use of arteriography in the evaluation of CRS or for presurgical planning of paranasal sinus inflammatory disease. CT Cone Beam Paranasal Sinuses CBCT has been shown to have high accuracy for evaluating odontogenic and nonodontogenic sinusitis, with strong agreement between CBCT and sinus endoscopy [33].

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Sinonasal Disease

Similar to standard multidetector CT, CBCT can confirm the diagnosis of CRS and identify anatomic variants for presurgical planning. One study showed decreased detection of intrasinus calcifications in patients with noninvasive fungal sinusitis compared with multidetector CT, although comparison between the 2 modalities was done in separate patient cohorts [34]. CBCT is limited in the evaluation of soft-tissue structures and therefore is not the imaging modality of choice if extrasinus disease is suspected [19,25]. CT Head Given its typical incomplete coverage of the paranasal sinuses, CT head is not typically performed for the evaluation of CRS or for presurgical planning of paranasal sinus inflammatory disease. CT Maxillofacial Given its excellent bony detail, multidetector CT without IV contrast is useful for confirming and evaluating CRS and for presurgical planning. Imaging findings that confirm CRS include mucosal thickening, sinus opacification, polyps or retention cysts, and sclerosis and thickening of the sinus walls [2,26]. CT has been shown to accurately identify these findings of CRS, although the findings have been shown to not necessarily correlate with the severity of symptoms [26]. CT can also evaluate the extent of disease and identify anatomic variants that narrow sinus drainage pathways [32]. CT is critical for surgical planning, in particular for the identification of anatomic variants and abnormalities that can increase the risk for intracranial, intraorbital, and vascular injury as well as for CSF leak [31,32]. Low-dose techniques have been shown to be limited in the visualization of surgically relevant anatomical structures including the cribriform plates, lamina papyracea, and anterior ethmoidal artery canal in the setting of CRS with nasal polyps and a history of sinus surgery [35]. A sinus CT protocol that can be utilized by image guidance systems is recommended [36].

Sinonasal Disease. Similar to standard multidetector CT, CBCT can confirm the diagnosis of CRS and identify anatomic variants for presurgical planning. One study showed decreased detection of intrasinus calcifications in patients with noninvasive fungal sinusitis compared with multidetector CT, although comparison between the 2 modalities was done in separate patient cohorts [34]. CBCT is limited in the evaluation of soft-tissue structures and therefore is not the imaging modality of choice if extrasinus disease is suspected [19,25]. CT Head Given its typical incomplete coverage of the paranasal sinuses, CT head is not typically performed for the evaluation of CRS or for presurgical planning of paranasal sinus inflammatory disease. CT Maxillofacial Given its excellent bony detail, multidetector CT without IV contrast is useful for confirming and evaluating CRS and for presurgical planning. Imaging findings that confirm CRS include mucosal thickening, sinus opacification, polyps or retention cysts, and sclerosis and thickening of the sinus walls [2,26]. CT has been shown to accurately identify these findings of CRS, although the findings have been shown to not necessarily correlate with the severity of symptoms [26]. CT can also evaluate the extent of disease and identify anatomic variants that narrow sinus drainage pathways [32]. CT is critical for surgical planning, in particular for the identification of anatomic variants and abnormalities that can increase the risk for intracranial, intraorbital, and vascular injury as well as for CSF leak [31,32]. Low-dose techniques have been shown to be limited in the visualization of surgically relevant anatomical structures including the cribriform plates, lamina papyracea, and anterior ethmoidal artery canal in the setting of CRS with nasal polyps and a history of sinus surgery [35]. A sinus CT protocol that can be utilized by image guidance systems is recommended [36].

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Sinonasal Disease

Contrast-enhanced CT is not necessary to demonstrate findings of CRS or for surgical planning of paranasal sinus inflammatory disease. There is no relevant literature to support the use of combined pre- and postcontrast CT imaging. Silent sinus syndrome is atelectasis of the maxillary sinus due to intrasinus negative pressure from chronic ostial obstruction. Both CT and MRI can demonstrate decreased maxillary sinus volume and inward bowing of the sinus walls characteristic of silent sinus syndrome, but additional findings of osseous thinning, obstruction of the infundibulum, and lateralization of the uncinate process are better delineated on CT compared with MRI [37]. Nasal septal deviation can cause symptomatic nasal obstruction and can also be a risk factor for CRS. Clinical anterior rhinoscopy and endoscopic examination is the reference standard for evaluating nasal septal deviation. CT has been shown to have limited correlation with physical examination, and CT may underestimate the degree of nasal obstruction due to septal deviation at the internal nasal valve. CT therefore should not be performed solely for the evaluation of septal deviation but rather for the evaluation of any associated symptoms of CRS [38]. CTA Head There is no relevant literature to support the use of CTA head in the evaluation of CRS or for presurgical planning of paranasal sinus inflammatory disease. Sinonasal Disease FDG-PET/CT Skull Base to Mid-Thigh There is no relevant literature to support the use of FDG-PET/CT in the evaluation of CRS or for presurgical planning of paranasal sinus inflammatory disease. MRA Head There is no relevant literature to support the use of MRA head in the evaluation of CRS or for presurgical planning of paranasal sinus inflammatory disease. MRI Head There is no relevant literature to support the use of MRI head in the evaluation of CRS or for presurgical planning of paranasal sinus inflammatory disease.

Sinonasal Disease. Contrast-enhanced CT is not necessary to demonstrate findings of CRS or for surgical planning of paranasal sinus inflammatory disease. There is no relevant literature to support the use of combined pre- and postcontrast CT imaging. Silent sinus syndrome is atelectasis of the maxillary sinus due to intrasinus negative pressure from chronic ostial obstruction. Both CT and MRI can demonstrate decreased maxillary sinus volume and inward bowing of the sinus walls characteristic of silent sinus syndrome, but additional findings of osseous thinning, obstruction of the infundibulum, and lateralization of the uncinate process are better delineated on CT compared with MRI [37]. Nasal septal deviation can cause symptomatic nasal obstruction and can also be a risk factor for CRS. Clinical anterior rhinoscopy and endoscopic examination is the reference standard for evaluating nasal septal deviation. CT has been shown to have limited correlation with physical examination, and CT may underestimate the degree of nasal obstruction due to septal deviation at the internal nasal valve. CT therefore should not be performed solely for the evaluation of septal deviation but rather for the evaluation of any associated symptoms of CRS [38]. CTA Head There is no relevant literature to support the use of CTA head in the evaluation of CRS or for presurgical planning of paranasal sinus inflammatory disease. Sinonasal Disease FDG-PET/CT Skull Base to Mid-Thigh There is no relevant literature to support the use of FDG-PET/CT in the evaluation of CRS or for presurgical planning of paranasal sinus inflammatory disease. MRA Head There is no relevant literature to support the use of MRA head in the evaluation of CRS or for presurgical planning of paranasal sinus inflammatory disease. MRI Head There is no relevant literature to support the use of MRI head in the evaluation of CRS or for presurgical planning of paranasal sinus inflammatory disease.

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Sinonasal Disease

MRI Orbits, Face, and Neck MRI is not useful as the first-line study for routine sinus imaging because of the lack of bony detail. In addition, inspissated secretions may demonstrate a signal void that mimics air on T2-weighted sequences [39]. However, one study examined 89 adult patients imaged with both CT and MRI within a 3-month period for evaluation of pituitary disease and showed significant correlation between CT and MRI based Lund-Mackay staging scores of sinus disease; T1- and T2-weighted sequences were utilized for MRI scoring [40]. The utilization of IV contrast was not specified, and the Lund-Mackay scores were not correlated with patient symptoms in this study. In select cases, evaluation with MRI without and with IV contrast may be helpful to differentiate fluid secretions from inflamed mucosa and exclude an underlying obstructing mass [24]. Radiography Paranasal Sinuses Detection of mucosal thickening is limited on radiography because of overlapping osseous structures [41]. CT has largely replaced radiography given its superior depiction of sinonasal anatomy and pathology and the need for greater anatomic detail for functional endoscopic sinus surgery planning [2,41]. SPECT or SPECT/CT Paranasal Sinuses In a pilot study of 24 patients with CRS, a positive SPECT correlated with more extensive disease on CT and poor subjective response to medical treatment [42]. However, the use of SPECT remains limited in the evaluation of CRS, and this technique is generally not used in clinical practice. Variant 4: Acute sinusitis with rapid progression or suspected invasive fungal sinusitis. Initial imaging. Acute invasive fungal sinusitis is a fungal infection of the paranasal sinuses with a rapid time course of <4 weeks [4] and a high mortality rate of 50% to 80% [5,6].

Sinonasal Disease. MRI Orbits, Face, and Neck MRI is not useful as the first-line study for routine sinus imaging because of the lack of bony detail. In addition, inspissated secretions may demonstrate a signal void that mimics air on T2-weighted sequences [39]. However, one study examined 89 adult patients imaged with both CT and MRI within a 3-month period for evaluation of pituitary disease and showed significant correlation between CT and MRI based Lund-Mackay staging scores of sinus disease; T1- and T2-weighted sequences were utilized for MRI scoring [40]. The utilization of IV contrast was not specified, and the Lund-Mackay scores were not correlated with patient symptoms in this study. In select cases, evaluation with MRI without and with IV contrast may be helpful to differentiate fluid secretions from inflamed mucosa and exclude an underlying obstructing mass [24]. Radiography Paranasal Sinuses Detection of mucosal thickening is limited on radiography because of overlapping osseous structures [41]. CT has largely replaced radiography given its superior depiction of sinonasal anatomy and pathology and the need for greater anatomic detail for functional endoscopic sinus surgery planning [2,41]. SPECT or SPECT/CT Paranasal Sinuses In a pilot study of 24 patients with CRS, a positive SPECT correlated with more extensive disease on CT and poor subjective response to medical treatment [42]. However, the use of SPECT remains limited in the evaluation of CRS, and this technique is generally not used in clinical practice. Variant 4: Acute sinusitis with rapid progression or suspected invasive fungal sinusitis. Initial imaging. Acute invasive fungal sinusitis is a fungal infection of the paranasal sinuses with a rapid time course of <4 weeks [4] and a high mortality rate of 50% to 80% [5,6].

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Sinonasal Disease

Affected patients are typically immunocompromised and include patients with neutropenia, hematologic malignancies, poorly controlled diabetes, acquired immunodeficiency syndrome, and organ transplantation and patients on immunosuppressive therapy including systemic steroids and chemotherapy [4,5]. Aspergillus and Mucoraceae species are seen in most cases. Presenting symptoms are nonspecific and include fever, rhinorrhea, and diplopia, similar to those seen with ABRS. Clinicians should maintain a high index of suspicion for this diagnosis in immunocompromised patients with symptoms of ARS, orbital symptoms, and/or headache. Nasal endoscopy may demonstrate pale mucosa progressing to ulceration and necrosis [4]. Definitive diagnosis is made on biopsy with the identification of invasive fungi in the sinonasal mucosa, vessels, and bone [4]. Given the angioinvasive nature of the fungi, complications include thrombosis, dissection, and pseudoaneurysm formation of the intracranial arteries, thrombosis of the cavernous sinus, infarction, and hemorrhage [4,6]. Treatment typically includes both systemic antifungal medication and surgical debridement. Arteriography Craniofacial Arteriography may be performed for further characterization and confirmation of vascular complications of invasive fungal sinusitis detected by MRI, MRA, or CTA, including pseudoaneurysm formation, thrombosis, and dissection, although this would not be performed in the initial imaging evaluation. There is no relevant literature to support the use of arteriography in the initial evaluation of suspected acute invasive fungal sinusitis. CT Cone Beam Paranasal Sinuses CBCT is not helpful in the imaging assessment of patients with ARS with suspected orbital or intracranial complications because of the limited evaluation of the soft-tissue structures [19,25]. Sinonasal Disease CT Head CT head with IV contrast may be used to demonstrate intracranial complications but is less sensitive compared with MRI [6,23,43].

Sinonasal Disease. Affected patients are typically immunocompromised and include patients with neutropenia, hematologic malignancies, poorly controlled diabetes, acquired immunodeficiency syndrome, and organ transplantation and patients on immunosuppressive therapy including systemic steroids and chemotherapy [4,5]. Aspergillus and Mucoraceae species are seen in most cases. Presenting symptoms are nonspecific and include fever, rhinorrhea, and diplopia, similar to those seen with ABRS. Clinicians should maintain a high index of suspicion for this diagnosis in immunocompromised patients with symptoms of ARS, orbital symptoms, and/or headache. Nasal endoscopy may demonstrate pale mucosa progressing to ulceration and necrosis [4]. Definitive diagnosis is made on biopsy with the identification of invasive fungi in the sinonasal mucosa, vessels, and bone [4]. Given the angioinvasive nature of the fungi, complications include thrombosis, dissection, and pseudoaneurysm formation of the intracranial arteries, thrombosis of the cavernous sinus, infarction, and hemorrhage [4,6]. Treatment typically includes both systemic antifungal medication and surgical debridement. Arteriography Craniofacial Arteriography may be performed for further characterization and confirmation of vascular complications of invasive fungal sinusitis detected by MRI, MRA, or CTA, including pseudoaneurysm formation, thrombosis, and dissection, although this would not be performed in the initial imaging evaluation. There is no relevant literature to support the use of arteriography in the initial evaluation of suspected acute invasive fungal sinusitis. CT Cone Beam Paranasal Sinuses CBCT is not helpful in the imaging assessment of patients with ARS with suspected orbital or intracranial complications because of the limited evaluation of the soft-tissue structures [19,25]. Sinonasal Disease CT Head CT head with IV contrast may be used to demonstrate intracranial complications but is less sensitive compared with MRI [6,23,43].

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Sinonasal Disease

There is no relevant literature to support the use of noncontrast CT head or combined pre- and postcontrast CT imaging. CT Maxillofacial Noncontrast CT is effective in the evaluation of fungal sinusitis because it can demonstrate hyperattenuation in the involved sinus, bony erosions, and infiltration of the surrounding spaces [4,44]. Hyperattenuation within the paranasal sinuses can suggest the diagnosis but is nonspecific. Features including bone erosion and infiltration of the periantral fat have a high specificity but a limited sensitivity, particularly in the early phase of the disease, and severe predominantly unilateral nasal cavity mucosal thickening has a high sensitivity but low specificity [5,6,44]. In a retrospective study evaluating 42 patients with pathology-proven acute invasive fungal rhinosinusitis and 42 control patients from the same high-risk population, a 7-variable model was synthesized using infiltration of the periantral fat, pterygopalatine fossa, nasolacrimal duct and lacrimal sac, bone dehiscence, septal ulceration, and orbital involvement; positive findings in any 2 of the model variables demonstrated 88% sensitivity and 100% specificity [44]. Emphysematous soft tissue in the nasal cavity is also a specific sign of early invasive fungal sinusitis [5]. CT also enables surgical planning given its detailed depiction of sinonasal anatomy and can be used with surgical image-guidance systems when acquired with the appropriate protocol. CT with IV contrast may also be used to help demonstrate orbital and intracranial complications included in the field of view. [6,23,43]. There is no relevant literature to support the use of combined pre- and postcontrast CT imaging. CTA Head CTA head may be performed for the evaluation of vascular complications of invasive fungal sinusitis including pseudoaneurysm formation, thrombosis, and dissection, although this would not be performed in the initial imaging evaluation.

Sinonasal Disease. There is no relevant literature to support the use of noncontrast CT head or combined pre- and postcontrast CT imaging. CT Maxillofacial Noncontrast CT is effective in the evaluation of fungal sinusitis because it can demonstrate hyperattenuation in the involved sinus, bony erosions, and infiltration of the surrounding spaces [4,44]. Hyperattenuation within the paranasal sinuses can suggest the diagnosis but is nonspecific. Features including bone erosion and infiltration of the periantral fat have a high specificity but a limited sensitivity, particularly in the early phase of the disease, and severe predominantly unilateral nasal cavity mucosal thickening has a high sensitivity but low specificity [5,6,44]. In a retrospective study evaluating 42 patients with pathology-proven acute invasive fungal rhinosinusitis and 42 control patients from the same high-risk population, a 7-variable model was synthesized using infiltration of the periantral fat, pterygopalatine fossa, nasolacrimal duct and lacrimal sac, bone dehiscence, septal ulceration, and orbital involvement; positive findings in any 2 of the model variables demonstrated 88% sensitivity and 100% specificity [44]. Emphysematous soft tissue in the nasal cavity is also a specific sign of early invasive fungal sinusitis [5]. CT also enables surgical planning given its detailed depiction of sinonasal anatomy and can be used with surgical image-guidance systems when acquired with the appropriate protocol. CT with IV contrast may also be used to help demonstrate orbital and intracranial complications included in the field of view. [6,23,43]. There is no relevant literature to support the use of combined pre- and postcontrast CT imaging. CTA Head CTA head may be performed for the evaluation of vascular complications of invasive fungal sinusitis including pseudoaneurysm formation, thrombosis, and dissection, although this would not be performed in the initial imaging evaluation.

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Sinonasal Disease

There is no relevant literature to support the use of CTA head in the initial evaluation of suspected acute invasive fungal sinusitis. FDG-PET/CT Skull Base to Mid-Thigh There is no relevant literature to support the use of FDG-PET/CT in the evaluation of acute invasive fungal sinusitis. MRA Head MRA head may be performed for the evaluation of vascular complications of invasive fungal sinusitis including pseudoaneurysm formation, thrombosis, and dissection, although this would not be performed in the initial imaging evaluation. There is no relevant literature to support the use of MRA head in the initial evaluation of suspected invasive fungal sinusitis. MRI Head MRI head without and with IV contrast can delineate complications involving the intracranial compartment better than CT [5,6,43]. Combined pre- and postcontrast imaging provides the best opportunity to identify and characterize potential intracranial complications. MRI head with and without IV contrast may be complementary to CT maxillofacial to identify intracranial spread beyond the field of view of the MRI orbits, face, and neck examination. MRI Orbits, Face, and Neck A T2 signal void from fungal concretions can be confused for a pneumatized sinus, limiting evaluation of intrasinus disease with MRI [4,5]. However, MRI without and with IV contrast provides accurate evaluation of the invasion of the surrounding soft tissues, orbits, and intracranial compartment and vascular complications. One study evaluating 17 immunocompromised patients with acute invasive fungal sinusitis and 6 controls found increased sensitivity of MRI of 85% to 86% compared with CT with a sensitivity of 57% to 69% and found extrasinus invasion to be the most sensitive imaging finding [4,45]. Lack of sinonasal mucosal and nasal turbinate enhancement, the latter described as the black turbinate sign, correlates with necrosis related to the angioinvasive nature of fungal sinusitis [4].

Sinonasal Disease. There is no relevant literature to support the use of CTA head in the initial evaluation of suspected acute invasive fungal sinusitis. FDG-PET/CT Skull Base to Mid-Thigh There is no relevant literature to support the use of FDG-PET/CT in the evaluation of acute invasive fungal sinusitis. MRA Head MRA head may be performed for the evaluation of vascular complications of invasive fungal sinusitis including pseudoaneurysm formation, thrombosis, and dissection, although this would not be performed in the initial imaging evaluation. There is no relevant literature to support the use of MRA head in the initial evaluation of suspected invasive fungal sinusitis. MRI Head MRI head without and with IV contrast can delineate complications involving the intracranial compartment better than CT [5,6,43]. Combined pre- and postcontrast imaging provides the best opportunity to identify and characterize potential intracranial complications. MRI head with and without IV contrast may be complementary to CT maxillofacial to identify intracranial spread beyond the field of view of the MRI orbits, face, and neck examination. MRI Orbits, Face, and Neck A T2 signal void from fungal concretions can be confused for a pneumatized sinus, limiting evaluation of intrasinus disease with MRI [4,5]. However, MRI without and with IV contrast provides accurate evaluation of the invasion of the surrounding soft tissues, orbits, and intracranial compartment and vascular complications. One study evaluating 17 immunocompromised patients with acute invasive fungal sinusitis and 6 controls found increased sensitivity of MRI of 85% to 86% compared with CT with a sensitivity of 57% to 69% and found extrasinus invasion to be the most sensitive imaging finding [4,45]. Lack of sinonasal mucosal and nasal turbinate enhancement, the latter described as the black turbinate sign, correlates with necrosis related to the angioinvasive nature of fungal sinusitis [4].

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Sinonasal Disease

In a study from Korea evaluating 23 patients with acute invasive fungal rhinosinusitis, extrasinonasal extension was demonstrated in all cases on MRI, with orbital extension in 65%; lack of contrast enhancement was seen in 48% of patients and was found to be a prognostic factor for disease-specific mortality [46]. Although noncontrast imaging can demonstrate fluid collections and edema, combined pre- and postcontrast imaging provides the best opportunity to identify and characterize potential orbital, intracranial, and vascular complications. Sinonasal Disease Radiography Paranasal Sinuses Radiography of the paranasal sinuses is considered to be of limited usefulness given a large number of false-negative results [47]. Findings of bone erosion may be seen in advanced cases, but CT is more useful for the detection of bony erosion and adjacent soft-tissue involvement. SPECT or SPECT/CT Paranasal Sinuses There is no relevant literature to support the use of SPECT or SPECT/CT in the evaluation of acute invasive fungal sinusitis. Variant 5: Suspected sinonasal mass. Initial imaging. Patients with a sinonasal mass may present with nasal congestion, nasal fullness, anosmia, rhinorrhea, and epistaxis [8,9]. Benign lesions include papilloma, respiratory epithelial adenomatoid hamartoma, pleomorphic adenoma, juvenile nasopharyngeal angiofibroma, nerve sheath tumor, and meningioma [7,8]. The most common sinonasal malignancy is squamous cell carcinoma, with other malignancies including sinonasal undifferentiated carcinoma, adenocarcinoma, lymphoma, neuroendocrine tumors, salivary gland tumors, and melanoma [7,10]. A meningoencephalocele may also present as a sinonasal mass. Imaging may demonstrate specific features of a sinonasal mass, which can narrow a differential diagnosis and occasionally facilitate a specific diagnosis. Ultimately, very few imaging features are pathognomonic and most sinonasal neoplasms require histologic sampling for a specific diagnosis [7,24].

Sinonasal Disease. In a study from Korea evaluating 23 patients with acute invasive fungal rhinosinusitis, extrasinonasal extension was demonstrated in all cases on MRI, with orbital extension in 65%; lack of contrast enhancement was seen in 48% of patients and was found to be a prognostic factor for disease-specific mortality [46]. Although noncontrast imaging can demonstrate fluid collections and edema, combined pre- and postcontrast imaging provides the best opportunity to identify and characterize potential orbital, intracranial, and vascular complications. Sinonasal Disease Radiography Paranasal Sinuses Radiography of the paranasal sinuses is considered to be of limited usefulness given a large number of false-negative results [47]. Findings of bone erosion may be seen in advanced cases, but CT is more useful for the detection of bony erosion and adjacent soft-tissue involvement. SPECT or SPECT/CT Paranasal Sinuses There is no relevant literature to support the use of SPECT or SPECT/CT in the evaluation of acute invasive fungal sinusitis. Variant 5: Suspected sinonasal mass. Initial imaging. Patients with a sinonasal mass may present with nasal congestion, nasal fullness, anosmia, rhinorrhea, and epistaxis [8,9]. Benign lesions include papilloma, respiratory epithelial adenomatoid hamartoma, pleomorphic adenoma, juvenile nasopharyngeal angiofibroma, nerve sheath tumor, and meningioma [7,8]. The most common sinonasal malignancy is squamous cell carcinoma, with other malignancies including sinonasal undifferentiated carcinoma, adenocarcinoma, lymphoma, neuroendocrine tumors, salivary gland tumors, and melanoma [7,10]. A meningoencephalocele may also present as a sinonasal mass. Imaging may demonstrate specific features of a sinonasal mass, which can narrow a differential diagnosis and occasionally facilitate a specific diagnosis. Ultimately, very few imaging features are pathognomonic and most sinonasal neoplasms require histologic sampling for a specific diagnosis [7,24].

69502

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Sinonasal Disease

The main role of imaging in these cases is to delineate the extent of disease for treatment planning. Arteriography Craniofacial Catheter angiography is typically not useful in the initial imaging evaluation of a sinonasal mass. It may be useful for preoperative planning, preoperative embolization of a vascular mass, or to treat severe epistaxis [43,48-50]. CT Cone Beam Paranasal Sinuses CBCT is not useful in the workup of patients with sinonasal mass because of the limitations in assessing soft-tissue structures. CT Head CT best depicts osseous changes, although it is limited in determining soft-tissue and intracranial extent. Although MRI is useful for evaluating intracranial extension of a sinonasal mass, contrast-enhanced CT can also be useful for evaluating the soft-tissue and intracranial extent of the mass [51]. CT maxillofacial is useful as the first-line CT examination for suspected sinonasal mass, but contrast-enhanced CT head may be added if increased coverage of the intracranial component of a mass and its associated mass effect of the intracranial structures is required. There is no relevant literature to support the use of noncontrast CT head or combined pre- and postcontrast CT imaging. CT Maxillofacial CT best depicts osseous changes and can help distinguish bony remodeling that is more typical of slow growing or benign masses from lytic destruction seen with more aggressive malignancies [7,51]. CT can demonstrate lesion mineralization, including the osseous matrix of osteomas, the chondroid matrix of cartilaginous tumors, and the ground glass density of fibro-osseous lesions. CT also best depicts invasion of the surrounding osseous structures, although it is limited in determining soft-tissue and intracranial extent and in distinguishing tumor from sinonasal inflammation. CT and MRI are complementary imaging modalities in the evaluation of sinonasal masses, localizing and characterizing lesions and determining their extent for treatment planning.

Sinonasal Disease. The main role of imaging in these cases is to delineate the extent of disease for treatment planning. Arteriography Craniofacial Catheter angiography is typically not useful in the initial imaging evaluation of a sinonasal mass. It may be useful for preoperative planning, preoperative embolization of a vascular mass, or to treat severe epistaxis [43,48-50]. CT Cone Beam Paranasal Sinuses CBCT is not useful in the workup of patients with sinonasal mass because of the limitations in assessing soft-tissue structures. CT Head CT best depicts osseous changes, although it is limited in determining soft-tissue and intracranial extent. Although MRI is useful for evaluating intracranial extension of a sinonasal mass, contrast-enhanced CT can also be useful for evaluating the soft-tissue and intracranial extent of the mass [51]. CT maxillofacial is useful as the first-line CT examination for suspected sinonasal mass, but contrast-enhanced CT head may be added if increased coverage of the intracranial component of a mass and its associated mass effect of the intracranial structures is required. There is no relevant literature to support the use of noncontrast CT head or combined pre- and postcontrast CT imaging. CT Maxillofacial CT best depicts osseous changes and can help distinguish bony remodeling that is more typical of slow growing or benign masses from lytic destruction seen with more aggressive malignancies [7,51]. CT can demonstrate lesion mineralization, including the osseous matrix of osteomas, the chondroid matrix of cartilaginous tumors, and the ground glass density of fibro-osseous lesions. CT also best depicts invasion of the surrounding osseous structures, although it is limited in determining soft-tissue and intracranial extent and in distinguishing tumor from sinonasal inflammation. CT and MRI are complementary imaging modalities in the evaluation of sinonasal masses, localizing and characterizing lesions and determining their extent for treatment planning.

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Sinonasal Disease

If an MRI is also planned or performed, the CT can be performed without IV contrast because the main purpose of the CT is to evaluate osseous involvement. Although MRI is superior for evaluating the soft tissues, contrast-enhanced CT can also be useful for evaluating the soft-tissue and intracranial extent of the mass [51]. CT maxillofacial also enables surgical planning given its detailed depiction of sinonasal anatomy and can be used with surgical image-guidance systems when acquired with the appropriate protocol. CTA Head CTA head is typically not useful in the initial imaging evaluation of a sinonasal mass. It may be useful for preoperative planning of a vascular mass [43,48-50]. Sinonasal Disease FDG-PET/CT Skull Base to Mid-Thigh FDG-PET/CT is not useful for the initial evaluation of a sinonasal mass but can be used to detect regional and distant metastases in the staging workup of malignant neoplasms [7]. MRA Head MRA head typically is not useful in the initial imaging evaluation of a sinonasal mass. It may be useful for preoperative planning of a vascular mass [43,48-50]. MRI Head MRI head may be performed in addition to the MRI maxillofacial examination if increased coverage of the intracranial component of a mass and its associated mass effect of the intracranial structures is required. Combined pre- and postcontrast imaging provides the best opportunity to identify intracranial extension and to characterize potential intracranial complications. MRI Orbits, Face, and Neck MRI without and with IV contrast can best characterize the soft-tissue components of a mass and can occasionally demonstrate signal characteristics suggestive of specific pathology. For example, MRI can demonstrate the convoluted cerebriform pattern of inverted papillomas on T2-weighted and contrast-enhanced T1-weighted MRI; the intrinsic T1 hyperintensity of melanotic melanomas; and peritumoral intracranial cysts, which are suggestive of, but not specific for, esthesioneuroblastoma [7,8].

Sinonasal Disease. If an MRI is also planned or performed, the CT can be performed without IV contrast because the main purpose of the CT is to evaluate osseous involvement. Although MRI is superior for evaluating the soft tissues, contrast-enhanced CT can also be useful for evaluating the soft-tissue and intracranial extent of the mass [51]. CT maxillofacial also enables surgical planning given its detailed depiction of sinonasal anatomy and can be used with surgical image-guidance systems when acquired with the appropriate protocol. CTA Head CTA head is typically not useful in the initial imaging evaluation of a sinonasal mass. It may be useful for preoperative planning of a vascular mass [43,48-50]. Sinonasal Disease FDG-PET/CT Skull Base to Mid-Thigh FDG-PET/CT is not useful for the initial evaluation of a sinonasal mass but can be used to detect regional and distant metastases in the staging workup of malignant neoplasms [7]. MRA Head MRA head typically is not useful in the initial imaging evaluation of a sinonasal mass. It may be useful for preoperative planning of a vascular mass [43,48-50]. MRI Head MRI head may be performed in addition to the MRI maxillofacial examination if increased coverage of the intracranial component of a mass and its associated mass effect of the intracranial structures is required. Combined pre- and postcontrast imaging provides the best opportunity to identify intracranial extension and to characterize potential intracranial complications. MRI Orbits, Face, and Neck MRI without and with IV contrast can best characterize the soft-tissue components of a mass and can occasionally demonstrate signal characteristics suggestive of specific pathology. For example, MRI can demonstrate the convoluted cerebriform pattern of inverted papillomas on T2-weighted and contrast-enhanced T1-weighted MRI; the intrinsic T1 hyperintensity of melanotic melanomas; and peritumoral intracranial cysts, which are suggestive of, but not specific for, esthesioneuroblastoma [7,8].

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Sinonasal Disease

Decreased T2 signal and apparent diffusion coefficient correlate with increased cellularity of tumors [9]. Perfusion MRI can also potentially provide diagnostic information of sinonasal masses [52,53]. For tumor mapping, MRI is more helpful than CT for soft tissue contrast and can better distinguish tumors from the more T2 hyperintense sinus inflammatory changes and retained secretions. MRI can also best identify intracranial and perineural involvement important for staging and presurgical planning [7,24]. Compared with CT, MRI can also better detect osseous marrow invasion. CT and MRI are complementary imaging modalities in the evaluation of sinonasal masses, localizing and characterizing lesions, and determining their extent for treatment planning. Radiography Paranasal Sinuses Radiography is not considered to be part of the imaging workup of sinonasal neoplasms [51]. SPECT or SPECT/CT Paranasal Sinuses There is no relevant literature to support the use of SPECT or SPECT/CT in the evaluation of a sinonasal mass. Arteriography Craniofacial There is no relevant literature to support the use of arteriography in the evaluation of sinonasal CSF leak. CT Cone Beam Paranasal Sinuses There is no relevant literature regarding the use of CBCT paranasal sinuses in the evaluation of sinonasal CSF leak. CT Head Cisternography CT head cisternography is performed by spinal injection of intrathecal contrast, with images performed before and after contrast administration. Interval contrast pooling adjacent to an osseous defect can be identified with demonstration of a 50% or greater increase in Hounsfield units between the pre- and postcontrast scans [12]. CT head cisternography is primarily used in the setting of multiple osseous defects on high-resolution CT (HRCT) to Sinonasal Disease determine the specific site of the leak [12]. CT cisternography has a reported sensitivity of 33% to 100% and a specificity of 94% [12,13,55-58].

Sinonasal Disease. Decreased T2 signal and apparent diffusion coefficient correlate with increased cellularity of tumors [9]. Perfusion MRI can also potentially provide diagnostic information of sinonasal masses [52,53]. For tumor mapping, MRI is more helpful than CT for soft tissue contrast and can better distinguish tumors from the more T2 hyperintense sinus inflammatory changes and retained secretions. MRI can also best identify intracranial and perineural involvement important for staging and presurgical planning [7,24]. Compared with CT, MRI can also better detect osseous marrow invasion. CT and MRI are complementary imaging modalities in the evaluation of sinonasal masses, localizing and characterizing lesions, and determining their extent for treatment planning. Radiography Paranasal Sinuses Radiography is not considered to be part of the imaging workup of sinonasal neoplasms [51]. SPECT or SPECT/CT Paranasal Sinuses There is no relevant literature to support the use of SPECT or SPECT/CT in the evaluation of a sinonasal mass. Arteriography Craniofacial There is no relevant literature to support the use of arteriography in the evaluation of sinonasal CSF leak. CT Cone Beam Paranasal Sinuses There is no relevant literature regarding the use of CBCT paranasal sinuses in the evaluation of sinonasal CSF leak. CT Head Cisternography CT head cisternography is performed by spinal injection of intrathecal contrast, with images performed before and after contrast administration. Interval contrast pooling adjacent to an osseous defect can be identified with demonstration of a 50% or greater increase in Hounsfield units between the pre- and postcontrast scans [12]. CT head cisternography is primarily used in the setting of multiple osseous defects on high-resolution CT (HRCT) to Sinonasal Disease determine the specific site of the leak [12]. CT cisternography has a reported sensitivity of 33% to 100% and a specificity of 94% [12,13,55-58].

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Sinonasal Disease

The primary limitation of CT cisternography is that the patient needs to have an active CSF leak at the time of this examination for the study to be potentially diagnostic. Studies comparing CT cisternography with MRI have demonstrated CT cisternography to have a lower sensitivity of 33% to 72% versus 67% to 93% for MRI with a heavily T2-weighted sequence (MR cisternogram) and 80% for contrast-enhanced MR cisternogram [13,59,60]. CT Head Given its typical incomplete coverage of the paranasal sinuses, CT head is not typically performed for the evaluation of sinonasal CSF leak. HRCT also enables surgical planning given its detailed depiction of sinonasal anatomy and can be used with surgical image-guidance systems when acquired with the appropriate protocol. HRCT can identify the skull base defect even in the absence of an active leak; however, it is limited in identifying a specific site of the leak if the patient has multiple osseous defects because it is not clear which defect is the source of the leak [12]. A combination of HRCT and MRI with a heavily T2-weighted sequence has a reported sensitivity of 90% to 96% [13,55,61]. HRCT alone is sufficient if only 1 osseous defect is identified and corresponds with the clinical symptoms [12]. HRCT may also be the only study required in patients with iatrogenic CSF leaks for preoperative planning, because the surgical site of leak is known [12]. There is no relevant literature to support the use of contrast-enhanced CT or combined pre- and postcontrast CT in the evaluation of CSF leak. CTA Head There is no relevant literature to support the use of CTA head in the evaluation of sinonasal CSF leak. FDG-PET/CT Skull Base to Mid-Thigh There is no relevant literature to support the use of FDG-PET/CT in the evaluation of sinonasal CSF leak. MRA Head There is no relevant literature to support the use of MRA head in the evaluation of sinonasal CSF leak.

Sinonasal Disease. The primary limitation of CT cisternography is that the patient needs to have an active CSF leak at the time of this examination for the study to be potentially diagnostic. Studies comparing CT cisternography with MRI have demonstrated CT cisternography to have a lower sensitivity of 33% to 72% versus 67% to 93% for MRI with a heavily T2-weighted sequence (MR cisternogram) and 80% for contrast-enhanced MR cisternogram [13,59,60]. CT Head Given its typical incomplete coverage of the paranasal sinuses, CT head is not typically performed for the evaluation of sinonasal CSF leak. HRCT also enables surgical planning given its detailed depiction of sinonasal anatomy and can be used with surgical image-guidance systems when acquired with the appropriate protocol. HRCT can identify the skull base defect even in the absence of an active leak; however, it is limited in identifying a specific site of the leak if the patient has multiple osseous defects because it is not clear which defect is the source of the leak [12]. A combination of HRCT and MRI with a heavily T2-weighted sequence has a reported sensitivity of 90% to 96% [13,55,61]. HRCT alone is sufficient if only 1 osseous defect is identified and corresponds with the clinical symptoms [12]. HRCT may also be the only study required in patients with iatrogenic CSF leaks for preoperative planning, because the surgical site of leak is known [12]. There is no relevant literature to support the use of contrast-enhanced CT or combined pre- and postcontrast CT in the evaluation of CSF leak. CTA Head There is no relevant literature to support the use of CTA head in the evaluation of sinonasal CSF leak. FDG-PET/CT Skull Base to Mid-Thigh There is no relevant literature to support the use of FDG-PET/CT in the evaluation of sinonasal CSF leak. MRA Head There is no relevant literature to support the use of MRA head in the evaluation of sinonasal CSF leak.

69502

acrac_69502_19

Sinonasal Disease

MRI Head MRI with the inclusion of heavily T2-weighted images is often referred to as an MR cisternogram and is considered the second choice of study and should be done only in conjunction with HRCT [12,55,61]. The heavily T2-weighted sequence covering the roof of the sinonasal cavity in the coronal plane can be included in either an MRI head examination or an MRI orbits, face, and neck examination. A 3-D isotropic heavily T2-weighted sequence should be obtained to provide submillimeter high spatial and contrast resolution and allow for reformats in multiple planes. The site of the CSF leak can be demonstrated on MRI with identification of CSF extending from the subarachnoid space into the sinonasal space through an osseous defect seen on a concurrent or prior CT examination, with or without an associated cephalocele. Sensitivity of 56% to 94% and specificity of 57% to 100% have been reported Sinonasal Disease for the identification of the site of the CSF leak [12-14,55,58,61,63]. Given its superior soft-tissue contrast, MRI can also identify the contents of a cephalocele if present. MRI without IV contrast with inclusion of heavily T2-weighted images is typically sufficient for the evaluation of CSF leak. However, MRI without and with IV contrast may be useful for identifying dural enhancement and distinguishing a meningoceles from sinus secretions [11]. MRI Orbits, Face, and Neck MRI with the inclusion of heavily T2-weighted images is often referred to as an MR cisternogram and may be considered the second choice of study and should be done only in conjunction with HRCT [12,55,61]. The heavily T2-weighted sequence covering the roof of the sinonasal cavity in the coronal plane can be included in either an MRI head examination or an MRI orbits, face, and neck examination. A 3-D isotropic heavily T2-weighted sequence should be obtained to provide submillimeter high spatial and contrast resolution and to allow for reformats in multiple planes.

Sinonasal Disease. MRI Head MRI with the inclusion of heavily T2-weighted images is often referred to as an MR cisternogram and is considered the second choice of study and should be done only in conjunction with HRCT [12,55,61]. The heavily T2-weighted sequence covering the roof of the sinonasal cavity in the coronal plane can be included in either an MRI head examination or an MRI orbits, face, and neck examination. A 3-D isotropic heavily T2-weighted sequence should be obtained to provide submillimeter high spatial and contrast resolution and allow for reformats in multiple planes. The site of the CSF leak can be demonstrated on MRI with identification of CSF extending from the subarachnoid space into the sinonasal space through an osseous defect seen on a concurrent or prior CT examination, with or without an associated cephalocele. Sensitivity of 56% to 94% and specificity of 57% to 100% have been reported Sinonasal Disease for the identification of the site of the CSF leak [12-14,55,58,61,63]. Given its superior soft-tissue contrast, MRI can also identify the contents of a cephalocele if present. MRI without IV contrast with inclusion of heavily T2-weighted images is typically sufficient for the evaluation of CSF leak. However, MRI without and with IV contrast may be useful for identifying dural enhancement and distinguishing a meningoceles from sinus secretions [11]. MRI Orbits, Face, and Neck MRI with the inclusion of heavily T2-weighted images is often referred to as an MR cisternogram and may be considered the second choice of study and should be done only in conjunction with HRCT [12,55,61]. The heavily T2-weighted sequence covering the roof of the sinonasal cavity in the coronal plane can be included in either an MRI head examination or an MRI orbits, face, and neck examination. A 3-D isotropic heavily T2-weighted sequence should be obtained to provide submillimeter high spatial and contrast resolution and to allow for reformats in multiple planes.

69502

acrac_69502_20

Sinonasal Disease

The site of the CSF leak can be demonstrated on MRI with identification of CSF extending from the subarachnoid space into the sinonasal space with or without an associated cephalocele. Sensitivity of 56% to 94% and specificity of 57% to 100% have been reported for the identification of the site of the CSF leak [12- 14,55,58,61,63]. Given its superior soft-tissue contrast, MRI can also identify the contents of a cephalocele if present. MRI without IV contrast with inclusion of heavily T2-weighted images is typically sufficient for the evaluation of a CSF leak. However, MRI without and with IV contrast may be useful for identifying dural enhancement and distinguishing a meningoceles from sinus secretions [11]. Contrast-enhanced MR cisternogram is performed by spinal injection of intrathecal gadolinium, with thin-section T1-weighted images obtained before and after contrast injection. The postinjection images can be obtained immediately after contrast administration or at delayed intervals up to 24 hours after contrast administration. This technique allows for detection of both high-flow and slow-flow leaks and allows for simultaneous evaluation of cephaloceles that may be present. Sensitivity up to 100% has been reported for high-flow leaks and 60% to 70% for slow-flow leaks [12,65]. Studies have demonstrated contrast-enhanced MR cisternogram to have a higher sensitivity of 80% when compared with 33% to 72% of CT cisternogram [13,60]. Intrathecal administration of gadolinium contrast is not currently approved by the US Food and Drug Administration and requires off-label use consent [12]. Radiography Paranasal Sinuses There is no relevant literature to support the use of radiography in the evaluation of a sinonasal CSF leak. SPECT or SPECT/CT Paranasal Sinuses Three studies evaluating the efficacy of SPECT cisternography after the intrathecal injection of radiotracer reported a sensitivity of 94% with SPECT planar imaging and 94% to 100% for SPECT/CT fusion imaging for localization [13,66].

Sinonasal Disease. The site of the CSF leak can be demonstrated on MRI with identification of CSF extending from the subarachnoid space into the sinonasal space with or without an associated cephalocele. Sensitivity of 56% to 94% and specificity of 57% to 100% have been reported for the identification of the site of the CSF leak [12- 14,55,58,61,63]. Given its superior soft-tissue contrast, MRI can also identify the contents of a cephalocele if present. MRI without IV contrast with inclusion of heavily T2-weighted images is typically sufficient for the evaluation of a CSF leak. However, MRI without and with IV contrast may be useful for identifying dural enhancement and distinguishing a meningoceles from sinus secretions [11]. Contrast-enhanced MR cisternogram is performed by spinal injection of intrathecal gadolinium, with thin-section T1-weighted images obtained before and after contrast injection. The postinjection images can be obtained immediately after contrast administration or at delayed intervals up to 24 hours after contrast administration. This technique allows for detection of both high-flow and slow-flow leaks and allows for simultaneous evaluation of cephaloceles that may be present. Sensitivity up to 100% has been reported for high-flow leaks and 60% to 70% for slow-flow leaks [12,65]. Studies have demonstrated contrast-enhanced MR cisternogram to have a higher sensitivity of 80% when compared with 33% to 72% of CT cisternogram [13,60]. Intrathecal administration of gadolinium contrast is not currently approved by the US Food and Drug Administration and requires off-label use consent [12]. Radiography Paranasal Sinuses There is no relevant literature to support the use of radiography in the evaluation of a sinonasal CSF leak. SPECT or SPECT/CT Paranasal Sinuses Three studies evaluating the efficacy of SPECT cisternography after the intrathecal injection of radiotracer reported a sensitivity of 94% with SPECT planar imaging and 94% to 100% for SPECT/CT fusion imaging for localization [13,66].

69502

acrac_69339_0

Staging of Colorectal Cancer

In patients with locally advanced rectal cancer (LARC), established risk factors for poorer outcomes include circumferential resection margin involvement, extramural depth of spread >5 mm, extramural vascular invasion (EMVI), mucinous phenotype, and poor response to chemoradiotherapy (CRT) [9,10]. Multiple studies have demonstrated relatively poor compliance with adjuvant (postoperative) chemotherapy compared with neoadjuvant treatment, with decreased survival in the adjuvant (versus neoadjuvant) cohort [11]. Prospective studies have demonstrated that preoperative or neoadjuvant radiation with or without sensitizing chemotherapy reduced local recurrence risk and may increase the proportion of patients who benefit from a sphincter-saving procedure. There is an ongoing effort to assess for complete response to neoadjuvant therapy in an effort to determine which patients could potentially benefit from an organ-preservation approach without total mesorectal excision or lateral nodal dissection. aOregon Health and Science University, Portland, Oregon. bEmory University, Atlanta, Georgia. cPanel Chair, University of Wisconsin Hospital & Clinics, Madison, Wisconsin. dPanel Vice-Chair, University of California San Diego, San Diego, California. eUniversity of Texas Health Science Center at Houston and McGovern Medical School, Houston, Texas; American Gastroenterological Association. fBoston University Medical Center, Boston, Massachusetts. gH. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida. hPRiSMA Proctology Surgical Medicine & Associates, Houston, Texas; American College of Surgeons. iVirginia Tech Carilion School of Medicine, Roanoke, Virginia. jMassachusetts General Hospital, Boston, Massachusetts. kCleveland Clinic, Cleveland, Ohio. lSutter Medical Group, Sacramento, California. mDuke University Medical Center, Durham, North Carolina. nUniversity of Alabama at Birmingham, Birmingham, Alabama. oUniversity of California San Diego, San Diego, California.

Staging of Colorectal Cancer. In patients with locally advanced rectal cancer (LARC), established risk factors for poorer outcomes include circumferential resection margin involvement, extramural depth of spread >5 mm, extramural vascular invasion (EMVI), mucinous phenotype, and poor response to chemoradiotherapy (CRT) [9,10]. Multiple studies have demonstrated relatively poor compliance with adjuvant (postoperative) chemotherapy compared with neoadjuvant treatment, with decreased survival in the adjuvant (versus neoadjuvant) cohort [11]. Prospective studies have demonstrated that preoperative or neoadjuvant radiation with or without sensitizing chemotherapy reduced local recurrence risk and may increase the proportion of patients who benefit from a sphincter-saving procedure. There is an ongoing effort to assess for complete response to neoadjuvant therapy in an effort to determine which patients could potentially benefit from an organ-preservation approach without total mesorectal excision or lateral nodal dissection. aOregon Health and Science University, Portland, Oregon. bEmory University, Atlanta, Georgia. cPanel Chair, University of Wisconsin Hospital & Clinics, Madison, Wisconsin. dPanel Vice-Chair, University of California San Diego, San Diego, California. eUniversity of Texas Health Science Center at Houston and McGovern Medical School, Houston, Texas; American Gastroenterological Association. fBoston University Medical Center, Boston, Massachusetts. gH. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida. hPRiSMA Proctology Surgical Medicine & Associates, Houston, Texas; American College of Surgeons. iVirginia Tech Carilion School of Medicine, Roanoke, Virginia. jMassachusetts General Hospital, Boston, Massachusetts. kCleveland Clinic, Cleveland, Ohio. lSutter Medical Group, Sacramento, California. mDuke University Medical Center, Durham, North Carolina. nUniversity of Alabama at Birmingham, Birmingham, Alabama. oUniversity of California San Diego, San Diego, California.

69339

acrac_69339_1

Staging of Colorectal Cancer

pUniversity of California San Francisco, San Francisco, California. qEmory University, Atlanta, Georgia, Primary care physician. rSpecialty Chair, Virginia Commonwealth University Medical Center, Richmond, Virginia. The American College of Radiology seeks and encourages collaboration with other organizations on the development of the ACR Appropriateness Criteria through representation of such organizations on expert panels. Participation on the expert panel does not necessarily imply endorsement of the final document by individual contributors or their respective organization. Reprint requests to: publications@acr.org Staging of Colorectal Cancer Colon Cancer The local treatment of colon cancer relies primarily on the section of involved colon (right versus left hemicolectomy), with removal of the associated mesentery and regional nodes. Use of selective adjuvant chemotherapy is dictated by lymph node positivity and extramural lymphovascular invasion on pathologic specimen. The role of preoperative imaging to predict T stage and N stage is an area of ongoing investigation, given that neoadjuvant therapy has not yet been shown to significantly improve survival over surgery alone (with postoperative adjuvant treatment) and the standard surgical approach is radical resection. Current ongoing trials including the large randomized controlled FOxTROT trial suggest that neoadjuvant treatment can preoperatively downstage colorectal cancer with better tolerated and more complete administration of chemotherapy before surgery rather than postoperative [15]. However, preoperative imaging of colon cancer appears to be of most benefit in identifying distant metastases, regardless of its ability to predict T stage and N stage. Given the limited role of locoregional staging, the imaging variant discussion for colon cancer will be limited to evaluation of distant metastases only.

Staging of Colorectal Cancer. pUniversity of California San Francisco, San Francisco, California. qEmory University, Atlanta, Georgia, Primary care physician. rSpecialty Chair, Virginia Commonwealth University Medical Center, Richmond, Virginia. The American College of Radiology seeks and encourages collaboration with other organizations on the development of the ACR Appropriateness Criteria through representation of such organizations on expert panels. Participation on the expert panel does not necessarily imply endorsement of the final document by individual contributors or their respective organization. Reprint requests to: publications@acr.org Staging of Colorectal Cancer Colon Cancer The local treatment of colon cancer relies primarily on the section of involved colon (right versus left hemicolectomy), with removal of the associated mesentery and regional nodes. Use of selective adjuvant chemotherapy is dictated by lymph node positivity and extramural lymphovascular invasion on pathologic specimen. The role of preoperative imaging to predict T stage and N stage is an area of ongoing investigation, given that neoadjuvant therapy has not yet been shown to significantly improve survival over surgery alone (with postoperative adjuvant treatment) and the standard surgical approach is radical resection. Current ongoing trials including the large randomized controlled FOxTROT trial suggest that neoadjuvant treatment can preoperatively downstage colorectal cancer with better tolerated and more complete administration of chemotherapy before surgery rather than postoperative [15]. However, preoperative imaging of colon cancer appears to be of most benefit in identifying distant metastases, regardless of its ability to predict T stage and N stage. Given the limited role of locoregional staging, the imaging variant discussion for colon cancer will be limited to evaluation of distant metastases only.

69339

acrac_69339_2

Staging of Colorectal Cancer

Special Imaging Considerations In rectal tumors, because of the need for high-resolution anatomic detail in determining local tumor extension, the local staging of the tumor is often considered separately from the evaluation of distant metastatic disease, resulting in the need for a combination of modalities to fully stage the patient. In contrast, locoregional staging by imaging is not an issue for colon (nonrectal) cancers, and thus only the evaluation of distant metastatic disease is required. OR Discussion of Procedures by Variant Variant 1: Rectal cancer. Locoregional staging. Initial imaging. In this clinical scenario, a patient has been recently diagnosed with rectal cancer and presents for evaluation of local regional extent of the rectal cancer to determine if the person would benefit from neoadjuvant therapy before possible surgical resection. This variant excludes (nonrectal) colon cancers. For lymph node involvement, CT remains relatively nonspecific for N-stage determination. There is little agreement on the critical cut-off diameter to determine if lymph nodes are involved in the disease process. One study suggests 4.5 mm; however, nodal size is not seen as a predictor of nodal status at surgery [8,23]. Because detection of nodes involved with tumor remains a difficult problem, if a colonic resection is planned, local node groups should be encompassed in a properly performed cancer operation. Accuracies for CT detection of lymph node stage range from 56% to 84% [19,20,24-26]. Locoregional staging is not routinely performed for colon cancer; however, CT is Staging of Colorectal Cancer still useful in the initial evaluation of all patients scheduled for colorectal carcinoma surgery because of its ability to obtain a rapid global evaluation and demonstrate potential complications of the tumor (eg, perforation, obstruction) that may not be clinically apparent [18].

Staging of Colorectal Cancer. Special Imaging Considerations In rectal tumors, because of the need for high-resolution anatomic detail in determining local tumor extension, the local staging of the tumor is often considered separately from the evaluation of distant metastatic disease, resulting in the need for a combination of modalities to fully stage the patient. In contrast, locoregional staging by imaging is not an issue for colon (nonrectal) cancers, and thus only the evaluation of distant metastatic disease is required. OR Discussion of Procedures by Variant Variant 1: Rectal cancer. Locoregional staging. Initial imaging. In this clinical scenario, a patient has been recently diagnosed with rectal cancer and presents for evaluation of local regional extent of the rectal cancer to determine if the person would benefit from neoadjuvant therapy before possible surgical resection. This variant excludes (nonrectal) colon cancers. For lymph node involvement, CT remains relatively nonspecific for N-stage determination. There is little agreement on the critical cut-off diameter to determine if lymph nodes are involved in the disease process. One study suggests 4.5 mm; however, nodal size is not seen as a predictor of nodal status at surgery [8,23]. Because detection of nodes involved with tumor remains a difficult problem, if a colonic resection is planned, local node groups should be encompassed in a properly performed cancer operation. Accuracies for CT detection of lymph node stage range from 56% to 84% [19,20,24-26]. Locoregional staging is not routinely performed for colon cancer; however, CT is Staging of Colorectal Cancer still useful in the initial evaluation of all patients scheduled for colorectal carcinoma surgery because of its ability to obtain a rapid global evaluation and demonstrate potential complications of the tumor (eg, perforation, obstruction) that may not be clinically apparent [18].

69339

acrac_69339_3

Staging of Colorectal Cancer

CT Colonography Virtual colonoscopy (or CT colonography) has proven to be a valid tool in identifying both primary and synchronous colonic lesions. Limited information is available regarding the performance of CT colonography for rectal cancer staging. In a study of 45 patients with low rectal adenocarcinomas, CT colonography with multiplanar reformation demonstrated 89% accuracy for T stage [27]. FDG-PET/CT Skull Base to Mid-Thigh Limited recent information is available regarding the performance of fluorine-18-2-fluoro-2-deoxy-D-glucose (FDG)-PET/CT for local rectal cancer staging. In a study of 59 patients with rectal cancer, conventional FDG- PET/CT was found to be 73.5% accurate for T stage and to have a 64.3% sensitivity and 96.7% specificity for N stage [28]. In an evaluation of 44 pathologic and 19 control lymph nodes, the standardized uptake value (SUV)max and SUVmean were significantly higher in pathological lymph nodes than in control lymph nodes [29]. When used as a preoperative tool in advanced tumors, MRI has shown high diagnostic accuracy for both initial staging to determine surgical plan and determining resectability following neoadjuvant treatment [39-43]. Studies have shown MRI sensitivities ranging from 94% to 100% and specificities from 85% to 88% in assessment of the circumferential resection margin [44,45]. Hence, MRI is valuable in predicting complete resection with negative margins. In a multicenter cohort trial evaluating the use of high-resolution MRI with a phased-array coil in determining resectability, a total of 228 patients underwent curative-intent treatment based on the MRI characterization of tumor extent, with 95.6% of patients achieving margin-negative results [40]. High-risk MRI features (EMVI, extramural tumor depth >5 mm, T4 stage, involved circumferential resection margin) may correlate with a higher risk for distant metastases [46,47].

Staging of Colorectal Cancer. CT Colonography Virtual colonoscopy (or CT colonography) has proven to be a valid tool in identifying both primary and synchronous colonic lesions. Limited information is available regarding the performance of CT colonography for rectal cancer staging. In a study of 45 patients with low rectal adenocarcinomas, CT colonography with multiplanar reformation demonstrated 89% accuracy for T stage [27]. FDG-PET/CT Skull Base to Mid-Thigh Limited recent information is available regarding the performance of fluorine-18-2-fluoro-2-deoxy-D-glucose (FDG)-PET/CT for local rectal cancer staging. In a study of 59 patients with rectal cancer, conventional FDG- PET/CT was found to be 73.5% accurate for T stage and to have a 64.3% sensitivity and 96.7% specificity for N stage [28]. In an evaluation of 44 pathologic and 19 control lymph nodes, the standardized uptake value (SUV)max and SUVmean were significantly higher in pathological lymph nodes than in control lymph nodes [29]. When used as a preoperative tool in advanced tumors, MRI has shown high diagnostic accuracy for both initial staging to determine surgical plan and determining resectability following neoadjuvant treatment [39-43]. Studies have shown MRI sensitivities ranging from 94% to 100% and specificities from 85% to 88% in assessment of the circumferential resection margin [44,45]. Hence, MRI is valuable in predicting complete resection with negative margins. In a multicenter cohort trial evaluating the use of high-resolution MRI with a phased-array coil in determining resectability, a total of 228 patients underwent curative-intent treatment based on the MRI characterization of tumor extent, with 95.6% of patients achieving margin-negative results [40]. High-risk MRI features (EMVI, extramural tumor depth >5 mm, T4 stage, involved circumferential resection margin) may correlate with a higher risk for distant metastases [46,47].

69339

acrac_69339_4

Staging of Colorectal Cancer

In addition to initial staging prognostic features, MRI response to neoadjuvant treatment has been shown to be an indicator of long-term outcomes, including recurrence and survival [48-51]. Reduced field of view diffusion-weighted images (DWI) may demonstrate better image quality than full field of view DWIs [52]. For lymph node involvement, the differentiation of benign from metastatic locoregional nodes remains challenging. MRI is sensitive for detecting enlarged lymph nodes but remains nonspecific for differentiating benign from malignant nodes with accuracies ranging from 59% to 83% [32,36,53,54]. However, studies have shown high negative predictive value in the setting of node-negative determination by MRI, with negative predictive value ranging from 78% to 87% [32,36,53,54]. In a study of 60 patients with rectal cancer, 68.3% of patients with nodal metastasis were correctly identified using a size threshold of 7.2 mm, and accuracy was not improved by morphologic criteria [55]. However, in a study of 52 patients with rectal cancer, prediction of N stage was improved Staging of Colorectal Cancer by considering dimension, morphology, and signal characteristics [56]. Standardized reporting systems and templates have been shown to result in more complete MRI reports [57]. US Pelvis Transrectal TRUS has been considered the reference standard for T-stage evaluation of rectal carcinoma with rich historical evidence to support its use. TRUS is able to differentiate the layers of the rectal wall and provides high accuracy in detecting and characterizing tumors within the superficial layers of the rectal wall. Reported accuracies range between 80% and 97% for T-stage determination [58]. The T-stage accuracy for TRUS (84.6%) is far superior to that of CT (70.5%) [23].

Staging of Colorectal Cancer. In addition to initial staging prognostic features, MRI response to neoadjuvant treatment has been shown to be an indicator of long-term outcomes, including recurrence and survival [48-51]. Reduced field of view diffusion-weighted images (DWI) may demonstrate better image quality than full field of view DWIs [52]. For lymph node involvement, the differentiation of benign from metastatic locoregional nodes remains challenging. MRI is sensitive for detecting enlarged lymph nodes but remains nonspecific for differentiating benign from malignant nodes with accuracies ranging from 59% to 83% [32,36,53,54]. However, studies have shown high negative predictive value in the setting of node-negative determination by MRI, with negative predictive value ranging from 78% to 87% [32,36,53,54]. In a study of 60 patients with rectal cancer, 68.3% of patients with nodal metastasis were correctly identified using a size threshold of 7.2 mm, and accuracy was not improved by morphologic criteria [55]. However, in a study of 52 patients with rectal cancer, prediction of N stage was improved Staging of Colorectal Cancer by considering dimension, morphology, and signal characteristics [56]. Standardized reporting systems and templates have been shown to result in more complete MRI reports [57]. US Pelvis Transrectal TRUS has been considered the reference standard for T-stage evaluation of rectal carcinoma with rich historical evidence to support its use. TRUS is able to differentiate the layers of the rectal wall and provides high accuracy in detecting and characterizing tumors within the superficial layers of the rectal wall. Reported accuracies range between 80% and 97% for T-stage determination [58]. The T-stage accuracy for TRUS (84.6%) is far superior to that of CT (70.5%) [23].

69339

acrac_69339_5

Staging of Colorectal Cancer

Evaluation of the extent of the tumor infiltration into the mesorectum (differentiating minimal from advanced T3 tumors and minimal T3 from T2 tumors) is of clinical interest in determining the need for neoadjuvant treatment but remains a challenge for TRUS [59,60]. Although TRUS performs better than MRI for T1 tumors, similar for T2 and T3, it may be less accurate in characterizing locally advanced T4 tumors with a tendency to understage [36]. The use of TRUS in assigning patients to transanal endoscopic microsurgery versus traditional surgery remains controversial. Despite some authors reporting good accuracy for some T stages, a retrospective evaluation of the use of TRUS in patients selected to undergo transanal endoscopic microsurgery for presumed early-stage disease showed disappointing results with inaccurate staging seen in 44.8% of the 165 patients who underwent TRUS preoperatively (32.7% were understaged and 12.1% were overstaged) [61]. In a 2019 study of 500 patients, neither TRUS or MRI distinguished between T1 and T2 disease [62]. A significant limitation of TRUS is the limited field of view that compromises assessment of the relationship of the tumor, mesorectal tumor implants, tumor invasion in extramural vessels, and malignant nodes to the mesorectal fascia. MRI may better evaluate these findings because it offers a larger field of view. TRUS is also limited in its assessment of high rectal tumors. CT Abdomen and Pelvis Much of the literature on CT restaging was generated more than 5 years ago, demonstrating low accuracy for T- stage re-evaluation or assessment of complete response. CT may remain helpful in limited situations to assess for resection margin, overall decrease in tumor, or interval change in node size, and may be of benefit to assess for overall tumor susceptibility to CRT, or in rare cases to detect distant metastatic disease that has developed during the course of neoadjuvant CRT.

Staging of Colorectal Cancer. Evaluation of the extent of the tumor infiltration into the mesorectum (differentiating minimal from advanced T3 tumors and minimal T3 from T2 tumors) is of clinical interest in determining the need for neoadjuvant treatment but remains a challenge for TRUS [59,60]. Although TRUS performs better than MRI for T1 tumors, similar for T2 and T3, it may be less accurate in characterizing locally advanced T4 tumors with a tendency to understage [36]. The use of TRUS in assigning patients to transanal endoscopic microsurgery versus traditional surgery remains controversial. Despite some authors reporting good accuracy for some T stages, a retrospective evaluation of the use of TRUS in patients selected to undergo transanal endoscopic microsurgery for presumed early-stage disease showed disappointing results with inaccurate staging seen in 44.8% of the 165 patients who underwent TRUS preoperatively (32.7% were understaged and 12.1% were overstaged) [61]. In a 2019 study of 500 patients, neither TRUS or MRI distinguished between T1 and T2 disease [62]. A significant limitation of TRUS is the limited field of view that compromises assessment of the relationship of the tumor, mesorectal tumor implants, tumor invasion in extramural vessels, and malignant nodes to the mesorectal fascia. MRI may better evaluate these findings because it offers a larger field of view. TRUS is also limited in its assessment of high rectal tumors. CT Abdomen and Pelvis Much of the literature on CT restaging was generated more than 5 years ago, demonstrating low accuracy for T- stage re-evaluation or assessment of complete response. CT may remain helpful in limited situations to assess for resection margin, overall decrease in tumor, or interval change in node size, and may be of benefit to assess for overall tumor susceptibility to CRT, or in rare cases to detect distant metastatic disease that has developed during the course of neoadjuvant CRT.

69339

acrac_69339_6

Staging of Colorectal Cancer

In early studies, accuracy of CT in predicting pathological T stage after radiotherapy was low (37%) but more accurate in the identification of involved circumferential resection margin (71%) [67]. Other studies demonstrated higher accuracy of T stage, up to 61% and CT correlation with pathologic tumor regression, with frequent overstaging due to residual fibrotic change that could not be distinguished from tumor on CT [68]. Nodal involvement was difficult to assess by CT, although change in nodal size could be appreciated, with one early study demonstrating a sensitivity of 56% and a specificity of 74% for nodal involvement [69]. Staging of Colorectal Cancer More recent studies have supported these earlier conclusions, noting that CT restaging was able to document overall response versus nonresponse to neoadjuvant CRT with limited ability to predict pathologic T and N stage at surgical resection; for example, a study of 270 patients receiving CT, MRI, and US restaging revealed 45% accuracy for CT in predicting specific pT stage and 66% accuracy for pN stage [70]. Two surgical cohorts concluded that local restaging CT prompted 0% to 4% change in surgical management of LARC postneoadjuvant CRT and was mostly helpful in the setting of metastatic disease [71,72]. For lymph node involvement, like all modalities that rely primarily on size as determinant of involvement (eg, TRUS and MRI), CT remains relatively nonspecific for N-stage determination. There is little agreement on the critical cut-off diameter to determine if lymph nodes are involved in the disease process before or after neoadjuvant treatment. Nodal size is not seen as a predictor of nodal status at surgery [8,23]. Accuracies for CT detection of lymph node stage range from 56% to 84% [19,20,24-26]. CT Colonography There is no relevant literature regarding the use of CT colonography in the restaging evaluation rectal cancer postneoadjuvant CRT.

Staging of Colorectal Cancer. In early studies, accuracy of CT in predicting pathological T stage after radiotherapy was low (37%) but more accurate in the identification of involved circumferential resection margin (71%) [67]. Other studies demonstrated higher accuracy of T stage, up to 61% and CT correlation with pathologic tumor regression, with frequent overstaging due to residual fibrotic change that could not be distinguished from tumor on CT [68]. Nodal involvement was difficult to assess by CT, although change in nodal size could be appreciated, with one early study demonstrating a sensitivity of 56% and a specificity of 74% for nodal involvement [69]. Staging of Colorectal Cancer More recent studies have supported these earlier conclusions, noting that CT restaging was able to document overall response versus nonresponse to neoadjuvant CRT with limited ability to predict pathologic T and N stage at surgical resection; for example, a study of 270 patients receiving CT, MRI, and US restaging revealed 45% accuracy for CT in predicting specific pT stage and 66% accuracy for pN stage [70]. Two surgical cohorts concluded that local restaging CT prompted 0% to 4% change in surgical management of LARC postneoadjuvant CRT and was mostly helpful in the setting of metastatic disease [71,72]. For lymph node involvement, like all modalities that rely primarily on size as determinant of involvement (eg, TRUS and MRI), CT remains relatively nonspecific for N-stage determination. There is little agreement on the critical cut-off diameter to determine if lymph nodes are involved in the disease process before or after neoadjuvant treatment. Nodal size is not seen as a predictor of nodal status at surgery [8,23]. Accuracies for CT detection of lymph node stage range from 56% to 84% [19,20,24-26]. CT Colonography There is no relevant literature regarding the use of CT colonography in the restaging evaluation rectal cancer postneoadjuvant CRT.

69339

acrac_69339_7

Staging of Colorectal Cancer

FDG-PET/CT Skull Base to Mid-Thigh FDG-PET/CT has traditionally been used in initial staging of rectal cancer to further evaluate equivocal findings on CT/MRI, to definitively exclude extrahepatic metastatic disease before surgical resection/liver directed therapy, and to identify occult disease in patients with rising carcinoembryonic antigen [73,74]. It is widely considered a specific but not sensitive examination for evaluating distant rather than local disease [75]. A meta-analysis of a combined 1,262 patients with LARC in 19 studies assessed the accuracy of both local tumor restaging as well as regional nodal restaging as determined by restaging MRI compared to surgical pathology of the Circumferential resection margin (involvement or close approximation of the tumor to the mesorectal fascia) assessment may be slightly less predictive at post-CRT MRI compared with pretreatment MRI, again likely due to overstaging by post-CRT imaging [89]. Tumor height on pre- and post-CRT MRI has shown excellent correlation with endoscopic findings, however, and sphincter involvement/distance, with IV contrast MRI, is more helpful in defining the relationship to the sphincter [90,91]. Additional studies confirming that N+ patients had significantly larger nodes than N0 patients both pre- and post- CRT used size cutoff for post-CRT ypN-stage prediction of <2.5 mm and >5mm at MRI [97-99]. Conversely, with luminal tumor apparent complete response, lymph nodes over 7 mm to 8 mm have been more strongly correlated with locoregional node positive (N+) [100,101]. MRI has demonstrated 75% sensitivity and 71% specificity in determining node positive disease [93]. More recently, change in nodal size or DWI signal on restaging MRI has shown more promise in assessment of nodal disease. Lack of a lymph node signal on DWI high b value 1,000 was associated with a sensitivity of 100% and a specificity of 14% [102]; the positive predictive value was 24%, and the negative predictive value was 100%.

Staging of Colorectal Cancer. FDG-PET/CT Skull Base to Mid-Thigh FDG-PET/CT has traditionally been used in initial staging of rectal cancer to further evaluate equivocal findings on CT/MRI, to definitively exclude extrahepatic metastatic disease before surgical resection/liver directed therapy, and to identify occult disease in patients with rising carcinoembryonic antigen [73,74]. It is widely considered a specific but not sensitive examination for evaluating distant rather than local disease [75]. A meta-analysis of a combined 1,262 patients with LARC in 19 studies assessed the accuracy of both local tumor restaging as well as regional nodal restaging as determined by restaging MRI compared to surgical pathology of the Circumferential resection margin (involvement or close approximation of the tumor to the mesorectal fascia) assessment may be slightly less predictive at post-CRT MRI compared with pretreatment MRI, again likely due to overstaging by post-CRT imaging [89]. Tumor height on pre- and post-CRT MRI has shown excellent correlation with endoscopic findings, however, and sphincter involvement/distance, with IV contrast MRI, is more helpful in defining the relationship to the sphincter [90,91]. Additional studies confirming that N+ patients had significantly larger nodes than N0 patients both pre- and post- CRT used size cutoff for post-CRT ypN-stage prediction of <2.5 mm and >5mm at MRI [97-99]. Conversely, with luminal tumor apparent complete response, lymph nodes over 7 mm to 8 mm have been more strongly correlated with locoregional node positive (N+) [100,101]. MRI has demonstrated 75% sensitivity and 71% specificity in determining node positive disease [93]. More recently, change in nodal size or DWI signal on restaging MRI has shown more promise in assessment of nodal disease. Lack of a lymph node signal on DWI high b value 1,000 was associated with a sensitivity of 100% and a specificity of 14% [102]; the positive predictive value was 24%, and the negative predictive value was 100%.

69339

acrac_69339_8

Staging of Colorectal Cancer

Although the absence of nodes at DWI is not a frequent finding, it appears to be a reliable predictor of yN0 status after CRT and may support the decision to consider organ-preservation treatment. Decreased lymph node size posttreatment is significantly associated with disease-free survival [103]. US Pelvis Transrectal A significant limitation of TRUS is the limited field of view that compromises assessment of relationship of the tumor, mesorectal tumor implants, tumor invasion in extramural vessels, and malignant nodes to the mesorectal fascia. In addition, TRUS is limited in its assessment of high rectal tumors and can only be used in nonstenotic patients. Local tumor staging in a direct comparison of TRUS to MRI in 34 patients, TRUS was accurate in tumor restaging after neoadjuvant CRT in 60% to 62% and high-resolution MRI in 68% [104,105], with a meta-analysis Staging of Colorectal Cancer demonstrating lower diagnostic accuracy than MRI post-CRT, and a statistically significant decline in T-stage accuracy compared with pre-CRT [106]. Sensitivity for complete response on TRUS is as low as 25% with a specificity of 94% [107]. Contrast-enhanced TRUS plus elastography was shown in one study to improve post-CRT local staging to 85% [108]. Detection of lymph node involvement with TRUS is limited to mesorectal nodes in the immediate vicinity of the tumor, which limits sensitivity. The sensitivity pretreatment ranges from 45% to 74% [63,64], and overall accuracy ranges from 62% to 83% [22], and this appears to be similar and even more variable posttreatment [105]. Post-CRT TRUS presents the same limitations of distance from the tumor as at baseline [104]. Variant 3: Colorectal cancer. Staging for distant metastases. Initial imaging. In this clinical scenario, a patient has been recently diagnosed with colon or rectal cancer and presents for evaluation of metastatic disease in the chest, abdomen, and pelvis.

Staging of Colorectal Cancer. Although the absence of nodes at DWI is not a frequent finding, it appears to be a reliable predictor of yN0 status after CRT and may support the decision to consider organ-preservation treatment. Decreased lymph node size posttreatment is significantly associated with disease-free survival [103]. US Pelvis Transrectal A significant limitation of TRUS is the limited field of view that compromises assessment of relationship of the tumor, mesorectal tumor implants, tumor invasion in extramural vessels, and malignant nodes to the mesorectal fascia. In addition, TRUS is limited in its assessment of high rectal tumors and can only be used in nonstenotic patients. Local tumor staging in a direct comparison of TRUS to MRI in 34 patients, TRUS was accurate in tumor restaging after neoadjuvant CRT in 60% to 62% and high-resolution MRI in 68% [104,105], with a meta-analysis Staging of Colorectal Cancer demonstrating lower diagnostic accuracy than MRI post-CRT, and a statistically significant decline in T-stage accuracy compared with pre-CRT [106]. Sensitivity for complete response on TRUS is as low as 25% with a specificity of 94% [107]. Contrast-enhanced TRUS plus elastography was shown in one study to improve post-CRT local staging to 85% [108]. Detection of lymph node involvement with TRUS is limited to mesorectal nodes in the immediate vicinity of the tumor, which limits sensitivity. The sensitivity pretreatment ranges from 45% to 74% [63,64], and overall accuracy ranges from 62% to 83% [22], and this appears to be similar and even more variable posttreatment [105]. Post-CRT TRUS presents the same limitations of distance from the tumor as at baseline [104]. Variant 3: Colorectal cancer. Staging for distant metastases. Initial imaging. In this clinical scenario, a patient has been recently diagnosed with colon or rectal cancer and presents for evaluation of metastatic disease in the chest, abdomen, and pelvis.

69339

acrac_69339_9

Staging of Colorectal Cancer

CT Chest, Abdomen, and Pelvis Most studies show comparable or improved sensitivity for detection of colorectal liver metastases with IV conventional extracellular gadolinium agent-enhanced MRI compared with CT [110,111]. Abdominal/pelvic CT with IV contrast has a high negative predictive value of 90% [112]. Detection of possible lung metastases is also an important part of the initial imaging evaluation of patients with colorectal carcinoma. The National Comprehensive Cancer Network recommends that patients with newly diagnosed colorectal cancer undergo staging chest CT, because staging chest CT has been shown to detect more lung metastases than chest radiography [119]. In a series of 74 patients with newly diagnosed rectal cancer who underwent both chest CT and chest radiography, 37% of patients with a normal chest radiograph had a lesion visible only on the chest CT, and 17% of these patients were found to have at least one pulmonary metastasis [119]. Among patients with potentially resectable liver metastases and a negative initial chest PET, additional imaging with a chest CT revealed pulmonary metastases in 5% of patients [120]. A potential pitfall of chest CT is the detection of small indeterminate pulmonary nodules that are not metastases [121]. In another study, approximately one-fourth of the indeterminate lesions on preoperative CT ultimately developed into metastases and 1 in 10 into other lung malignancies [122]. Chest CT examinations performed to evaluate for pulmonary metastases were typically performed with IV contrast material [121,123,124]. FDG-PET/CT Skull Base to Mid-Thigh Although there is some evidence to support the use of PET/CT in the local staging of patients with rectal carcinoma, the more common clinical application of PET/CT is in identifying nodal and distant metastases [125-127].

Staging of Colorectal Cancer. CT Chest, Abdomen, and Pelvis Most studies show comparable or improved sensitivity for detection of colorectal liver metastases with IV conventional extracellular gadolinium agent-enhanced MRI compared with CT [110,111]. Abdominal/pelvic CT with IV contrast has a high negative predictive value of 90% [112]. Detection of possible lung metastases is also an important part of the initial imaging evaluation of patients with colorectal carcinoma. The National Comprehensive Cancer Network recommends that patients with newly diagnosed colorectal cancer undergo staging chest CT, because staging chest CT has been shown to detect more lung metastases than chest radiography [119]. In a series of 74 patients with newly diagnosed rectal cancer who underwent both chest CT and chest radiography, 37% of patients with a normal chest radiograph had a lesion visible only on the chest CT, and 17% of these patients were found to have at least one pulmonary metastasis [119]. Among patients with potentially resectable liver metastases and a negative initial chest PET, additional imaging with a chest CT revealed pulmonary metastases in 5% of patients [120]. A potential pitfall of chest CT is the detection of small indeterminate pulmonary nodules that are not metastases [121]. In another study, approximately one-fourth of the indeterminate lesions on preoperative CT ultimately developed into metastases and 1 in 10 into other lung malignancies [122]. Chest CT examinations performed to evaluate for pulmonary metastases were typically performed with IV contrast material [121,123,124]. FDG-PET/CT Skull Base to Mid-Thigh Although there is some evidence to support the use of PET/CT in the local staging of patients with rectal carcinoma, the more common clinical application of PET/CT is in identifying nodal and distant metastases [125-127].

69339

acrac_69339_10

Staging of Colorectal Cancer

PET/CT is useful for determining overall stage and identifying patients with metastatic disease (sensitivity of 89% and specificity of 64%); however, the accuracy on a lesion-by-lesion basis is relatively low compared with contrast- enhanced CT and MRI for liver metastases (55% versus 89% in a study comparing PET/CT to MDCT) [128,129]. PET/CT may help to exclude other sites of disease beyond the liver or, in complex cases, to improve staging accuracy in which it has been shown to result in a change in management in up to 8% to 11% of patients [128,130- 132]. Caution should be exercised, however, as the findings of PET/CT may be nonspecific and could result in a negative impact on patient care in up to 9% of patients [128]. Additionally, PET/CT has further reduced sensitivity Staging of Colorectal Cancer for lesions in the setting of neoadjuvant therapy and should be used in conjunction with IV contrast CT or MRI for presurgical planning of liver metastases [133]. PET/CT may add influence in the positive predictive value of avid lymph nodes because it has a higher specificity than other modalities. The sensitivity of detecting nodal metastases is only 43% with a specificity of 80%, and again size is not a helpful characteristic. Because of limited sensitivity of MRI for lung nodules, a chest CT can be utilized in addition to abdominal MRI for complete staging. The National Comprehensive Cancer Network recommends that patients with newly diagnosed colorectal cancer undergo staging chest CT, because staging chest CT has been shown to detect more lung metastases than chest radiography [119]. In a series of 74 patients with newly diagnosed rectal cancer who underwent both chest CT and chest radiography, 37% of patients with a normal chest radiograph had a lesion visible only on the chest CT, and 17% of these patients were found to have at least one pulmonary metastasis [119].

Staging of Colorectal Cancer. PET/CT is useful for determining overall stage and identifying patients with metastatic disease (sensitivity of 89% and specificity of 64%); however, the accuracy on a lesion-by-lesion basis is relatively low compared with contrast- enhanced CT and MRI for liver metastases (55% versus 89% in a study comparing PET/CT to MDCT) [128,129]. PET/CT may help to exclude other sites of disease beyond the liver or, in complex cases, to improve staging accuracy in which it has been shown to result in a change in management in up to 8% to 11% of patients [128,130- 132]. Caution should be exercised, however, as the findings of PET/CT may be nonspecific and could result in a negative impact on patient care in up to 9% of patients [128]. Additionally, PET/CT has further reduced sensitivity Staging of Colorectal Cancer for lesions in the setting of neoadjuvant therapy and should be used in conjunction with IV contrast CT or MRI for presurgical planning of liver metastases [133]. PET/CT may add influence in the positive predictive value of avid lymph nodes because it has a higher specificity than other modalities. The sensitivity of detecting nodal metastases is only 43% with a specificity of 80%, and again size is not a helpful characteristic. Because of limited sensitivity of MRI for lung nodules, a chest CT can be utilized in addition to abdominal MRI for complete staging. The National Comprehensive Cancer Network recommends that patients with newly diagnosed colorectal cancer undergo staging chest CT, because staging chest CT has been shown to detect more lung metastases than chest radiography [119]. In a series of 74 patients with newly diagnosed rectal cancer who underwent both chest CT and chest radiography, 37% of patients with a normal chest radiograph had a lesion visible only on the chest CT, and 17% of these patients were found to have at least one pulmonary metastasis [119].

69339

acrac_71095_0

Suspected Pulmonary Hypertension

Diagnosis of PH remains challenging because of the diverse group of diseases that can cause PH as well as its nonspecific symptoms. Signs and symptoms of PH include dyspnea, fatigue, palpitations, angina, peripheral edema, hepatomegaly, ascites, syncope, and, rarely, unilateral vocal cord paralysis [4,10]. A careful history evaluation is critical to evaluate for risk factors for PH, including family history, history of drugs and toxins associated with PH, collagen vascular disease, human immunodeficiency virus (HIV), portal hypertension, congenital or left heart disease, and venous thromboembolic disease. Clinical evaluation includes pulmonary function tests, arterial blood gases, routine biochemistry, hematology, thyroid function, and serological testing to evaluate for lung disease, liver disease, connective tissue disorders, and HIV, as well as cardiothoracic imaging [10,11]. The American College of Radiology seeks and encourages collaboration with other organizations on the development of the ACR Appropriateness Criteria through representation of such organizations on expert panels. Participation on the expert panel does not necessarily imply endorsement of the final document by individual contributors or their respective organization. Reprint requests to: publications@acr.org Suspected Pulmonary Hypertension All elements are essential: 1) timing, 2) reconstructions/reformats, and 3) 3-D renderings. Standard CTs with contrast also include timing issues and reconstructions/reformats. Only in CTA, however, is 3-D rendering a required element. This corresponds to the definitions that the CMS has applied to the Current Procedural Terminology codes. OR Discussion of Procedures by Variant Variant 1: Suspected pulmonary hypertension. Initial imaging. Radiography Chest PH tends to present with nonspecific symptoms; thus, chest radiography is often the first imaging test performed [11].

Suspected Pulmonary Hypertension. Diagnosis of PH remains challenging because of the diverse group of diseases that can cause PH as well as its nonspecific symptoms. Signs and symptoms of PH include dyspnea, fatigue, palpitations, angina, peripheral edema, hepatomegaly, ascites, syncope, and, rarely, unilateral vocal cord paralysis [4,10]. A careful history evaluation is critical to evaluate for risk factors for PH, including family history, history of drugs and toxins associated with PH, collagen vascular disease, human immunodeficiency virus (HIV), portal hypertension, congenital or left heart disease, and venous thromboembolic disease. Clinical evaluation includes pulmonary function tests, arterial blood gases, routine biochemistry, hematology, thyroid function, and serological testing to evaluate for lung disease, liver disease, connective tissue disorders, and HIV, as well as cardiothoracic imaging [10,11]. The American College of Radiology seeks and encourages collaboration with other organizations on the development of the ACR Appropriateness Criteria through representation of such organizations on expert panels. Participation on the expert panel does not necessarily imply endorsement of the final document by individual contributors or their respective organization. Reprint requests to: publications@acr.org Suspected Pulmonary Hypertension All elements are essential: 1) timing, 2) reconstructions/reformats, and 3) 3-D renderings. Standard CTs with contrast also include timing issues and reconstructions/reformats. Only in CTA, however, is 3-D rendering a required element. This corresponds to the definitions that the CMS has applied to the Current Procedural Terminology codes. OR Discussion of Procedures by Variant Variant 1: Suspected pulmonary hypertension. Initial imaging. Radiography Chest PH tends to present with nonspecific symptoms; thus, chest radiography is often the first imaging test performed [11].

71095

acrac_71095_1

Suspected Pulmonary Hypertension

Multiple historic studies have shown that chest radiography is a useful study in the initial evaluation of PH [13-19]. Miniati et al [20] found that chest radiography has a high sensitivity (96.9%) and specificity (99.1%) for detection of moderate to severe PH. Additionally, chest radiography can show findings of diffuse lung diseases that can be associated with PH, such as interstitial fibrosis and emphysema [10,13]. Although chest radiography does well in detecting the presence/absence of PH in moderate and severe cases of PH, it performs poorly in estimating the PH severity [14]. Additionally, it is known to be insensitive in the detection of mild PH. Thus, a normal chest radiograph does not exclude PH, and further imaging evaluation should be pursued if there are persistent unexplained symptoms such as dyspnea or risk factors for PH [13,15,17,20,21]. Findings of PH on chest radiography include enlargement of the central pulmonary arteries, with or without rapid tapering (pruning), and right heart chamber enlargement [10,17,19,21]. A study by Schmidt et al [17] found that the main PA (MPA) was enlarged (>35 mm from midline to left lateral border of the PA on posterior anterior radiograph) 96% of the time in PH. A measurement of the right descending PA >15 mm in women (>16 mm in men) at the hilum on a posterior anterior view has good sensitivity, specificity, and accuracy for PH (93%, 88%, and 92%, respectively) and is considered to be a very useful finding [16-18]. A diameter of the left descending PA >18 mm on the lateral view is also suggestive of PH, but although it has good sensitivity (93%), the specificity (67%) and accuracy (87%) are poorer [16]. Other studies, such as that of Schmidt et al [17], have found poorer sensitivity for the left descending PA measurement. Miniati et al [20] found the most prevalent radiographic findings in patients with PH were enlarged MPA (97%), enlarged right ventricle (95%), and enlarged right descending PA (93%).

Suspected Pulmonary Hypertension. Multiple historic studies have shown that chest radiography is a useful study in the initial evaluation of PH [13-19]. Miniati et al [20] found that chest radiography has a high sensitivity (96.9%) and specificity (99.1%) for detection of moderate to severe PH. Additionally, chest radiography can show findings of diffuse lung diseases that can be associated with PH, such as interstitial fibrosis and emphysema [10,13]. Although chest radiography does well in detecting the presence/absence of PH in moderate and severe cases of PH, it performs poorly in estimating the PH severity [14]. Additionally, it is known to be insensitive in the detection of mild PH. Thus, a normal chest radiograph does not exclude PH, and further imaging evaluation should be pursued if there are persistent unexplained symptoms such as dyspnea or risk factors for PH [13,15,17,20,21]. Findings of PH on chest radiography include enlargement of the central pulmonary arteries, with or without rapid tapering (pruning), and right heart chamber enlargement [10,17,19,21]. A study by Schmidt et al [17] found that the main PA (MPA) was enlarged (>35 mm from midline to left lateral border of the PA on posterior anterior radiograph) 96% of the time in PH. A measurement of the right descending PA >15 mm in women (>16 mm in men) at the hilum on a posterior anterior view has good sensitivity, specificity, and accuracy for PH (93%, 88%, and 92%, respectively) and is considered to be a very useful finding [16-18]. A diameter of the left descending PA >18 mm on the lateral view is also suggestive of PH, but although it has good sensitivity (93%), the specificity (67%) and accuracy (87%) are poorer [16]. Other studies, such as that of Schmidt et al [17], have found poorer sensitivity for the left descending PA measurement. Miniati et al [20] found the most prevalent radiographic findings in patients with PH were enlarged MPA (97%), enlarged right ventricle (95%), and enlarged right descending PA (93%).

71095

acrac_71095_2

Suspected Pulmonary Hypertension

US Echocardiography Transthoracic Resting Transthoracic Doppler echocardiography is a noninvasive test that is a useful part of the initial evaluation of suspected PH [22]. A recent meta-analysis by Ni et al [23] showed that, overall, it has good sensitivity and fair specificity (85% and 74%, respectively) for detecting moderate to severe PH. However, it does not perform as well in detecting mild PH, particularly cases of PH secondary to lung diseases. Transthoracic Doppler echocardiography uses continuous wave Doppler to measure the peak tricuspid regurgitation velocity, which is used in combination with various echocardiographic signs suggestive of PH to assign a low, intermediate, or high echocardiographic probability of PH [24-26]. Echocardiographic signs suggestive of PH fall into 3 categories: right ventricular (RV) findings, PA findings, and inferior vena cava (IVC)/right atrial (RA) findings. RV findings include RV/left ventricular (LV) basal diameter ratio >1 and flattening of the interventricular septum. PA findings include PA diameter >25 mm, early diastolic Transthoracic Doppler echocardiography is also useful in the assessment of multiple right heart parameters that are influenced by PH, including RA and RV size, RV systolic function, RV strain, tricuspid annular plane systolic excursion, and biventricular index. A biventricular index (RV end-diastolic area to LV end-diastolic area) >0.93 is associated with an increased risk of death in patients with PH [22,27]. The presence of pericardial effusion as well as valvular morphology and function are also easily assessed by echocardiography. An echocardiographic bubble study using agitated saline can be performed during the examination to assess for intracardiac shunts [11]. Studies have shown that real-time 3-D echocardiography evaluates RV volumes and the ejection fraction more accurately than conventional 2-D echocardiography [28].

Suspected Pulmonary Hypertension. US Echocardiography Transthoracic Resting Transthoracic Doppler echocardiography is a noninvasive test that is a useful part of the initial evaluation of suspected PH [22]. A recent meta-analysis by Ni et al [23] showed that, overall, it has good sensitivity and fair specificity (85% and 74%, respectively) for detecting moderate to severe PH. However, it does not perform as well in detecting mild PH, particularly cases of PH secondary to lung diseases. Transthoracic Doppler echocardiography uses continuous wave Doppler to measure the peak tricuspid regurgitation velocity, which is used in combination with various echocardiographic signs suggestive of PH to assign a low, intermediate, or high echocardiographic probability of PH [24-26]. Echocardiographic signs suggestive of PH fall into 3 categories: right ventricular (RV) findings, PA findings, and inferior vena cava (IVC)/right atrial (RA) findings. RV findings include RV/left ventricular (LV) basal diameter ratio >1 and flattening of the interventricular septum. PA findings include PA diameter >25 mm, early diastolic Transthoracic Doppler echocardiography is also useful in the assessment of multiple right heart parameters that are influenced by PH, including RA and RV size, RV systolic function, RV strain, tricuspid annular plane systolic excursion, and biventricular index. A biventricular index (RV end-diastolic area to LV end-diastolic area) >0.93 is associated with an increased risk of death in patients with PH [22,27]. The presence of pericardial effusion as well as valvular morphology and function are also easily assessed by echocardiography. An echocardiographic bubble study using agitated saline can be performed during the examination to assess for intracardiac shunts [11]. Studies have shown that real-time 3-D echocardiography evaluates RV volumes and the ejection fraction more accurately than conventional 2-D echocardiography [28].

71095

acrac_71095_3

Suspected Pulmonary Hypertension

In addition, pressure gradient-volume diagrams derived from 3-D echocardiography data can be used to reliably estimate RV stroke work in patients with PH [29]. Populations including those with a known genetic mutation associated with PAH, first degree relative with PAH, scleroderma spectrum, congenital heart disease, and portal hypertension before liver transplant are at high risk of developing PAH and may benefit from screening with echocardiography [30]. Patients with a high echocardiographic probability for PH have poorer postsurgical outcomes; thus, PH echocardiographic probability can also be used to risk stratify patients with risk factors for PH before a procedure/surgery [27,31]. As mentioned above, transthoracic Doppler echocardiography will not reliably detect mild, asymptomatic PH. Further evaluation with additional noninvasive examinations including CT and MRI may be obtained if there is persistent, high clinical suspicion for PH. RHC is also useful for further evaluation [10,24]. V/Q Scan Lung There are no data to suggest ventilation-perfusion (V/Q) scintigraphy as an initial test in the workup of suspected PH. However, current guidelines recommend V/Q scintigraphy of the lungs in all patients with unexplained PH to assess for CTEPH [24]. Identification of CTEPH is important because it allows for potentially curative surgical therapy [33]. V/Q scintigraphy typically shows mismatched wedge-shaped, segmental defects in the setting of CTEPH that can normalize after surgical treatment [34]. The high sensitivity and specificity of V/Q scintigraphy is useful for CTEPH detection [34]. A recent study by Mehari et al [35] comparing V/Q scintigraphy and multidetector CT pulmonary angiography (CTPA) for CTEPH detection found that V/Q scintigraphy had excellent sensitivity (90%) and good specificity (75%), whereas CTPA suffered from poor sensitivity (37%), although it had excellent specificity (100%).

Suspected Pulmonary Hypertension. In addition, pressure gradient-volume diagrams derived from 3-D echocardiography data can be used to reliably estimate RV stroke work in patients with PH [29]. Populations including those with a known genetic mutation associated with PAH, first degree relative with PAH, scleroderma spectrum, congenital heart disease, and portal hypertension before liver transplant are at high risk of developing PAH and may benefit from screening with echocardiography [30]. Patients with a high echocardiographic probability for PH have poorer postsurgical outcomes; thus, PH echocardiographic probability can also be used to risk stratify patients with risk factors for PH before a procedure/surgery [27,31]. As mentioned above, transthoracic Doppler echocardiography will not reliably detect mild, asymptomatic PH. Further evaluation with additional noninvasive examinations including CT and MRI may be obtained if there is persistent, high clinical suspicion for PH. RHC is also useful for further evaluation [10,24]. V/Q Scan Lung There are no data to suggest ventilation-perfusion (V/Q) scintigraphy as an initial test in the workup of suspected PH. However, current guidelines recommend V/Q scintigraphy of the lungs in all patients with unexplained PH to assess for CTEPH [24]. Identification of CTEPH is important because it allows for potentially curative surgical therapy [33]. V/Q scintigraphy typically shows mismatched wedge-shaped, segmental defects in the setting of CTEPH that can normalize after surgical treatment [34]. The high sensitivity and specificity of V/Q scintigraphy is useful for CTEPH detection [34]. A recent study by Mehari et al [35] comparing V/Q scintigraphy and multidetector CT pulmonary angiography (CTPA) for CTEPH detection found that V/Q scintigraphy had excellent sensitivity (90%) and good specificity (75%), whereas CTPA suffered from poor sensitivity (37%), although it had excellent specificity (100%).

71095

acrac_71095_4

Suspected Pulmonary Hypertension

This is comparable to a prior study by Tunariu et al [36], which found that V/Q scintigraphy was more sensitive than multidetector CTPA in detecting chronic thromboembolic pulmonary disease amenable to surgery, with V/Q scans demonstrating a sensitivity of 96% to 97% and a specificity of 90% to 95% compared with a sensitivity of 51% and specificity of 99% for multidetector CTPA. However, a study that compared V/Q scanning versus CTPA by He et al [37] showed both techniques had good sensitivity, specificity, and accuracy at a center with significant CTEPH experience (100% versus 92%, 94% versus 95%, and 97% versus 94%, respectively). Compared with planar V/Q scanning, V/Q single-photon emission CT improves sensitivity and specificity, resulting in an accuracy of 94% [38]. The slightly lower specificity of V/Q scintigraphy relative to multidetector CTPA is secondary in patients with idiopathic Suspected Pulmonary Hypertension PAH (IPAH) in whom abnormal V/Q scans can also be demonstrated whom can also demonstrate abnormal V/Q scans [33,38]. Although V/Q scintigraphy has excellent sensitivity for CTEPH, its greatest power lies with its negative predictive value. A normal or low-probability scan essentially excludes the diagnosis of CTEPH, although the V/Q scan may be normal in other causes of PH [10,24,33]. CT Chest CT chest is another noninvasive technique that can assess for PH. CT chest can be performed with or without intravenous (IV) contrast but is ideally performed with IV contrast to adequately visualize the pulmonary vasculature. CT chest without IV contrast is not a first-line test for suspected PH but may be useful to help look for etiologies of PH in patients who already hold a diagnosis of PH. There are no data support obtaining a CT chest with and without IV contrast in the setting of suspected PH.

Suspected Pulmonary Hypertension. This is comparable to a prior study by Tunariu et al [36], which found that V/Q scintigraphy was more sensitive than multidetector CTPA in detecting chronic thromboembolic pulmonary disease amenable to surgery, with V/Q scans demonstrating a sensitivity of 96% to 97% and a specificity of 90% to 95% compared with a sensitivity of 51% and specificity of 99% for multidetector CTPA. However, a study that compared V/Q scanning versus CTPA by He et al [37] showed both techniques had good sensitivity, specificity, and accuracy at a center with significant CTEPH experience (100% versus 92%, 94% versus 95%, and 97% versus 94%, respectively). Compared with planar V/Q scanning, V/Q single-photon emission CT improves sensitivity and specificity, resulting in an accuracy of 94% [38]. The slightly lower specificity of V/Q scintigraphy relative to multidetector CTPA is secondary in patients with idiopathic Suspected Pulmonary Hypertension PAH (IPAH) in whom abnormal V/Q scans can also be demonstrated whom can also demonstrate abnormal V/Q scans [33,38]. Although V/Q scintigraphy has excellent sensitivity for CTEPH, its greatest power lies with its negative predictive value. A normal or low-probability scan essentially excludes the diagnosis of CTEPH, although the V/Q scan may be normal in other causes of PH [10,24,33]. CT Chest CT chest is another noninvasive technique that can assess for PH. CT chest can be performed with or without intravenous (IV) contrast but is ideally performed with IV contrast to adequately visualize the pulmonary vasculature. CT chest without IV contrast is not a first-line test for suspected PH but may be useful to help look for etiologies of PH in patients who already hold a diagnosis of PH. There are no data support obtaining a CT chest with and without IV contrast in the setting of suspected PH.

71095

acrac_71095_5

Suspected Pulmonary Hypertension

In addition to demonstrating findings suggestive of PH, chest CT can also characterize various pulmonary etiologies that cause PH, including IPAH, pulmonary capillary hemangiomatosis (PCH), pulmonary veno-occlusive disease (PVOD), and many diffuse lung diseases. IPAH is characterized by plexiform lesions, which are networks of capillary-like channels in the wall of a dilated muscular PA that appear as ground glass centrilobular nodules. IPAH findings on CT include dilated central pulmonary arteries, centrilobular ground glass nodules associated with enlarged tortuous centrilobular arterioles, and pericardial effusion [21,46]. PCH, a diffuse proliferation of capillaries in the pulmonary interstitium, and PVOD, a disease of pulmonary venous hypertension secondary to pulmonary vein intimal fibrosis and subsequent venous occlusion, are rare diseases whose diagnosis can be suggested by findings on CT. On CT, PCH will have enlarged pulmonary arteries, centrilobular ground glass nodules, and interlobular septal thickening. PVOD presents on CT with enlarged pulmonary arteries, lymphadenopathy, pleural effusion, and interlobular septal thickening in the setting of a normal size left atrium. Surgical biopsy is necessary to confirm the diagnosis of PCH and PVOD [46-48]. Suspected Pulmonary Hypertension uncommon finding in PH, has also been reported at CTA [52,53]. As with chest CT, evaluation with RHC remains necessary to confirm PH suspected on CTPA before initiating therapy [24]. MRI Heart Function and Morphology MRI can also noninvasively assess the MPA and right ventricle for PH with good sensitivity and specificity (92% and 80%, respectively) and is useful for RV morphology and function assessment.

Suspected Pulmonary Hypertension. In addition to demonstrating findings suggestive of PH, chest CT can also characterize various pulmonary etiologies that cause PH, including IPAH, pulmonary capillary hemangiomatosis (PCH), pulmonary veno-occlusive disease (PVOD), and many diffuse lung diseases. IPAH is characterized by plexiform lesions, which are networks of capillary-like channels in the wall of a dilated muscular PA that appear as ground glass centrilobular nodules. IPAH findings on CT include dilated central pulmonary arteries, centrilobular ground glass nodules associated with enlarged tortuous centrilobular arterioles, and pericardial effusion [21,46]. PCH, a diffuse proliferation of capillaries in the pulmonary interstitium, and PVOD, a disease of pulmonary venous hypertension secondary to pulmonary vein intimal fibrosis and subsequent venous occlusion, are rare diseases whose diagnosis can be suggested by findings on CT. On CT, PCH will have enlarged pulmonary arteries, centrilobular ground glass nodules, and interlobular septal thickening. PVOD presents on CT with enlarged pulmonary arteries, lymphadenopathy, pleural effusion, and interlobular septal thickening in the setting of a normal size left atrium. Surgical biopsy is necessary to confirm the diagnosis of PCH and PVOD [46-48]. Suspected Pulmonary Hypertension uncommon finding in PH, has also been reported at CTA [52,53]. As with chest CT, evaluation with RHC remains necessary to confirm PH suspected on CTPA before initiating therapy [24]. MRI Heart Function and Morphology MRI can also noninvasively assess the MPA and right ventricle for PH with good sensitivity and specificity (92% and 80%, respectively) and is useful for RV morphology and function assessment.

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Suspected Pulmonary Hypertension

RV functional abnormalities secondary to PH-related cardiac remodeling include RV hypokinesis, leftward bowing and/or paradoxical movement of the interventricular septum, RV dysfunction (increased end-diastolic volume, reduced ejection fraction, reduced cardiac index, reduced stroke volume), and pulmonary and tricuspid insufficiency [59-62]. RV mass and LV mass can also be accurately determined, which can then be used to calculate a ventricular mass index (RV mass/LV mass), with a ratio >0.6 being abnormal [61,63,64]. Cardiac MRI shows many of the morphologic changes of PH that are also depicted by chest CT and CTPA: PA enlargement, MPA to adjacent ascending aorta ratio > 1, RV enlargement and hypertrophy, straightening of the interventricular septum, and pericardial thickening and effusion [61,65,66]. Measured parameters of RV ejection fraction, RV end diastolic volume, and RV-PA coupling metrics measured on cardiac MR have been shown to be important prognostic indicators of PH [59,65]. Additional characteristic findings of PH on cardiac MRI include findings on late gadolinium enhancement, T1 mapping, and phase-contrast sequences. Enhancement of the RV insertion points on late gadolinium enhancement imaging is commonly present in individuals with PH and is compatible with fibrosis related to RV stress [60,62,63,67]. T1 mapping will also show abnormally prolonged values at the RV insertion points in PH [68,69]. Cardiac MRI phase-contrast imaging techniques can measure average blood flow velocity of the MPA, which correlates with mPAP. Patients with PH have sluggish PA flow as demonstrated by prolonged acceleration times on phase-contrast imaging. Severity of tricuspid regurgitation can be accurately quantified with 2-D phase-contrast imaging and used to estimate MPA pressure [65,70,71].

Suspected Pulmonary Hypertension. RV functional abnormalities secondary to PH-related cardiac remodeling include RV hypokinesis, leftward bowing and/or paradoxical movement of the interventricular septum, RV dysfunction (increased end-diastolic volume, reduced ejection fraction, reduced cardiac index, reduced stroke volume), and pulmonary and tricuspid insufficiency [59-62]. RV mass and LV mass can also be accurately determined, which can then be used to calculate a ventricular mass index (RV mass/LV mass), with a ratio >0.6 being abnormal [61,63,64]. Cardiac MRI shows many of the morphologic changes of PH that are also depicted by chest CT and CTPA: PA enlargement, MPA to adjacent ascending aorta ratio > 1, RV enlargement and hypertrophy, straightening of the interventricular septum, and pericardial thickening and effusion [61,65,66]. Measured parameters of RV ejection fraction, RV end diastolic volume, and RV-PA coupling metrics measured on cardiac MR have been shown to be important prognostic indicators of PH [59,65]. Additional characteristic findings of PH on cardiac MRI include findings on late gadolinium enhancement, T1 mapping, and phase-contrast sequences. Enhancement of the RV insertion points on late gadolinium enhancement imaging is commonly present in individuals with PH and is compatible with fibrosis related to RV stress [60,62,63,67]. T1 mapping will also show abnormally prolonged values at the RV insertion points in PH [68,69]. Cardiac MRI phase-contrast imaging techniques can measure average blood flow velocity of the MPA, which correlates with mPAP. Patients with PH have sluggish PA flow as demonstrated by prolonged acceleration times on phase-contrast imaging. Severity of tricuspid regurgitation can be accurately quantified with 2-D phase-contrast imaging and used to estimate MPA pressure [65,70,71].

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Suspected Pulmonary Hypertension

More recently, 4-D flow has been used to assess the MPA and detect the hemodynamic alterations that occur with PH: decreased wall shear stress, increased tricuspid regurgitation velocity, and abnormal vortex blood flow pattern within the MPA that is associated with early-onset systolic retrograde flow [65,72-74]. MRA Chest Pulmonary MR angiography (MRA) shows morphologic changes of PH that are also depicted by MRI heart and CT/CTPA: PA enlargement, MPA to adjacent ascending aorta ratio >1, RV enlargement and hypertrophy, straightening of the interventricular septum, and pericardial thickening and effusion [61,65,66]. MRA has lower sensitivity for the detection of acute and chronic pulmonary embolism compared with CTPA [61]. There are no data to support the use of MRA chest alone as a first-line test for suspected PH; however, the combination of MRA Catheterization Right Heart RHC is an invasive procedure that defines cardiopulmonary hemodynamics and is performed after all noninvasive examinations have been completed to confirm the diagnosis of PH before initiating treatment per current guidelines [24]. RHC directly measures the PAP to confirm the diagnosis of PH as well as the PAWP and cardiac function (thermodilution or Fick method), which are both necessary to determine PVR. The mean PAP, PAWP, and PVR values obtained from RHC are used to classify PH into precapillary PH, isolated postcapillary pH, or combined pre- and postcapillary PH [78-80]. Vasoreactivity testing of the pulmonary circulation may also be performed at the time of RHC in selected patients with IPAH, heritable PAH, and drug-induced PAH to determine candidacy for calcium channel blocker treatment [79]. RHC has morbidity and mortality rates of 1.1% and 0.055%, respectively [81]. Supporting Documents The evidence table, literature search, and appendix for this topic are available at https://acsearch. acr.org/list.

Suspected Pulmonary Hypertension. More recently, 4-D flow has been used to assess the MPA and detect the hemodynamic alterations that occur with PH: decreased wall shear stress, increased tricuspid regurgitation velocity, and abnormal vortex blood flow pattern within the MPA that is associated with early-onset systolic retrograde flow [65,72-74]. MRA Chest Pulmonary MR angiography (MRA) shows morphologic changes of PH that are also depicted by MRI heart and CT/CTPA: PA enlargement, MPA to adjacent ascending aorta ratio >1, RV enlargement and hypertrophy, straightening of the interventricular septum, and pericardial thickening and effusion [61,65,66]. MRA has lower sensitivity for the detection of acute and chronic pulmonary embolism compared with CTPA [61]. There are no data to support the use of MRA chest alone as a first-line test for suspected PH; however, the combination of MRA Catheterization Right Heart RHC is an invasive procedure that defines cardiopulmonary hemodynamics and is performed after all noninvasive examinations have been completed to confirm the diagnosis of PH before initiating treatment per current guidelines [24]. RHC directly measures the PAP to confirm the diagnosis of PH as well as the PAWP and cardiac function (thermodilution or Fick method), which are both necessary to determine PVR. The mean PAP, PAWP, and PVR values obtained from RHC are used to classify PH into precapillary PH, isolated postcapillary pH, or combined pre- and postcapillary PH [78-80]. Vasoreactivity testing of the pulmonary circulation may also be performed at the time of RHC in selected patients with IPAH, heritable PAH, and drug-induced PAH to determine candidacy for calcium channel blocker treatment [79]. RHC has morbidity and mortality rates of 1.1% and 0.055%, respectively [81]. Supporting Documents The evidence table, literature search, and appendix for this topic are available at https://acsearch. acr.org/list.

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