Staging and Follow up of Esophageal Cancer. MRI Head There is no relevant literature to support MRI brain to evaluate patients suspected to have metastases after treatment.


Staging and Follow up of Esophageal Cancer. Staging and Follow-up of Esophageal Cancer Supporting Documents The evidence table, literature search, and appendix for this topic are available at https://acsearch.acr.org/list. The appendix includes the strength of evidence assessment and the final rating round tabulations for each recommendation.


Staging and Follow up of Esophageal Cancer. For additional information on the Appropriateness Criteria methodology and other supporting documents go to www.acr.org/ac.


Pulmonary Arteriovenous Malformation PAVM . About 70% to 90% of the patients with PAVMs have hereditary hemorrhagic telangiectasia (HHT) [2]. HHT is an autosomal dominant disorder associated with mutations in genes coding for endoglin and activin receptor-like kinase 1ALK1. The former leads to a phenotypical presentation with cerebral and PAVMs described as HHT type 1 [3]. The later presents with pulmonary hypertension and hepatic AVMs and is described as HHT type 2 [4]. Of patients with HHT, 1% to 2% have a SMAD4 mutation and a clinical phenotype associated with juvenile polyposis syndrome [5]. The clinical diagnosis of HHT is based on the Curacao criteria [6]. The prevalence of PAVM occurs in 1 in 5,000 individuals in the general population but can vary depending on the geographical distribution of HHT. In areas where HHT is more prevalent, PAVM prevalence can reach between 26 and 56 per 100,000 individuals. In general, there is a 1.5 to 2 times higher incidence of PAVMs in women compared to men but a male-predominance is noted in newborns [7]. Other causes of PAVMs are rare and include trauma, chest surgery, schistosomiasis, actinomycosis, mitral valve stenosis, Fanconi syndrome, cirrhosis with hepatopulmonary syndrome, and metastatic cancer [7].


Pulmonary Arteriovenous Malformation PAVM . Clinical manifestations of PAVMs depend on the size, number, type (complex versus simple), and flow through the malformations. Most patients are asymptomatic (25%-58%). Hypoxemia (27%-71%) at rest or exercise, especially orthodeoxia (worsening hypoxemia when upright) and platypnea (worsening dyspnea when upright), are classical presentations as 65% to 83% of PAVMs are in the lower lobes of the lungs [8]. Transient ischemic attacks and cerebral strokes (3.2%-55%), systemic infections, and abscesses including cerebral abscesses (0%-25%) and rarely massive hemoptysis and hemothorax (0%-2%) are other manifestations [1]. Pregnancy is associated with the rapid growth of PAVMs due to hormonal and hemodynamic consequences with a higher risk of complications from lack of filtration and rupture [9].


Pulmonary Arteriovenous Malformation PAVM . Treatment of PAVMs involves endovascular occlusion of the feeding artery and in rare instances surgical resection. Percutaneous transcatheter embolization is typically performed for the treatment of PAVMs. The feeding artery is occluded by an embolic device obliterating the arteriovenous shunt. Regardless of the size of the feeding artery, any PAVM detected by CT or catheter angiography should be considered for treatment due to the risk of paradoxical embolism [10,11]. Embolization is performed by deploying coils or plugs in the feeding artery as close to the


Pulmonary Arteriovenous Malformation PAVM . aUT Southwestern Medical Center, Dallas, Texas. bPanel Chair, Brigham & Women's Hospital, Boston, Massachusetts. cPanel Vice-Chair, Brigham & Women's Hospital, Boston, Massachusetts. dUniversity of Toronto, Toronto, Ontario, Canada; American College of Physicians. eKnight Cardiovascular Institute, Oregon Health & Science University, Portland, Oregon; Society of Cardiovascular Computed Tomography. fUT Southwestern Medical Center, Dallas, Texas; Commission on Nuclear Medicine and Molecular Imaging. gOchsner Hospital, Baton Rouge, Louisiana. hUniversity of California San Francisco, San Francisco, California. iUniversity of Wisconsin School of Medicine and Public Health, Madison, Wisconsin. jWilmington Health, Wilmington, North Carolina; American College of Chest Physicians. kCleveland Clinic, Cleveland, Ohio. lUCLA Medical Center, Los Angeles, California; The Society of Thoracic Surgeons. mVA Puget Sound Health Care System and University of Washington, Seattle, Washington. nThe Warren Alpert School of Medicine at Brown University, Providence, Rhode Island; Nuclear cardiology expert. oSouth Texas Radiology Group, P.A., San Antonio, Texas. pMercyhealth, Rockford, Illinois. qLahey Hospital and Medical Center, Burlington, Massachusetts. rEmory University, Atlanta, Georgia; American Society of Echocardiography. sBrigham & Women's Hospital, Boston, Massachusetts; Committee on Emergency Radiology-GSER. tSpecialty Chair, Massachusetts General Hospital, Boston, Massachusetts.


Pulmonary Arteriovenous Malformation PAVM . 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.


Pulmonary Arteriovenous Malformation PAVM . Reprint requests to: publications@acr.org


Pulmonary Arteriovenous Malformation PAVM . Pulmonary Arteriovenous Malformation (PAVM) arteriovenous communication as possible. Follow-up CT angiography (CTA) to detect persistence/new lesions within 6 to 12 months followed by every 3 to 5 years is recommended by the international guidelines for the diagnosis and management of HHT [10]. Persistent perfusion of PAVMs following embolization carries the continued risk of paradoxical embolism and is a vexing problem to re-treat with success rates up to 44% to 85% [12]. The persistence rates vary with the embolic material and are primarily due to arterial recanalization. Other causes include pulmonary to pulmonary and systemic to pulmonary perfusion of the venous sac. Persistent sac perfusion following embolization with different embolic materials vary from 5% to 21% for coils alone, 4% to 6% for nitinol vascular plugs, and 0% to 2% for microvascular plugs [13,14].


Pulmonary Arteriovenous Malformation PAVM . Use of maximum intensity projection postprocessing has shown to increase the detection rates and reduce reporting times for small PAVMs both in children and adults. Maximum intensity projection also detects the anatomy and size of the feeding artery with higher accuracy compared to thin-section conventional CT images [18-20].


Pulmonary Arteriovenous Malformation PAVM . Postembolization scans for PAVMs are prone to artifacts that interfere with the evaluation of persistent flow. Spectral and dual-energy CT have been studied in other anatomical locations in reducing the coil and other metallic artifacts [21,22]. There are no studies evaluating their role in PAVM, but these techniques may improve posttreatment image interpretation by reducing artifacts.


Pulmonary Arteriovenous Malformation PAVM . For the purposes of distinguishing between CT and CT angiography (CTA), ACR Appropriateness Criteria topics use the definition in the ACR-NASCI-SIR-SPR Practice Parameter for the Performance and Interpretation of Body Computed Tomography Angiography (CTA) [23]:


Pulmonary Arteriovenous Malformation PAVM . 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.


Pulmonary Arteriovenous Malformation PAVM . OR Discussion of Procedures by Variant Variant 1: Presenting with a transient ischemic attack, or seizures, or brain abscess, or altered sensorium. Chest radiography reveals a lung nodule. Suspected pulmonary arteriovenous malformation (PAVM). Next imaging study. Arteriography Pulmonary The real-time nature of pulmonary arteriography allows for high accuracy in delineating the angioarchitecture and detection of flow characteristics such as the early draining vein. In a study comparing the specificity of pulmonary arteriography and CTA, pulmonary arteriography was noted to have a higher specificity for detecting the angioarchitecture compared to CTA (100% versus 78%) [24]. Pulmonary angiography is performed as a part of the


Pulmonary Arteriovenous Malformation PAVM . Pulmonary Arteriovenous Malformation (PAVM)


Pulmonary Arteriovenous Malformation PAVM . treatment procedure and does not have a standalone diagnostic role in detecting PAVM. An exception where pulmonary angiogram would be helpful as an initial diagnostic imaging tool is in a patient who is hemodynamically unstable with clinical suspicion of pulmonary hemorrhage from a PAVM [25].


Pulmonary Arteriovenous Malformation PAVM . CT Chest With IV Contrast Chest CT with IV contrast offers high spatial resolution and can detect the number, size, and distribution of PAVMs accurately. Contrast-enhanced CT provides similar diagnostic accuracy as noncontrast CT due to the high natural contrast inherent to pulmonary anatomy. IV contrast material administration adds a small risk of air embolism in patients with PAVM. Adequate precaution should be taken to prevent air embolism [10,26]. Cross-sectional anatomy displayed on CT chest with IV contrast is useful in treatment planning [10,27].


Pulmonary Arteriovenous Malformation PAVM . CT Chest Without and With IV Contrast There is limited data to support obtaining a CT chest with and without IV contrast in the setting of suspected PAVM. A study by Nawaz et al [24] compared CT with and without IV contrast to digital subtraction angiography (DSA) for assessment of PAVMs. Their study showed superior sensitivity of CT compared to DSA for detection of PAVM; however, the specificity for CT was inferior to that of DSA. Cross-sectional anatomy displayed on CT chest with IV contrast is useful in treatment planning [10,27]. The benefit of using CT chest without and with IV contrast for assessing PAVM compared to stand-alone CT without IV contrast or CT with IV contrast is unclear [24].


Pulmonary Arteriovenous Malformation PAVM . CT Chest Without IV Contrast Noncontrast chest CT scan is helpful in confirming the diagnosis of PAVM. Like CT chest with IV contrast, Noncontrast CT offers high spatial resolution and can detect the number, size, and distribution of PAVMs accurately. Remy et al [28] were able to predict angioarchitecture of the PAVMs in 95% of cases using noncontrast CT and 3-D reconstruction. Cross-sectional anatomy displayed on CT chest without IV contrast is useful in treatment planning [10,27].


Pulmonary Arteriovenous Malformation PAVM . CTA Chest With IV Contrast CTA chest provides similar diagnostic accuracy as noncontrast CT due to the high natural contrast inherent to pulmonary anatomy. IV contrast material administration adds a small risk of air embolism in patients with PAVM. Adequate precaution should be taken to prevent air embolism. Unlike CTA pulmonary arteries (CTPA), the vascular enhancement during CTA is timed for the aorta and its branches and, thus, it may help identify systemic supply to PAVMs via the systemic arteries [10,29,30]. Cross-sectional anatomy displayed on CT chest with IV contrast is useful in treatment planning [10,27].


Pulmonary Arteriovenous Malformation PAVM . CTA Pulmonary Arteries With IV Contrast CTPA specifically assesses the pulmonary vasculature. IV contrast material is timed for optimum evaluation of the pulmonary arteries. Use of CTPA for evaluation of PAVM is used in clinical practice when considering a contrast- enhanced CT scan for evaluating PAVM. Like other CT techniques, CTPA offers high special resolution and can detect the number, size, and distribution of PAVMs accurately. CTPA provides similar diagnostic accuracy as noncontrast CT due to the high natural contrast inherent to pulmonary anatomy. IV contrast material administration adds a small risk of air embolism in patients with PAVM. Adequate precaution should be taken to prevent air [27]. Correlating the PAVM grade with contrast-enhanced echo has been shown to be more sensitive with CTPA compared to noncontrast CT [31]. Cross-sectional anatomy displayed on CT chest with IV contrast is useful in treatment planning [10,27].


Pulmonary Arteriovenous Malformation PAVM . MRA Chest Without and With IV Contrast There is no role for the routine use of MR angiography (MRA) chest without and with IV contrast in the workup of a patient suspected of a PAVM. Similar to chest CTA, MRA chest may identify systemic arterial supply to PAVM.


Pulmonary Arteriovenous Malformation PAVM . MRA Chest Without IV Contrast There is no role for the routine use of MRA chest without IV contrast in the workup of a patient suspected of a PAVM.


Pulmonary Arteriovenous Malformation PAVM . MRA Pulmonary Arteries Without and With IV Contrast Contrast-enhanced MRA pulmonary arteries provides anatomical information about the presence, number, size, and location of PAVMs. Schneider et al [32] evaluated 203 patients with HHT or first-degree relatives with HHT using contrast-enhanced MRA. Patients with definite and uncertain diagnosis of PAVM on MRA underwent pulmonary angiogram. Pulmonary angiogram detected only 77% to 80% of the PAVMs that were seen on MRA. In their study, the majority of the PAVMs not detected by pulmonary angiogram were <5 mm in size. The size criterion was


Pulmonary Arteriovenous Malformation PAVM . Pulmonary Arteriovenous Malformation (PAVM) defined as the size of the PAVM itself and not of the feeding artery. A more recent study by Van den Heuvel et al [33] investigated the sensitivity of contrast-enhanced MRA for detection of PAVMs with a feeding artery >2 cm in children and young adults. They enrolled 53 patients who had a TTCE grade 2 or 3 who underwent chest CT and were found to have the PAVM with a feeding artery >2 cm to receive a contrast-enhanced MRA. The sensitivity of contrast-enhanced MRA to detect PAVMs with a feeding artery size of >2cm was 92%, and the specificity ranged from 67% to 96%.


Pulmonary Arteriovenous Malformation PAVM . MRA Pulmonary Arteries Without IV Contrast There is no role for the routine use of MRA pulmonary angiography without IV contrast in the workup of a patient suspected of a PAVM.


Pulmonary Arteriovenous Malformation PAVM . Pertechnetate Albumin Pulmonary Scan There is no role for pertechnetate albumin pulmonary scan in a modern day practice. Historically, this technique was used to detect and quantify right to left shunting before and after treatment of a PAVM [34,35].


Pulmonary Arteriovenous Malformation PAVM . Radiography Chest The radiographic appearance of a lower lobe pulmonary nodule with a branching afferent artery and dilated efferent vein defines the classical appearance of PAVM on chest radiography. The sensitivity of chest radiography is 60% to 70% with a 98% specificity when the classical findings are present [36]. The afferent and efferent vasculature and smaller PAVMs may be difficult to see on a single-view chest radiograph. Best diagnostic results are obtained when a 2-view chest radiograph, posteroanterior view, and lateral view, is performed [37]. The role of chest radiography in the diagnosis of a suspected PAVM is limited due to its poor sensitivity.


Pulmonary Arteriovenous Malformation PAVM . US Echocardiography Transesophageal There is no role for ultrasound (US) transesophageal echocardiography (TEE) as a standalone diagnostic tool in the evaluation of PAVMs. The usefulness of TEE in the context of PAVM is to rule out intracardiac shunts [38]. Its ability to demonstrate the interatrial septum and the insertion of the pulmonary veins into the left atrium is useful to evaluate the anatomical variations [39].


Pulmonary Arteriovenous Malformation PAVM . US Echocardiography Transesophageal With IV Contrast TEE with IV agitated saline contrast material is not routinely used to diagnose PAVM. Contrast-enhanced TEE may be helpful to locate a PAVM based on the excellent visualization of the 4 pulmonary venous ostia as veins drain into the left atrium. Based on the visualization of contrast material emanating from a particular pulmonary vein, the location of the PAVM in that venous territory can be confirmed [38,40]. In the presence of multiple PAVMs, the usefulness of this imaging modality in identifying the location of the PAVMs is limited.


Pulmonary Arteriovenous Malformation PAVM . US Echocardiography Transthoracic Resting There is no role for transthoracic echocardiography (TTE) in the resting phase for the evaluation of PAVM. It does allow evaluation of intracardiac shunts and assessment of cardiac function [38].


Pulmonary Arteriovenous Malformation PAVM . US Echocardiography Transthoracic With IV Contrast TTCE is an essential diagnostic test for patients suspected of having a PAVM. TTCE with agitated saline has a 98% to 99% sensitivity and a 67% to 91% specificity for detecting PAVMs [41]. The microbubbles are visualized after 3 to 8 cardiac cycles in the left atrium after initial opacification of the right chambers in patients with an intrapulmonary shunt [1]. TTCE does not provide any information regarding the size and location of the PAVM. Based on the appearance of the bubbles in the left atrium a semiquantitative grading system has been developed [42,43]. The grades are defined as 0 with no opacification, grade 1 with <30 bubbles, grade 2 with moderate filling, and grade 3 with complete opacification of the left atrium. The grading system correlates well with the diagnosis of PAVM, with higher grades associated with larger shunts and cerebral complications [41,44,45]. Usefulness of the grading system to predict treatment of PAVM demonstrates that grades 2 and 3 have a positive predictive value of 0.21 (95% confidence interval [CI], 0.05-0.36) and 0.87 (95% CI, 0.79-0.99), respectively [44]. Adverse events including air embolism are rare with TTCE occurring in <1% [46].


Pulmonary Arteriovenous Malformation PAVM . Variant 2: Presenting with shortness of breath, or hemothorax, or hemoptysis. Patient has history of epistaxis and family history of hereditary hemorrhagic telangiectasia (HHT). Suspected PAVM. Initial imaging. Arteriography Pulmonary The real-time nature of pulmonary arteriography allows for high accuracy in delineating the angioarchitecture and detection of flow characteristics such as the early draining vein. In a study comparing the specificity of pulmonary arteriography and CTA, pulmonary arteriography was noted to have a higher specificity for detecting the


Pulmonary Arteriovenous Malformation PAVM . angioarchitecture compared to CTA (100% versus 78%) [24]. Pulmonary angiography is performed as a part of the treatment procedure and does not have a standalone diagnostic role in detecting PAVM. An exception in which pulmonary angiogram would be helpful as an initial diagnostic imaging tool is in a patient who is hemodynamically unstable with clinical suspicion of pulmonary hemorrhage from a PAVM [25].


Pulmonary Arteriovenous Malformation PAVM . CT Chest With IV Contrast Contrast-enhanced CT chest offers high spatial resolution and can detect the number, size, and distribution of PAVMs accurately. Contrast-enhanced CT provides similar diagnostic accuracy as noncontrast CT due to the high natural contrast inherent to pulmonary anatomy. IV contrast material administration adds a small risk of air embolism in patients with PAVM. Adequate precaution should be taken to prevent air embolism [10,26]. Cross- sectional anatomy displayed on CT chest with IV contrast is useful in treatment planning [10,27].


Pulmonary Arteriovenous Malformation PAVM . CT Chest Without and With IV Contrast There is limited data to support obtaining a CT chest with and without IV contrast in the setting of suspected PAVM. A study by Nawaz et al [24] compared CT with and without IV contrast to digital subtraction angiography (DSA) for assessment of PAVMs. Their study showed superior sensitivity of CT compared to DSA for detection of PAVM; however, the specificity for CT was inferior to that of DSA. Cross-sectional anatomy displayed on CT chest with IV contrast is useful in treatment planning [10,27]. The benefit of using CT chest without and with IV contrast for assessing PAVM compared to stand-alone CT without IV contrast or CT with IV contrast is unclear [24].


Pulmonary Arteriovenous Malformation PAVM . CT Chest Without IV Contrast Noncontrast chest CT scan is helpful in confirming the diagnosis of PAVM. Like CT chest with IV contrast, Noncontrast CT offers high spatial resolution and can detect the number, size, and distribution of PAVMs accurately. Remy et al [28] were able to predict angioarchitecture of the PAVMs in 95% of cases using noncontrast CT and 3-D reconstruction. Cross-sectional anatomy displayed on CT chest without IV contrast is useful in treatment planning [10,27].


Pulmonary Arteriovenous Malformation PAVM . CTA Chest With IV Contrast CTA chest provides similar diagnostic accuracy as noncontrast CT due to the high natural contrast inherent to pulmonary anatomy. IV contrast material administration adds a small risk of air embolism in patients with PAVM. Adequate precaution should be taken to prevent air embolism. Unlike CTPA, the vascular enhancement during CTA is timed for the aorta and its branches and, thus, it may help identify systemic supply to PAVMs via the systemic arteries [10,29,30]. Cross-sectional anatomy displayed on CT chest with IV contrast is useful in treatment planning [10,27].


Pulmonary Arteriovenous Malformation PAVM . CTA Pulmonary Arteries With IV Contrast CTPA specifically assesses the pulmonary vasculature. IV contrast material is timed for optimum evaluation of the pulmonary arteries. Use of CTPA for evaluation of PAVM is used in clinical practice when considering a contrast- enhanced CT scan for evaluating PAVM. Like other CT techniques, CTPA offers high special resolution and can detect the number, size, and distribution of PAVMs accurately. CTPA provides similar diagnostic accuracy as noncontrast CT due to the high natural contrast inherent to pulmonary anatomy. IV contrast material administration adds a small risk of air embolism in patients with PAVM. Adequate precaution should be taken to prevent air [27]. Correlating the PAVM grade with contrast-enhanced echo has been shown to be more sensitive with CTPA compared to noncontrast CT [31]. Cross-sectional anatomy displayed on CT chest with IV contrast is useful in treatment planning [10,27].


Pulmonary Arteriovenous Malformation PAVM . MRA Chest Without and With IV Contrast There is no role for the routine use of MRA chest without and with IV contrast in the workup of a patient suspected of a PAVM.


Pulmonary Arteriovenous Malformation PAVM . MRA Chest Without IV Contrast There is no role for the routine use of MRA chest without IV contrast in the workup of a patient suspected of a PAVM.


Pulmonary Arteriovenous Malformation PAVM . MRA Pulmonary Arteries Without and With IV Contrast Contrast-enhanced MRA pulmonary arteries provides anatomical information about the presence, number, size, and location of PAVMs. Schneider et al [32] evaluated 203 patients with HHT or first-degree relatives with HHT using contrast-enhanced MRA. Patients with definite and uncertain diagnosis of PAVM on MRA underwent pulmonary angiogram. Pulmonary angiogram detected only 77% to 80% of the PAVMs that were seen on MRA. In their study,


Pulmonary Arteriovenous Malformation PAVM . Pulmonary Arteriovenous Malformation (PAVM) the majority of the PAVMs not detected by pulmonary angiogram were <5 mm in size. The size criterion was defined as the size of the PAVM itself and not of the feeding artery. A more recent study by Van den Heuvel et al [33] investigated the sensitivity of contrast-enhanced MRA for detection of PAVMs with a feeding artery >2 cm in children and young adults. They enrolled 53 patients who had a TTCE grade 2 or 3 who underwent chest CT and were found to have the PAVM with a feeding artery >2 cm to receive a contrast-enhanced MRA. The sensitivity of contrast-enhanced MRA to detect PAVMs with a feeding artery size of >2cm was 92%, and the specificity ranged from 67% to 96%.


Pulmonary Arteriovenous Malformation PAVM . MRA Pulmonary Arteries Without IV Contrast There is no role for the routine use of MRA pulmonary angiography without IV contrast in the workup of a patient suspected of a PAVM.


Pulmonary Arteriovenous Malformation PAVM . Pertechnetate Albumin Pulmonary Scan There is no role for pertechnetate albumin pulmonary scan in a modern day practice. Historically, this technique was used to detect and quantify right to left shunting before and after treatment of a PAVM [34,35].


Pulmonary Arteriovenous Malformation PAVM . Radiography Chest The radiographic appearance of a lower lobe pulmonary nodule with a branching afferent artery and dilated efferent vein defines the classical appearance of PAVM on chest radiography. The sensitivity of chest radiography is 60% to 70% with a 98% specificity when the classical findings are present [36]. The afferent and efferent vasculature and smaller PAVMs may be difficult to see on a single-view chest radiograph. Best diagnostic results are obtained when a 2-view chest radiograph, posteroanterior view, and lateral view is performed [37]. The role of chest radiography in the diagnosis of a suspected PAVM is limited due to its poor sensitivity.


Pulmonary Arteriovenous Malformation PAVM . US Echocardiography Transesophageal There is no role for TEE as a standalone diagnostic tool in the evaluation of PAVMs. The usefulness of TEE in the context of PAVM is to rule out intracardiac shunts [38]. Its ability to demonstrate the interatrial septum and the insertion of the pulmonary veins into the left atrium is useful to evaluate the anatomical variations [39].


Pulmonary Arteriovenous Malformation PAVM . US Echocardiography Transesophageal With IV Contrast TEE with IV agitated saline contrast material is not routinely used to diagnose PAVM. Contrast-enhanced TEE maybe helpful to locate a PAVM based on the excellent visualization of the 4 pulmonary venous ostia as veins drain into the left atrium. Based on the visualization of contrast material emanating from a particular pulmonary vein, the location of the PAVM in that venous territory can be confirmed [38,40]. In the presence of multiple PAVMs, the usefulness of this imaging modality in identifying the location of the PAVMs is limited.


Pulmonary Arteriovenous Malformation PAVM . US Echocardiography Transthoracic Resting There is no role for TTE in the resting phase for evaluation of PAVM. It does allow evaluation of intracardiac shunts and assessment of cardiac function [38].


Pulmonary Arteriovenous Malformation PAVM . US Echocardiography Transthoracic With IV Contrast TTCE is an essential diagnostic test for patients suspected of having a PAVM. TTCE with agitated saline has a 98% to 99% sensitivity and a 67% to 91% specificity for detecting PAVMs [41]. The microbubbles are visualized after 3 to 8 cardiac cycles in the left atrium after initial opacification of the right chambers in patients with an intrapulmonary shunt [1]. TTCE does not provide any information regarding the size and location of the PAVM. Based on the appearance of the bubbles in the left atrium a semiquantitative grading system has been developed [42,43]. The grades are defined as 0, with no opacification, grade 1 with <30 bubbles, grade 2 with moderate filling, and grade 3 with complete opacification of the left atrium. The grading system correlates well with the diagnosis of PAVM, with higher grades associated with larger shunts and cerebral complications [41,44,45]. Usefulness of the grading system to predict treatment of PAVM demonstrates that grades 2 and 3 have a positive predictive value of 0.21 (95% CI, 0.05-0.36) and 0.87 (95% CI, 0.79-0.99), respectively [44]. Adverse events including air embolism are rare with TTCE occurring in <1% [46].


Pulmonary Arteriovenous Malformation PAVM . Variant 3: Asymptomatic with a family history of HHT and suspected PAVM. Initial imaging. Arteriography Pulmonary The real-time nature of pulmonary arteriography allows for high accuracy in delineating the angioarchitecture and detection of flow characteristics such as the early draining vein. In a study comparing the specificity of pulmonary arteriography and CTA, pulmonary arteriography was noted to have a higher specificity for detecting the


Pulmonary Arteriovenous Malformation PAVM . Pulmonary Arteriovenous Malformation (PAVM) angioarchitecture compared to CTA (100% versus 78%) [24]. Pulmonary angiography is performed as a part of the treatment procedure and does not have a standalone diagnostic role in detecting PAVM.


Pulmonary Arteriovenous Malformation PAVM . CT Chest With IV Contrast Contrast-enhanced CT chest offers high spatial resolution and can detect the number, size, and distribution of PAVMs accurately. Contrast-enhanced CT provides similar diagnostic accuracy as noncontrast CT due to the high natural contrast inherent to pulmonary anatomy. IV contrast material administration adds a small risk of air embolism in patients with PAVM. Adequate precaution should be taken to prevent air embolism [10,26]. Cross- sectional anatomy displayed on CT chest with IV contrast is useful in treatment planning [10,27].


Pulmonary Arteriovenous Malformation PAVM . CT Chest Without and With IV Contrast There is limited data to support obtaining a CT chest with and without IV contrast in the setting of suspected PAVM. A study by Nawaz et al [24] compared CT with and without IV contrast to DSA for assessment of PAVMs. Their study showed superior sensitivity of CT compared to DSA for detection of PAVM; however, the specificity for CT was inferior to that of DSA. Cross-sectional anatomy displayed on CT chest with IV contrast is useful in treatment planning [10,27]. The benefit of using CT chest without and with IV contrast for assessing PAVM compared to stand-alone CT without IV contrast or CT with IV contrast is unclear [24].


Pulmonary Arteriovenous Malformation PAVM . CT Chest Without IV Contrast Noncontrast chest CT scan is helpful in confirming the diagnosis of PAVM. Like CT chest with IV contrast, noncontrast CT offers high spatial resolution and can detect the number, size, and distribution of PAVMs accurately. Remy et al [28] were able to predict angioarchitecture of the PAVMs in 95% of cases using noncontrast CT and 3- D reconstruction. Cross-sectional anatomy displayed on CT chest without IV contrast is useful in treatment planning [10,27].


Pulmonary Arteriovenous Malformation PAVM . CTA Chest With IV Contrast CTA chest provides similar diagnostic accuracy as noncontrast CT due to the high natural contrast inherent to pulmonary anatomy. IV contrast material administration adds a small risk of air embolism in patients with PAVM. Adequate precaution should be taken to prevent air embolism. Unlike CTPA, the vascular enhancement during CTA is timed for the aorta and its branches and, thus, it may help identify systemic supply to PAVMs via the systemic arteries [10,29,30]. Cross-sectional anatomy displayed on CT chest with IV contrast is useful in treatment planning [10,27].


Pulmonary Arteriovenous Malformation PAVM . CTA Pulmonary Arteries With IV Contrast CTPA specifically assesses the pulmonary vasculature. IV contrast material is timed for optimum evaluation of the pulmonary arteries. Use of CTPA for evaluation of PAVM is used in clinical practice when considering a contrast- enhanced CT scan for evaluating PAVM. Like other CT techniques, CTPA offers high special resolution and can detect the number, size, and distribution of PAVMs accurately. CTPA provides similar diagnostic accuracy as noncontrast CT due to the high natural contrast inherent to pulmonary anatomy. IV contrast material administration adds a small risk of air embolism in patients with PAVM. Adequate precaution should be taken to prevent air [27]. Correlating the PAVM grade with contrast-enhanced echo has been shown to be more sensitive with CTPA compared to noncontrast CT [31]. Cross-sectional anatomy displayed on CT chest with IV contrast is useful in treatment planning [10,27].


Pulmonary Arteriovenous Malformation PAVM . MRA Chest Without and With IV Contrast There is no role for the routine use of MRA chest without and with IV contrast in the workup of a patient suspected of a PAVM.


Pulmonary Arteriovenous Malformation PAVM . MRA Chest Without IV Contrast There is no role for the routine use of MRA chest without IV contrast in the workup of a patient suspected of a PAVM.


Pulmonary Arteriovenous Malformation PAVM . MRA Pulmonary Arteries Without and With IV Contrast Contrast-enhanced MRA pulmonary arteries provides anatomical information about the presence, number, size, and location of PAVMs. Schneider et al [32] evaluated 203 patients with HHT or first-degree relatives with HHT using contrast-enhanced MRA. Patients with definite and uncertain diagnosis of PAVM on MRA underwent pulmonary angiogram. Pulmonary angiogram detected only 77% to 80% of the PAVMs that were seen on MRA. In their study, the majority of the PAVMs not detected by pulmonary angiogram were <5 mm in size. The size criterion was defined as the size of the PAVM itself and not of the feeding artery. A more recent study by Van den Heuvel et al


Pulmonary Arteriovenous Malformation PAVM . Pulmonary Arteriovenous Malformation (PAVM) [33] investigated the sensitivity of contrast-enhanced MRA for detection of PAVMs with a feeding artery >2 cm in children and young adults. They enrolled 53 patients who had a TTCE grade 2 or 3 who underwent chest CT and were found to have the PAVM with a feeding artery >2 cm to receive a contrast-enhanced MRA. The sensitivity of contrast-enhanced MRA to detect PAVMs with a feeding artery size of >2cm was 92%, and the specificity ranged from 67% to 96%.


Pulmonary Arteriovenous Malformation PAVM . MRA Pulmonary Arteries Without IV Contrast There is no role for the routine use of MRA pulmonary angiography without IV contrast in the workup of a patient suspected of a PAVM.


Pulmonary Arteriovenous Malformation PAVM . Pertechnetate Albumin Pulmonary Scan There is no role for pertechnetate albumin pulmonary scan in a modern day practice. Historically, this technique was used to detect and quantify right to left shunting before and after treatment of a PAVM [34,35].


Pulmonary Arteriovenous Malformation PAVM . Radiography Chest The radiographic appearance of a lower lobe pulmonary nodule with a branching afferent artery and dilated efferent vein defines the classical appearance of PAVM on chest radiography. The sensitivity of chest radiography is 60% to 70% with a 98% specificity when the classical findings are present [36]. The afferent and efferent vasculature and smaller PAVMs may be difficult to see on a single-view chest radiograph. Best diagnostic results are obtained when a 2-view chest radiograph, posteroanterior view, and lateral view is performed [37].


Pulmonary Arteriovenous Malformation PAVM . US Echocardiography Transesophageal There is no role for TEE as a standalone diagnostic tool in the evaluation of PAVMs. The usefulness of TEE in the context of PAVM is to rule out intracardiac shunts [38]. Its ability to demonstrate the interatrial septum and the insertion of the pulmonary veins into the left atrium is useful to evaluate the anatomical variations [39].


Pulmonary Arteriovenous Malformation PAVM . US Echocardiography Transesophageal With IV Contrast TEE with IV agitated saline contrast material is not routinely used to diagnose PAVM. Contrast-enhanced TEE may be helpful to locate a PAVM based on the excellent visualization of the 4 pulmonary venous ostia as veins drain into the left atrium. Based on the visualization of contrast material emanating from a particular pulmonary vein, the location of the PAVM in that venous territory can be confirmed [38,40]. In the presence of multiple PAVMs, the usefulness of this imaging modality in identifying the location of the PAVMs is limited.


Pulmonary Arteriovenous Malformation PAVM . US Echocardiography Transthoracic Resting There is no role for TTE in the resting phase for the evaluation of PAVM. It does allow evaluation of intracardiac shunts and assessment of cardiac function [38].


Pulmonary Arteriovenous Malformation PAVM . US Echocardiography Transthoracic With IV Contrast TTCE is an essential diagnostic test for patients suspected of having a PAVM. TTCE with agitated saline has a 98% to 99% sensitivity and a 67% to 91% specificity for detecting PAVMs [41]. The microbubbles are visualized after 3 to 8 cardiac cycles in the left atrium after initial opacification of the right chambers in patients with an intrapulmonary shunt [1]. TTCE does not provide any information regarding the size and location of the PAVM. Based on the appearance of the bubbles in the left atrium a semiquantitative grading system has been developed [42,43]. The grades are defined as 0 with no opacification, grade 1 with <30 bubbles, grade 2 with moderate filling, and grade 3 with complete opacification of the left atrium. The grading system correlates well with the diagnosis of PAVM, with higher grades associated with larger shunts and cerebral complications [41,44,45]. Usefulness of the grading system to predict treatment of PAVM demonstrates that grades 2 and 3 have a positive predictive value of 0.21 (95% CI, 0.05-0.36) and 0.87 (95% CI, 0.79-0.99), respectively [44]. Adverse events including air embolism are rare with TTCE occurring in <1% [46].


Pulmonary Arteriovenous Malformation PAVM . Variant 4: Presenting to establish care with a past history of a treated PAVM. Follow-up (surveillance) imaging following embolization of PAVM. Arteriography Pulmonary The real-time nature of pulmonary arteriography allows for high accuracy for delineating the angioarchitecture and detection of flow characteristics such as the early draining vein. Pulmonary angiogram is the reference standard to detect reperfusion of a treated AVM, but the angiogram is performed as a part of the treatment protocol and not done as a diagnostic test [10]. In patients who have inconclusive findings on CT, pulmonary angiography can assess recanalized PAVMs.


Pulmonary Arteriovenous Malformation PAVM . Pulmonary Arteriovenous Malformation (PAVM) CT Chest With IV Contrast The high natural contrast inherent to pulmonary anatomy on noncontrast CT and the small risk of air embolism while administering IV medications renders CT chest with IV contrast unnecessary in the diagnosis of PAVM [10]. Artifacts from the embolic material limits the usefulness of contrast enhancement as a tool to evaluate reperfusion [47]. The role of contrast-enhanced CT has been studied after embolotherapy for PAVM in the context of detecting systemic collaterals by Brillet et al [29] in 32 patients. They found systemic collaterals in 13 patients that would otherwise have been missed on noncontrast CT. The role of contrast-enhanced CT scan after PAVM embolization is unclear. Cross-sectional anatomy displayed on CT chest with IV contrast is useful in further treatment planning if new or recanalized PAVMs are detected [10,27].


Pulmonary Arteriovenous Malformation PAVM . CT Chest Without and With IV Contrast The high natural contrast inherent to pulmonary anatomy on noncontrast CT and the small risk of air embolism while administering IV medications renders CT chest with IV contrast unnecessary in the diagnosis of PAVM [10]. Artifacts from the embolic material limits the usefulness of contrast enhancement as a tool to evaluate reperfusion [47]. The role of contrast-enhanced CT has been studied after embolotherapy for PAVM in the context of detecting systemic collaterals by Brillet et al [29] in 32 patients. They found systemic collaterals in 13 patients that would otherwise have been missed on noncontrast CT. The role of contrast-enhanced CT scan after PAVM embolization is unclear. Cross-sectional anatomy displayed on CT chest with IV contrast is useful in further treatment planning if new or recanalized PAVMs are detected [10,27].


Pulmonary Arteriovenous Malformation PAVM . CTA Chest With IV Contrast CTA also provides similar diagnostic accuracy as noncontrast CT due to the high natural contrast inherent to pulmonary anatomy. Contrast administration adds a small risk of air embolism in patients with PAVM. Adequate precaution should be taken to prevent air embolism. CTA may help identify systemic supply to large PAVMs via the systemic arteries [10,29,30]. Artifacts from the embolic material limit the usefulness of contrast enhancement as a tool to evaluate the reperfusion [47]. The role of contrast-enhanced CT has been studied after embolotherapy for PAVM in the context of detecting systemic collaterals by Brillet et al [29] in 32 patients. They found systemic collaterals in 13 patients that would otherwise have been missed on noncontrast CT. Another study by Remy-Jardin et at [30] showed that long-term CTA follow-up of initially successfully treated PAVMs revealed successful embolotherapy of 75% and partially or completely failed embolotherapy of 25% of PAVMs. Cross-sectional anatomy displayed on CT chest with IV contrast is useful in further treatment planning if new or recanalized PAVMs are detected [10,27].


Pulmonary Arteriovenous Malformation PAVM . CTA Pulmonary Arteries With IV Contrast CTPA specifically assesses the pulmonary vasculature. IV contrast is timed for optimum evaluation of the pulmonary arteries. Although, there is limited literature specific to CTA of pulmonary arteries for evaluation of PAVM. This protocol is used in clinical practice when considering contrast-enhanced CT scan for evaluating PAVM. Like other CT techniques, CTPA offers high special resolution and can detect the number, size, and distribution of PAVMs accurately. CTPA provides similar diagnostic accuracy as noncontrast CT due to the high natural contrast inherent to pulmonary anatomy. IV contrast material administration adds a small risk of air embolism in patients with PAVM. Adequate precaution should be taken to prevent air [27]. Correlating the PAVM grade with contrast-enhanced echo has been shown to be more sensitive with CTPA compared to noncontrast CT [31].


Pulmonary Arteriovenous Malformation PAVM . Strategies to mitigate the artifacts from embolic material by adjusting scan parameters and using dual-energy and spectral CT acquisition have shown promise in other anatomical locations. For instance, Zheng et al [54] showed


Pulmonary Arteriovenous Malformation PAVM . Pulmonary Arteriovenous Malformation (PAVM)


Pulmonary Arteriovenous Malformation PAVM . that spectral CT using metal artifact reduction software improved vascular evaluation of adjacent metallic coils in the brain. Visualization of recanalized flow remains a challenge in posttreatment CT evaluation for reperfusion.


Pulmonary Arteriovenous Malformation PAVM . MRA Chest Without and With IV Contrast There is no role for the routine use of MRA chest without and with IV contrast in the workup of a patient with treated PAVM.


Pulmonary Arteriovenous Malformation PAVM . MRA Chest Without IV Contrast There is no role for the routine use of MRA chest without IV contrast in the workup of a patient with treated PAVM.


Pulmonary Arteriovenous Malformation PAVM . MRA Pulmonary Arteries Without and With IV Contrast Dynamic MRA using time-resolved sequences has the advantage over CT, and it is not affected by the artifact from the embolic material. Time-resolved MRA can detect flow in the pulmonary vein similar to pulmonary arteriography. Shimohira et al [55] compared the sensitivity and specificity of CT and time-resolved MRA with digital subtraction angiography as a reference standard in a multi-institutional retrospective cohort of 205 patients. Using 55% as the threshold reduction of the sac diameter on CT, they found a sensitivity and specificity for CT at 82% and 81%, respectively. Time-resolved MRA on the other hand has a sensitivity and specificity of 89% and 95%, respectively. Similar findings have been reported in 28 PAVMs in 10 patients by Kawai et al [56]. In a recent study, Hong et al [57] studied the feasibility of time-resolved MRA in evaluating the feeding arteries and reperfusion after embolization of PAVMs in 9 patients with 62 PAVMs. They found a sensitivity and specificity of 100% for detection of reperfusion compared to catheter angiography as the reference standard. The visibility of the feeding arteries was compared to CT, and they found good correlation between 0.76 and 0.79 with 2 readers when using 3- D maximum intensity projection images. Time-resolved MRA also has the advantage of detecting reperfusion after repeat embolization for persistence as the burden of coiling will be greater leading to more metallic artifacts on CT [58].


Pulmonary Arteriovenous Malformation PAVM . MRA Pulmonary Arteries Without IV Contrast There is no role for the routine use of MRA pulmonary angiography without IV contrast in the workup of a patient with treated PAVM.


Pulmonary Arteriovenous Malformation PAVM . Radiography Chest The radiographic appearance of a lower lobe pulmonary nodule with a branching afferent artery and dilated efferent vein defines the classical appearance of PAVM on chest radiography. The sensitivity of chest radiography is 60% to 70% with a 98% specificity when the classical findings are present [36]. The afferent and efferent vasculature and smaller PAVMs may be difficult to see on a single-view chest radiograph. Best diagnostic results are obtained when a 2-view chest radiograph, posteroanterior view, and lateral view is performed [37]. Chest radiography has limited usefulness to detect recurrent disease in the setting of prior treated PAVM.


Pulmonary Arteriovenous Malformation PAVM . US Echocardiography Transesophageal There is no role for TEE as a standalone diagnostic tool in the evaluation of PAVMs. The usefulness of TEE in the context of PAVM is to rule out intracardiac shunts [38]. Its ability to demonstrate the interatrial septum and the insertion of the pulmonary veins into the left atrium is useful to evaluate the anatomical variations [39].


Pulmonary Arteriovenous Malformation PAVM . US Echocardiography Transesophageal With IV Contrast TEE with IV agitated saline contrast material is not routinely used to diagnose PAVM. Contrast-enhanced TEE maybe helpful to locate a PAVM based on the excellent visualization of the 4 pulmonary venous ostia as veins drain into the left atrium. Based on the visualization of contrast material emanating from a particular pulmonary vein, the location of the PAVM in that venous territory can be confirmed [38,40]. In the presence of multiple PAVMs, the usefulness of this imaging modality in identifying the location of the PAVMs may be limited.


Pulmonary Arteriovenous Malformation PAVM . US Echocardiography Transthoracic Resting There is no role for TTE in the resting phase for evaluation of PAVM. It does allow evaluation of intracardiac shunts and assessment of cardiac function [38].


Pulmonary Arteriovenous Malformation PAVM . US Echocardiography Transthoracic With IV Contrast TTCE is an essential diagnostic test for patients suspected of having a PAVM. TTCE with agitated saline has a 98% to 99% sensitivity and a 67% to 91% specificity for detecting PAVMs [41]. The microbubbles are visualized after 3 to 8 cardiac cycles in the left atrium after initial opacification of the right chambers in patients with an intrapulmonary shunt [1]. TTCE does not provide any information regarding the size and location of the PAVM. Based on the appearance of the bubbles in the left atrium a semiquantitative grading system has been developed


Pulmonary Arteriovenous Malformation PAVM . [42,43]. The grades are defined as 0 with no opacification, grade 1 with <30 bubbles, grade 2 with moderate filling, and grade 3 with complete opacification of the left atrium. The grading system correlates well with the diagnosis of PAVM, with higher grades associated with larger shunts and cerebral complications [41,44,45]. Usefulness of the grading system to predict treatment of PAVM demonstrates that grades 2 and 3 have a positive predictive value of 0.21 (95% CI, 0.05-0.36) and 0.87 (95% CI, 0.79-0.99), respectively [44]. Adverse events including air embolism are rare with TTCE occurring in <1% [46]. However, as a tool to measure the effectiveness of prior treatment, TTCE has low specificity and sensitivity.


Pulmonary Arteriovenous Malformation PAVM . Variant 5: Asymptomatic with abnormal imaging on CT or chest radiography suggestive of PAVM. Next imaging study. Arteriography Pulmonary The real-time nature of pulmonary arteriography allows for high accuracy in delineating the angioarchitecture and detection of flow characteristics such as the early draining vein. In a study comparing the specificity of pulmonary arteriography and CTA, pulmonary arteriography was noted to have a higher specificity for detecting the angioarchitecture compared to CTA (100% versus 78%) [24]. Pulmonary angiography is performed as a part of the treatment procedure and does not have a standalone diagnostic role in detecting PAVM. An exception where pulmonary angiogram would be helpful as an initial diagnostic imaging tool is in a patient who is hemodynamically unstable with clinical suspicion of pulmonary hemorrhage from a PAVM [25].


Pulmonary Arteriovenous Malformation PAVM . CT Chest With IV Contrast Contrast-enhanced CT chest offers high spatial resolution and can detect the number, size, and distribution of PAVMs accurately. Contrast-enhanced CT provides similar diagnostic accuracy as noncontrast CT due to the high natural contrast inherent to pulmonary anatomy. IV contrast material administration adds a small risk of air embolism in patients with PAVM. Adequate precaution should be taken to prevent air embolism [10,26]. Cross- sectional anatomy displayed on CT chest with IV contrast is useful in treatment planning [10,27].


Pulmonary Arteriovenous Malformation PAVM . CT Chest Without and With IV Contrast There is limited data to support obtaining a CT chest with and without IV contrast in the setting of suspected PAVM. A study by Nawaz et al [24] compared CT with and without IV contrast to DSA for assessment of PAVMs. Their study showed superior sensitivity of CT compared to DSA for detection of PAVM; however, the specificity for CT was inferior to that of DSA. Cross-sectional anatomy displayed on CT chest with IV contrast is useful in treatment planning [10,27]. The benefit of using CT chest without and with IV contrast for assessing PAVM compared to stand-alone CT without IV contrast or CT with IV contrast is unclear [24].


Pulmonary Arteriovenous Malformation PAVM . CT Chest Without IV Contrast Noncontrast chest CT scan is helpful in confirming the diagnosis of PAVM. Like CT chest with IV contrast, Noncontrast CT offers high spatial resolution and can detect the number, size, and distribution of PAVMs accurately. Remy et al [28] were able to predict angioarchitecture of the PAVMs in 95% of cases using noncontrast CT and 3-D reconstruction. Cross-sectional anatomy displayed on CT chest without IV contrast is useful in treatment planning [10,27].


Pulmonary Arteriovenous Malformation PAVM . CTA Chest With IV Contrast CTA chest also provides similar diagnostic accuracy as noncontrast CT due to the high natural contrast inherent to pulmonary anatomy. IV contrast material administration adds a small risk of air embolism in patients with PAVM. Adequate precaution should be taken to prevent air embolism. Unlike CTPA, the vascular enhancement during CTA is timed for the aorta and its branches, and, thus, it may help identify systemic supply to PAVMs via the systemic arteries [10,29,30]. Cross-sectional anatomy displayed on CT chest with IV contrast is useful in treatment planning [10,27].


Pulmonary Arteriovenous Malformation PAVM . CTA Pulmonary Arteries With IV Contrast CTPA specifically assesses the pulmonary vasculature. IV contrast material is timed for optimum evaluation of the pulmonary arteries. Use of CTPA for evaluation of PAVM is used in clinical practice when considering a contrast- enhanced CT scan for evaluating PAVM. Like other CT techniques, CTPA offers high special resolution and can detect the number, size, and distribution of PAVMs accurately. CTPA provides similar diagnostic accuracy as noncontrast CT due to the high natural contrast inherent to pulmonary anatomy. IV contrast material administration adds a small risk of air embolism in patients with PAVM. Adequate precaution should be taken to prevent air [27]. Correlating the PAVM grade with contrast-enhanced echo has been shown to be more sensitive with CTPA


Pulmonary Arteriovenous Malformation PAVM . Pulmonary Arteriovenous Malformation (PAVM) compared to noncontrast CT [31]. Cross-sectional anatomy displayed on CT chest with IV contrast is useful in treatment planning [10,27].


Pulmonary Arteriovenous Malformation PAVM . MRA Chest Without and With IV Contrast There is no role for the routine use of MRA chest without and with IV contrast in the workup of a patient suspected of a PAVM.


Pulmonary Arteriovenous Malformation PAVM . MRA Chest Without IV Contrast There is no role for the routine use of MRA chest without IV contrast in the workup of a patient suspected of a PAVM.


Pulmonary Arteriovenous Malformation PAVM . MRA Pulmonary Arteries Without and With IV Contrast Contrast-enhanced MRA pulmonary arteries provides anatomical information about the presence, number, size, and location of PAVMs. Schneider et al [32] evaluated 203 patients with HHT or first-degree relatives with HHT using contrast-enhanced MRA. Patients with definite and uncertain diagnosis of PAVM on MRA underwent pulmonary angiogram. Pulmonary angiogram detected only 77% to 80% of the PAVMs that were seen on MRA. In their study, the majority of the PAVMs not detected by pulmonary angiogram were <5 mm in size. The size criterion was defined as the size of the PAVM itself and not of the feeding artery. A more recent study by Van den Heuvel et al [33] investigated the sensitivity of contrast-enhanced MRA for detection of PAVMs with a feeding artery >2 cm in children and young adults. They enrolled 53 patients who had a TTCE grade 2 or 3 who underwent chest CT and were found to have the PAVM with a feeding artery >2 cm to receive a contrast-enhanced MRA. The sensitivity of contrast-enhanced MRA to detect PAVMs with a feeding artery size of >2cm was 92%, and the specificity ranged from 67% to 96%.


Pulmonary Arteriovenous Malformation PAVM . MRA Pulmonary Arteries Without IV Contrast There is no role for the routine use of MRA pulmonary angiography without IV contrast in the workup of a patient suspected of a PAVM.


Pulmonary Arteriovenous Malformation PAVM . US Echocardiography Transthoracic Resting There is no role for TTE in the resting phase for the evaluation of PAVM. It does allow evaluation of intracardiac shunts and assessment of cardiac function [38].


Pulmonary Arteriovenous Malformation PAVM . Pulmonary Arteriovenous Malformation (PAVM)


Pulmonary Arteriovenous Malformation PAVM . Supporting Documents The evidence table, literature search, and appendix for this topic are available at https://acsearch.acr.org/list. The appendix includes the strength of evidence assessment and the final rating round tabulations for each recommendation.


Pulmonary Arteriovenous Malformation PAVM . For additional information on the Appropriateness Criteria methodology and other supporting documents go to www.acr.org/ac.


Acute Hip Pain Suspected Fracture PCAs

Acute Hip Pain Suspected Fracture PCAs. Introduction/Background Fractures of the proximal femur (commonly referred to as hip fractures) are a frequent source of morbidity and mortality in elderly osteoporotic patients [1]. Typically the result of a ground-level fall, fractures of this type result in approximately 300,000 hospitalizations per year and are nearly twice as common in women as in men [2,3]. As the United States population continues to age, the incidence of hip fractures and associated medical costs will continue to rise, predicted to reach $18 billion by 2025 [4]. Patients suffer a substantial decline in quality of life following a hip fracture [5] as well as a 1-year mortality rate of 22% for women and 33% for men [1]. Delays in diagnosis and treatment are associated with increased cost, complication rate, length of hospital stay, and short- and long-term mortality [6-13]. Therefore, rapid diagnosis and treatment of hip fractures is critical. Hip fractures cannot be reliably diagnosed or excluded on the basis of physical examination alone; therefore, imaging plays a key role in early and accurate diagnosis [14].


Acute Hip Pain Suspected Fracture PCAs

Acute Hip Pain Suspected Fracture PCAs. Treatment for both intra- and extracapsular proximal femoral fractures in the elderly is typically surgical fixation because of the risk of further fracture displacement and the dangers of prolonged immobilization in the elderly [15]. Joint replacement may be performed for displaced fractures of the femoral neck where the risk of femoral head avascular necrosis is high. Fractures from high-force trauma are also commonly treated with surgical fixation for stability to reduce the risk of post-traumatic osteoarthritis.


Acute Hip Pain Suspected Fracture PCAs

Acute Hip Pain Suspected Fracture PCAs. Reprint requests to: publications@acr.org


Acute Hip Pain Suspected Fracture PCAs

Acute Hip Pain-Suspected Fracture

Acute Hip Pain Suspected Fracture PCAs. Acute Hip Pain-Suspected Fracture


Acute Hip Pain Suspected Fracture PCAs

Acute Hip Pain Suspected Fracture PCAs. Multiple studies have demonstrated that radiographs have limited sensitivity for fracture detection of the proximal femur, particularly in elderly osteoporotic patients [20-24]. All of these studies constitute retrospective series in which patients with negative radiographs but high clinical suspicion went on to receive a MRI scan at the discretion of the evaluating clinician. In one such study, 14% of patients with negative radiographs were found to have fractures of the hip or pelvis [23]. In this same study, Kirby et al [23] also reported 12% of patients with suspicious radiographs were found to have no fracture on MRI, illustrating limitations in the specificity of radiographs as well. Other studies have had more dramatic results, with Sankey et al [25] reporting 83 of 98 patients to have fractures after negative radiographs, 23 of whom required operative management. The variability is likely due to differing proportions of patients going on to MRI following negative radiographs in these retrospective studies. However, there is no accepted clinical decision rule to guide when patients with suspected hip fracture should have advanced imaging after negative radiographs. A new inability to bear weight is a clinically suspicious finding, although the sensitivity and specificity of this is unknown [20]. Allowing for variation between studies, the estimated prevalence of occult fracture after negative radiographs has been estimated at 4% to 10%, indicating the inability of negative radiographs alone to exclude fracture [21,26]. Risk factors for radiographically occult fracture in these studies included those age >65, low-force trauma, such as a ground-level fall, and female gender. These studies have almost exclusively included elderly patients. There is no relevant literature regarding the sensitivity and specificity of radiographs in the younger patient population, and clinicians are suggested to proceed with caution.


Acute Hip Pain Suspected Fracture PCAs

Acute Hip Pain Suspected Fracture PCAs. Radiography Pelvis There is no specific literature regarding the use of an AP view of the pelvis alone for acute hip pain following low-force trauma. Previous literature regarding the accuracy of radiography has almost exclusively evaluated AP and cross-table lateral radiographs of the hip or the combined use of AP pelvis and hip radiographs. However, it is well established that patients with clinically suspected proximal femur fracture often have fractures of the pelvis, including the sacrum and pubic rami [21,27-30]. Therefore, it has been recommended that the radiographic series include the AP view of the pelvis along with the orthogonal views of the symptomatic hip [31]. The inclusion of a pelvis radiograph also allows for comparison of potential abnormalities to the contralateral asymptomatic side. Pelvis radiographs share the same limitations in sensitivity and specificity for fracture detection as hip radiographs, and a negative radiograph alone cannot exclude fracture.


Acute Hip Pain Suspected Fracture PCAs

Acute Hip Pain Suspected Fracture PCAs. Radiography Pelvis and Hip As previously discussed, patients with clinically suspected proximal femur fracture often have fractures of the pelvis that include the sacrum and pubic rami [21,27-30]. Moreover, these pelvic fractures may occur in isolation or concomitant with a fracture of the proximal femur [28]. Therefore, it has been recommended that the radiographic series include both the AP view of the pelvis along with orthogonal views of the symptomatic hip [31]. The inclusion of a pelvis radiograph also allows for comparison of potential abnormalities to the contralateral asymptomatic side. For these reasons, an AP view of the pelvis with a cross-table lateral view of the symptomatic hip is the standard approach at many institutions, whereas some will include three views: an AP view of the pelvis, a separate AP view of the symptomatic hip, and the cross-table lateral view. There is no specific literature to compare these two approaches. Although they remain the mainstay for initial imaging, pelvis and hip radiographs share the same limitations in sensitivity and specificity for fracture detection, and negative radiographs alone cannot exclude fracture.


Acute Hip Pain Suspected Fracture PCAs

Acute Hip Pain Suspected Fracture PCAs. MRI Pelvis and Affected Hip At least 90% of proximal femoral fractures will be identified on radiographs [21]. Therefore, MRI without intravenous (IV) contrast is reserved for second-line imaging in instances of negative radiographs with continued clinical suspicion for fracture rather than as a first-line modality.


Acute Hip Pain Suspected Fracture PCAs

Acute Hip Pain Suspected Fracture PCAs. Acute Hip Pain-Suspected Fracture The use of contrast-enhanced MRI has been explored as a technique to assess femoral head perfusion in cases of proximal femoral fracture [32,33], but this modality does not play a role in initial imaging assessment.


Acute Hip Pain Suspected Fracture PCAs

Acute Hip Pain Suspected Fracture PCAs. CT Pelvis and Hips Although not as sensitive as MRI, noncontrast CT is also reserved as a problem-solving modality following radiography either to evaluate for radiographically occult fracture or to better depict fracture morphology for treatment planning purposes [34,35].


Acute Hip Pain Suspected Fracture PCAs

Acute Hip Pain Suspected Fracture PCAs. There is no relevant literature to support the use of contrast-enhanced CT as an initial imaging modality in instances of acute hip pain following low-force trauma.


Acute Hip Pain Suspected Fracture PCAs

Acute Hip Pain Suspected Fracture PCAs. There is no relevant literature to support the use of multiphase CT as an initial imaging modality in instances of acute hip pain following low-force trauma.


Acute Hip Pain Suspected Fracture PCAs

Acute Hip Pain Suspected Fracture PCAs. US Hip Although there has been limited investigation into the use of ultrasound (US) for hip fracture detection, US does not play a role as the initial imaging in this setting [36].


Acute Hip Pain Suspected Fracture PCAs

Acute Hip Pain Suspected Fracture PCAs. Bone Scan Hips There is no relevant literature to support the use of a nuclear medicine bone scan as an initial imaging modality in instances of acute hip pain following low-force trauma.


Acute Hip Pain Suspected Fracture PCAs

Acute Hip Pain Suspected Fracture PCAs. Variant 2: Acute hip pain. Fall or minor trauma. Negative radiographs. Suspect fracture. Next imaging study. MRI Pelvis and Affected Hip There is considerable literature regarding the use of noncontrast MRI for the detection of radiographically occult proximal femoral fractures. An early study by Quinn et al [37] found MRI to be 100% accurate for fracture detection in patients with indeterminate radiographs using clinical outcomes as the gold standard. A subsequent study by Pandey et al [38] found no missed fractures in 10 of 33 patients with negative MRIs, all of whom were followed clinically for at least 6 months. A 2008 study showed 99% sensitivity of MRI, both for proximal femoral fractures and fractures of the pelvis [39]. With multiple studies indicating near 100% sensitivity for proximal femoral fracture, it has been suggested that a negative MRI may allow for confident discharge from the emergency department and reduce the number of cautionary admissions [23,29]. Conversely, rapid diagnosis of surgical fractures reduces delay to treatment with associated improved outcomes [10].


Acute Hip Pain Suspected Fracture PCAs

Acute Hip Pain Suspected Fracture PCAs. Several additional studies have also shown high diagnostic accuracy for diagnosis of both pelvis fractures and soft-tissue injuries in addition to fractures of the proximal femur [28,30,39]. This versatility is important as many series have shown a high incidence of extrafemoral trauma in patients with acute hip pain and negative radiographs. For example, in the study by Ohishi et al [30], of 113 patients, 38% had fractures of the proximal femur and 33% had fractures of the pelvis. In another retrospective series, Dominguez et al [21] found pelvic fractures to be more common than proximal femur fractures in this patient population, emphasizing the importance of accuracy in the assessment of extrafemoral trauma. Although many of these pelvic fractures and soft-tissue injuries may not be treated surgically, correct diagnosis allows for appropriate conservative treatment, including protected weight-bearing, pain control, deep vein thrombosis prophylaxis, and skilled rehabilitation.


Acute Hip Pain Suspected Fracture PCAs

Acute Hip Pain Suspected Fracture PCAs. In addition to its increased sensitivity for fracture detection, MRI has been shown to be useful in characterizing fracture morphology. Seemingly isolated fractures of the greater trochanter diagnosed on radiography frequently have intertrochanteric extension when evaluated with MRI [22]. In a classic study of 30 patients, Schultz et al [40] demonstrated the use of MRI to accurately depict the extent of the fracture line in these radiographically occult intertrochanteric fractures. There is an increasing trend to treat incomplete intertrochanteric fractures conservatively. For example, in a small series of 8 patients, Alam et al [41] found that of the 5 patients treated conservatively, none went on to complete their fracture. Several authors have suggested that with its ability to depict fracture morphology with accuracy, MRI may have a continued role to play in directing treatment [22,40].


Acute Hip Pain Suspected Fracture PCAs

Acute Hip Pain Suspected Fracture PCAs. Specific scanning protocols have emphasized either speed or comprehensiveness. A 2003 study of 93 cases found 100% sensitivity for the coronal short tau inversion-recovery (STIR) sequence alone [42], and a more recent study found 99% sensitivity of the coronal STIR sequence with increasing confidence and specificity with the addition of a coronal T1 sequence [43]. Given the increasing throughput pressures in the emergency department and the


Acute Hip Pain Suspected Fracture PCAs

Acute Hip Pain Suspected Fracture PCAs. Acute Hip Pain-Suspected Fracture difficulty of older patients in tolerating long scan times, there continues to be interest in developing rapid and accurate MRI protocols.


Acute Hip Pain Suspected Fracture PCAs

Acute Hip Pain Suspected Fracture PCAs. With the diagnostic accuracy of noncontrast MRI approaching 100%, there has been little need to explore the addition of IV gadolinium contrast solely for the purposes of fracture detection. Rather, the interest has been in the use of dynamic MRI to evaluate femoral head perfusion for prognostic purpose to estimate the risks of impaired perfusion, such as osteonecrosis and nonunion. In one study of 36 patients, impaired femoral head perfusion was more common in patients with displaced fractures, although there was considerable overlap of perfusion pattern and fracture type [44]. The accuracy of predicting successful osseous union was 75% based on fracture morphology and improved incrementally to 89% on the basis of perfusion dynamics. Only 2 of 16 patients with nondisplaced fractures had osteonecrosis. A study from 2009 had similar results with 90% accuracy for prediction of successful fracture union on the basis of femoral head perfusion [45]. However, the study identified only 1 patient with a nondisplaced fracture with impaired femoral head perfusion and did not specify whether this patient went on to osteonecrosis, nor was the accuracy of predicting osteonecrosis on the basis of femoral head perfusion compared to that of the well-established Garden classification system. Given these findings, it is not clear if contrast-enhanced MRI offers significant advantages in the evaluation of the fractured hip compared to existing classification systems.


Acute Hip Pain Suspected Fracture PCAs

Acute Hip Pain Suspected Fracture PCAs. CT Pelvis and Hips CT has advantages over MRI in terms of speed as well as use in patients with significant confusion. There has been considerable investigation into the accuracy of noncontrast CT for detection of radiographically occult proximal femoral fractures, although these studies have been invariably retrospective in nature, have used inconsistent methodology, and at times produced conflicting results. In one study of 199 patients, CT was negative for fracture in 93 patients, and none were found to have undiscovered fractures at 4-month clinical follow-ups [34]. Another similar study with 68 patients found no missed fractures in 27 patients with negative CT scans, although it was not clear if clinical follow-up was as comprehensive [46]. However, a number of other studies have demonstrated potential limitations in the sensitivity of CT. For example, Haubro et al [26] found a sensitivity for CT of 87% compared with 100% for MRI, with CT missing 6 of 15 fractures. Another larger study of 129 cases compared MRI and CT for the diagnosis of both proximal femoral and pelvic fractures and found a sensitivity of 99% for MRI and 69% for CT using clinical outcomes and follow-up imaging as the gold standard [39]. This same study by Cabarrus et al [39] also found MRI to be substantially better at detecting soft-tissue abnormalities with 99% sensitivity for MRI and 13% sensitivity edema, and the differences in sensitivity for more significant injuries, such as hematoma or tendon avulsion, may be somewhat less. Several other similar studies comparing CT and MRI have also shown decreased sensitivity of CT with potential for missed fractures as well as changes in diagnosis and management when MRI is obtained after CT [24,47,48].


Acute Hip Pain Suspected Fracture PCAs

Acute Hip Pain Suspected Fracture PCAs. There is no relevant data to support the use of contrast-enhanced CT solely for the purpose of fracture detection following negative radiographs. However, if contrast-enhanced CT examination of the abdomen and pelvis is performed because of suspicion of concurrent intra-abdominal trauma, bone algorithm reconstruction of the pelvis and hips may be performed rather than performing a separate examination.


Acute Hip Pain Suspected Fracture PCAs

Acute Hip Pain Suspected Fracture PCAs. There is no relevant data to support the use of multiphase CT for the detection of fractures of the pelvis and proximal femur.


Acute Hip Pain Suspected Fracture PCAs

Acute Hip Pain Suspected Fracture PCAs. Dual-energy CT is a more recent technology that has the ability to produce virtual noncalcium images for the detection of bone marrow edema. Although the technology holds promise, diagnostic accuracy does not yet approach that of MRI, with an initial study by Reddy et al [49] demonstrating a sensitivity of 90% and specificity of 40% for nondisplaced femoral neck fractures. However, this may be a modality of emerging importance as technology improves.


Acute Hip Pain Suspected Fracture PCAs

Acute Hip Pain Suspected Fracture PCAs. US Hip The use of US for evaluation of the acutely painful hip has been evaluated in a single study of 10 patients with hip fractures [36]. Although US was able to identify trauma-related changes, such as joint effusion, with 100% sensitivity, specificity for fracture reached only 65%. The authors acknowledged that performance might further decrease for examinations performed by sonographers and radiologists not experienced with musculoskeletal US. For this document, it is assumed the procedure is performed and interpreted by an expert. Given the inability of US to comprehensively evaluate the bones and soft tissues of the pelvis, there is not enough evidence to support the role of US in the workup of radiographically occult hip fracture.


Acute Hip Pain Suspected Fracture PCAs

Acute Hip Pain-Suspected Fracture

Acute Hip Pain Suspected Fracture PCAs. Acute Hip Pain-Suspected Fracture


Acute Hip Pain Suspected Fracture PCAs

Acute Hip Pain Suspected Fracture PCAs. Bone Scan Hips Prior to the advent of MRI, a bone scan was the preferred test for radiographically occult proximal femoral fractures. However, as early as 1993, Rizzo et al [50] demonstrated MRI to be at least as accurate as bone scans and with substantially decreased time to diagnosis. A later study by Rubin et al [51] comparing bone scans and MRI demonstrated improved sensitivity and specificity of MRI relative to bone scans. Moreover, the bone scan group averaged an additional day to surgery.


Acute Hip Pain Suspected Fracture PCAs

Acute Hip Pain Suspected Fracture PCAs. Bone scintigraphy is a time-consuming process. Bone scans may be falsely negative for up to 72 hours from the time of injury, and false-positive scans are likewise common, related to osteoarthritis, soft-tissue injury, or any other process that may increase bone turnover [50]. It has been postulated that performing single-photon emission computed tomography may combine the sensitivity of bone scintigraphy with the spatial accuracy of CT, but there are no data to support this view. In current practice, the role of bone scans as a secondary line of imaging in patients with contraindications to MRI has largely been usurped by CT.


Acute Hip Pain Suspected Fracture PCAs

Acute Hip Pain Suspected Fracture PCAs. Supporting Documents The evidence table, literature search, and appendix for this topic are available at https://acsearch.acr.org/list. The appendix includes the strength of evidence assessment and the final rating round tabulations for each recommendation.


Acute Hip Pain Suspected Fracture PCAs

Acute Hip Pain Suspected Fracture PCAs. For additional information on the Appropriateness Criteria methodology and other supporting documents go to www.acr.org/ac.


Acute Hip Pain Suspected Fracture PCAs

Acute Hip Pain Suspected Fracture PCAs. Appropriateness Category Names and Definitions Relative Radiation Level Information Potential adverse health effects associated with radiation exposure are an important factor to consider when selecting the appropriate imaging procedure. Because there is a wide range of radiation exposures associated with different diagnostic procedures, a relative radiation level (RRL) indication has been included for each imaging


Stress Fatigue Insufficiency Fracture Including Sacrum Excluding Other Vertebrae PCAs. Introduction/Background Stress fractures occur in 2 varieties: 1) fatigue fractures resulting from repetitive submaximal stress on normal bone, resulting in a region of accelerated bone remodeling [1] and 2) insufficiency fractures due to normal activity on bones that are deficient in microstructure and/or mineralization [2]. At the microscopic level, repetitive overloading leads to increased osteoclastic activity that exceeds the rate of osteoblastic new bone formation. This results in bone weakening and microtrabecular disruption (stress injury) and eventually may lead to a cortical break (stress fracture). Stress fractures are encountered frequently and account for up to 20% of all injuries seen in sports medicine clinics [1,3-6]. The fatigue variation of stress fractures are particularly common in athletes participating in activities that require running and jumping, as well as in ballet dancers and military recruits [7-9]. Certain medical interventions such as radiation therapy and long-term osteoporosis treatment with bisphosphonates predispose patients to the insufficiency variation of stress fractures [10-12].


Stress Fatigue Insufficiency Fracture Including Sacrum Excluding Other Vertebrae PCAs. OR Discussion of Procedures by Variant Variant 1: Adult. Suspect stress fracture, excluding vertebrae. Initial imaging. Area of Interest: pelvis, ankle, elbow, femur, foot, forearm, hand, hip, humerus, knee, leg tib/fib, ribs, sacrum, shoulder, or wrist.


Stress Fatigue Insufficiency Fracture Including Sacrum Excluding Other Vertebrae PCAs. In the setting of new or repetitive athletic activity, fatigue fractures can develop in patients with normal bone. Furthermore, certain athletic activities often result in specific sites of fatigue fracture, such as olecranon process fractures in javelin throwers and baseball pitchers, proximal femur and tibial stress fractures in runners, and tarsal navicular stress fractures in basketball players [13-15]. Insufficiency fractures occur in patients with abnormal bone, be it from osteoporosis or irradiated bone, as typical examples. Insufficiency fractures also occur at fairly predictable


Stress Fatigue Insufficiency Fracture Including Sacrum Excluding Other Vertebrae PCAs. aThomas Jefferson University Hospital, Philadelphia, Pennsylvania. bResearch Author, Thomas Jefferson University Hospital, Philadelphia, Pennsylvania. cPanel Chair, Mayo Clinic Arizona, Phoenix, Arizona. dUniversity of Wisconsin School of Medicine and Public Health, Madison, Wisconsin. eMichigan State University, East Lansing, Michigan; American Academy of Orthopaedic Surgeons. fPenn State Health Milton S. Hershey Medical Center, Hershey, Pennsylvania. gMayo Clinic, Rochester, Minnesota. hHospital for Special Surgery, New York, New York. iBrigham & Women's Hospital, Boston, Massachusetts; Committee on Emergency Radiology-GSER. jMayo Clinic Arizona, Glendale, Arizona, Primary care physician. kUniversity of Virginia Health System, Charlottesville, Virginia. lMedical University of South Carolina, Charleston, South Carolina; North American Spine Society. mDuke University Medical Center, Durham, North Carolina. nUniversity of Missouri Health Care, Columbia, Missouri. oPenn State Milton S. Hershey Medical Center, Hershey, Pennsylvania and Uniformed Services University of the Health Sciences, Bethesda, Maryland. pSpecialty Chair, VA San Diego Healthcare System, San Diego, California.


Stress Fatigue Insufficiency Fracture Including Sacrum Excluding Other Vertebrae PCAs. 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.


Stress Fatigue Insufficiency Fracture Including Sacrum Excluding Other Vertebrae PCAs. Reprint requests to: publications@acr.org


Stress (Fatigue-Insufficiency) Fracture

Stress Fatigue Insufficiency Fracture Including Sacrum Excluding Other Vertebrae PCAs. Stress (Fatigue-Insufficiency) Fracture


Stress Fatigue Insufficiency Fracture Including Sacrum Excluding Other Vertebrae PCAs. sites, including the sacrum, supra-acetabular ilium, superior and inferior pubic rami, and pubic bone. These patients often present with intractable low back and/or pelvic pain [16].


Stress Fatigue Insufficiency Fracture Including Sacrum Excluding Other Vertebrae PCAs. Bone Scan Whole Body with SPECT or SPECT/CT Area of Interest The bone scan was regarded for many years as the reference standard for detecting stress-induced injuries and was valued for its sensitivity. Dobrindt et al [17] reported the sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of bone scintigraphy for detection of stress injuries as 92.9%, 73.8%, 83.3%, 78.0%, and 91.2%, respectively. Planar scintigraphy combined with single-photon emission CT (SPECT) is more accurate in diagnosing stress injuries than planar scintigraphy alone [18]. The objection to the studies quoting high accuracy for bone scintigraphy is that, in all of them, positive bone scintigraphy is taken as the reference standard for detecting stress fractures and therefore sensitivity is 100%. However, depending on the staging criteria for bone scintigraphy pattern, the abnormalities may in fact be stress reactions rather than actual stress fractures [19-21]. Nonetheless, bone scintigraphy shows stress fractures days to weeks earlier than radiographs in many instances and differentiates between osseous and soft tissue injury as well.


Stress Fatigue Insufficiency Fracture Including Sacrum Excluding Other Vertebrae PCAs. CT Area of Interest With IV Contrast There is no relevant literature to support the use of CT area of interest with intravenous (IV) contrast because it does not provide added information over noncontrast imaging with regard to stress injury.


Stress Fatigue Insufficiency Fracture Including Sacrum Excluding Other Vertebrae PCAs. CT Area of Interest Without and With IV Contrast There is no relevant literature to support the use of CT area of interest without and with IV contrast because it does not provide added information over noncontrast imaging with regard to stress injury.


Stress Fatigue Insufficiency Fracture Including Sacrum Excluding Other Vertebrae PCAs. CT Area of Interest Without IV Contrast CT is not supported for the initial imaging of suspected stress fractures but may offer an adjunct role when other imaging modalities are equivocal [22], particularly in the pelvis or sacrum. Although superior to radiography, it is less sensitive than nuclear scintigraphy or MRI [23]. The benefit of CT seems to lie in its specificity, ranging from 88% to 98% in a recent meta-analysis regarding accuracy of imaging modalities for lower extremity stress fractures, and thus may confirm a finding suspected to represent stress fracture on MRI [24]. CT may also be useful in cases where MRI results are equivocal.


Stress Fatigue Insufficiency Fracture Including Sacrum Excluding Other Vertebrae PCAs. MRI Area of Interest Without and With IV Contrast There is no relevant literature to support the use of MRI area of interest without and with IV contrast because it does not provide added information over noncontrast imaging with regard to stress injury.


Stress Fatigue Insufficiency Fracture Including Sacrum Excluding Other Vertebrae PCAs. MRI Area of Interest Without IV Contrast MRI demonstrates stress abnormalities as early as bone scintigraphy and with as much sensitivity [25-28]. In the absence of an actual stress fracture, stress reaction, or muscle/tendon injuries can be identified using fluid-sensitive sequences. Thus, MRI may be considerably more specific than scintigraphy [22,23]. The recent literature supports MRI as the procedure of choice for early diagnosis of both fatigue and insufficiency types of stress fractures, outperforming all other modalities [15,22,23,29-39]. Fluid-sensitive sequences are the favored initial sequence for MRI screening [40]. Short tau inversion recovery (STIR) and T1-weighted images demonstrate a fracture line surrounded by edema. MRI of an osseous stress injury contains prognostic as well as diagnostic information [41,42].


Stress Fatigue Insufficiency Fracture Including Sacrum Excluding Other Vertebrae PCAs. Radiography Area of Interest Radiographs are insensitive for stress fracture in the early stages of injury and in elderly patients with underlying osteoporosis. However, if symptoms have been present for at least 10 to 14 days, radiographs can achieve sensitivity of 30% to 70%, making them an effective screening tool [43]. If the findings on radiographs are conclusive for stress fracture, often no further imaging needs to be performed. Detection of osseous change is limited in areas covered by prominent overlapping soft tissue or bowel gas [31]. If the osseous reaction involves cortical bone, then endosteal/periosteal callus may be visible with or without a fracture line through the cortex. If the trabecular bone is involved, then stress fractures are often more subtle, progressing from patchy areas of increased density into linear areas of sclerosis, oriented perpendicular to the trabeculae.


Stress Fatigue Insufficiency Fracture Including Sacrum Excluding Other Vertebrae PCAs. US Area of Interest There is increasing evidence of the usefulness of ultrasound (US) in the early diagnosis of stress fractures of the extremities [44,45]. Although later US findings of stress fractures, including subcutaneous edema, periosteal thickening, cortical bone irregularity, local hyperemia [44-46], and periosteal callus are often nonspecific, these


Stress Fatigue Insufficiency Fracture Including Sacrum Excluding Other Vertebrae PCAs. Stress (Fatigue-Insufficiency) Fracture findings provide useful information in the setting of suspected stress fracture. Because US cannot evaluate the subcortical bone, trabecular stress fractures may be missed.


Stress Fatigue Insufficiency Fracture Including Sacrum Excluding Other Vertebrae PCAs. Variant 2: Adult. Suspect stress fracture, excluding vertebrae. Radiographs negative or indeterminate. Next imaging study. Area of Interest: pelvis, ankle, elbow, femur, foot, forearm, hand, hip, humerus, knee, leg tib/fib, ribs, sacrum, shoulder, or wrist.


Stress Fatigue Insufficiency Fracture Including Sacrum Excluding Other Vertebrae PCAs. Bone Scan Whole Body with SPECT or SPECT/CT Area of Interest Bone scintigraphy shows stress fractures days to weeks earlier than radiographs in many instances and differentiates between osseous and soft tissue injury as well. Although bone scan was regarded as the reference standard examination for many years, MRI demonstrates stress abnormalities as early as bone scintigraphy and with as much sensitivity [25-28]. Because standard planar whole body bone scintigraphy is often nonspecific and supplemental imaging is frequently required, there is consensus in the literature that MRI should supersede bone scintigraphy as the imaging examination of choice for suspected stress fracture when radiographs are negative [31].


Stress Fatigue Insufficiency Fracture Including Sacrum Excluding Other Vertebrae PCAs. CT Area of Interest With IV Contrast There is no relevant literature to support the use of CT area of interest with IV contrast because it does not provide added information over noncontrast imaging with regard to stress injury.


Stress Fatigue Insufficiency Fracture Including Sacrum Excluding Other Vertebrae PCAs. CT Area of Interest Without IV Contrast CT is not supported as the next imaging study for suspected stress fractures following radiographs but may offer an adjunctive role when other imaging modalities are equivocal [22]. Although superior to radiography, it is less sensitive than nuclear scintigraphy and MRI [23]. CT is useful in cases where MRI results are equivocal.


Stress Fatigue Insufficiency Fracture Including Sacrum Excluding Other Vertebrae PCAs. MRI Area of Interest Without IV Contrast MRI outperforms radiography, bone scintigraphy, and CT with recent literature supporting MRI as the procedure of choice for making an early diagnosis of both fatigue and insufficiency fractures [15,22,23,29-39]. MRI of an osseous stress injury contains prognostic as well as diagnostic information [41,42].


Stress Fatigue Insufficiency Fracture Including Sacrum Excluding Other Vertebrae PCAs. Radiography Area of Interest Repeat In 10-14 Days Short-term (10-14 days) follow-up radiographs are more sensitive than initial radiographs secondary to overt bone reaction in the location of the stress fracture. Follow-up radiographic sensitivity is reported to be 30% to 70% [43]. Detection of osseous change is more limited in areas covered by prominent overlapping soft tissue [31]. If the osseous reaction involves cortical bone, then endosteal/periosteal callus may be visible with or without a fracture line through the cortex. If the trabecular bone is involved, then stress fractures are often more subtle, progressing from patchy areas of increased density into linear areas of sclerosis, oriented perpendicular to the trabeculae.


Stress Fatigue Insufficiency Fracture Including Sacrum Excluding Other Vertebrae PCAs. US Area of Interest There is increasing evidence of the usefulness of US in the early diagnosis of stress fractures of the extremities [44,45]. Although later US findings of stress fractures, including subcutaneous edema, periosteal thickening, cortical bone irregularity, local hyperemia [44-46], and periosteal callus are often nonspecific, these findings provide useful information in the setting of suspected stress fracture. Because US cannot evaluate the subcortical bone, trabecular stress fractures may be missed.


Stress Fatigue Insufficiency Fracture Including Sacrum Excluding Other Vertebrae PCAs. Variant 3: Adult. Suspect pelvis or hip or sacrum stress fracture. Pregnant patient. Radiographs negative or indeterminate. Next imaging study. Area of Interest: pelvis, hip, or sacrum.


Stress Fatigue Insufficiency Fracture Including Sacrum Excluding Other Vertebrae PCAs. Pelvic and hip insufficiency fractures have varied presentations and often insidious onset. Patients frequently present with intractable lower back or pelvic pain, with loss of mobility, independence, and symptom exacerbation


Stress Fatigue Insufficiency Fracture Including Sacrum Excluding Other Vertebrae PCAs. Stress (Fatigue-Insufficiency) Fracture with weight bearing [47]. Insufficiency fractures occur in patients with abnormal bone, be it from osteoporosis, irradiated bone, or resumption of activity.


Stress Fatigue Insufficiency Fracture Including Sacrum Excluding Other Vertebrae PCAs. Imaging findings of pregnancy-related sacral fractures are similar to sacral insufficiency fractures related to involutional osteoporosis, with the exception that patients will be in their reproductive years and in the last trimester of pregnancy or recently postpartum [56,57].


Stress Fatigue Insufficiency Fracture Including Sacrum Excluding Other Vertebrae PCAs. Bone Scan Whole Body with SPECT or SPECT/CT Area of Interest Bone scintigraphy and CT are both associated with radiation exposure to the fetus in a pregnant patient. For reference, the approximate mean fetal absorbed dose from a pelvis radiograph is 1.1 mGy, from a pelvis CT is 25 mGy, and from a bone scintigraphy is 4.6 mGy (early in pregnancy) and 1.8 mGy (at 9 months estimated gestational age) [62]. Because bone scintigraphy is often nonspecific and supplemental imaging is frequently required, there is consensus in the literature that cross-sectional imaging should supersede bone scintigraphy as the imaging of choice for suspected insufficiency fracture when the radiograph is negative, regardless of the risks of radiation exposure [31].


Stress Fatigue Insufficiency Fracture Including Sacrum Excluding Other Vertebrae PCAs. CT Area of Interest Without and With IV Contrast There is no relevant literature to support the use of CT area of interest without and with IV contrast because it does not provide added information over noncontrast imaging with regard to stress injury.


Stress Fatigue Insufficiency Fracture Including Sacrum Excluding Other Vertebrae PCAs. CT Area of Interest Without IV Contrast CT and bone scintigraphy are both associated with radiation exposure to the fetus in a pregnant patient [62]. Therefore, MRI is preferred.


Stress Fatigue Insufficiency Fracture Including Sacrum Excluding Other Vertebrae PCAs. MRI Area of Interest Without and With IV Contrast There is no relevant literature to support the use of MRI area of interest without and with IV contrast because it does not provide added information over noncontrast imaging with regard to stress injury.


Stress Fatigue Insufficiency Fracture Including Sacrum Excluding Other Vertebrae PCAs. MRI Area of Interest Without IV Contrast Given the importance of recognizing these high-risk fractures in the femoral head and neck, MRI is the preferred second-line study after initial negative radiographs to prevent delayed diagnosis. MRI does not use ionizing radiation, has excellent sensitivity, and allows for definitive diagnosis. MRI typically demonstrates linear T1 and T2 hypointense signal, representing fracture lines, and T1 hypointense and T2 hyperintense signal in the surrounding bone marrow, representing associated edema. MRI demonstrates stress abnormalities as early as bone scintigraphy and with as much sensitivity [25-28].


Stress Fatigue Insufficiency Fracture Including Sacrum Excluding Other Vertebrae PCAs. Stress (Fatigue-Insufficiency) Fracture In addition to confirming a suspected stress fracture, MRI may also demonstrate other reasons for occult pelvic pain, such as soft tissue abnormalities or the subchondral hip or supra-acetabular stress fractures described in some patients with osteoporosis [57].


Stress Fatigue Insufficiency Fracture Including Sacrum Excluding Other Vertebrae PCAs. Radiography Area of Interest Repeat In 10-14 Days A follow-up radiographic examination has increased sensitivity compared to initial radiographs [43] but is less sensitive than MRI.


Stress Fatigue Insufficiency Fracture Including Sacrum Excluding Other Vertebrae PCAs. US Area of Interest There is increasing evidence of the usefulness of US in the early diagnosis of stress fractures of the distal extremities [44,45] and may allow visualization of posterior sacral fractures without the risk of ionizing radiation. However, definitive diagnosis of suspected hip or pelvic fractures should not be delayed by choosing US as the second-line study following negative or indeterminate radiographs, considering that additional imaging may be required following a negative or US indeterminate examination.


Stress Fatigue Insufficiency Fracture Including Sacrum Excluding Other Vertebrae PCAs. Patients at high-risk for fracture completion include patients with osteoporosis, those on bisphosphonate therapy, and athletes. Stress fractures in this population that are not identified and managed in a timely fashion can progress to more serious fractures and complications (eg, risk of fatty emboli in completed femoral shaft fractures). Preventive strategies, including identifying and modifying risk factors, may help deter progression to complete fracture [42,63,64].


Stress Fatigue Insufficiency Fracture Including Sacrum Excluding Other Vertebrae PCAs. Certain stress fractures are considered high risk based on a tendency for nonunion or delayed union. High-risk stress fractures include the anterior tibial diaphysis, lateral femoral neck and femoral head, patella, medial malleolus, navicular, fifth metatarsal base, proximal second metatarsal, tibial hallux sesamoid, and talus [65].


Stress Fatigue Insufficiency Fracture Including Sacrum Excluding Other Vertebrae PCAs. CT Area of Interest With IV Contrast There is no relevant literature to support the use of CT area of interest with IV contrast because it does not provide added information over noncontrast imaging with regard to stress injury.


Stress (Fatigue-Insufficiency) Fracture

Stress Fatigue Insufficiency Fracture Including Sacrum Excluding Other Vertebrae PCAs. Stress (Fatigue-Insufficiency) Fracture


Stress Fatigue Insufficiency Fracture Including Sacrum Excluding Other Vertebrae PCAs. CT Area of Interest Without IV Contrast CT is not supported as the next imaging study for suspected stress fractures following radiographs but may offer an adjunctive role when other imaging modalities are equivocal [22]. Although superior to radiography, it is less sensitive than nuclear scintigraphy or MRI [23]. The benefit of CT seems to lie in its specificity, ranging from 88% to 98% in a recent meta-analysis regarding accuracy of imaging modalities for lower extremity stress fractures and thus may confirm a finding suspected to represent stress fracture on MRI [24].


Stress Fatigue Insufficiency Fracture Including Sacrum Excluding Other Vertebrae PCAs. MRI Area of Interest Without IV Contrast MRI is beneficial after initial negative radiographs to prevent delayed diagnosis. MRI has excellent sensitivity, and it allows for definitive diagnosis. MRI typically demonstrates linear T1 and T2 hypointense signal, representing fracture lines, and T1 hypointense and T2 hyperintense signal in the surrounding bone marrow, representing associated edema. MRI demonstrates stress abnormalities as early as bone scintigraphy but with more specificity [25-28].


Stress Fatigue Insufficiency Fracture Including Sacrum Excluding Other Vertebrae PCAs. US Area of Interest There is increasing evidence of the usefulness of US in the early diagnosis of stress fractures of the distal extremities [44,45] and may allow for visualization of posterior sacral fractures. However, definitive diagnosis of suspected hip or pelvic fractures should not be delayed by choosing US as the second-line study following negative or indeterminate radiographs, considering that additional imaging may be required following a negative or US indeterminate examination.


Stress Fatigue Insufficiency Fracture Including Sacrum Excluding Other Vertebrae PCAs. Variant 5: Adult. Suspect subchondral stress fracture at an extremity joint. Radiographs negative or indeterminate. Next imaging study. Area of Interest: pelvis, ankle, elbow, femur, foot, forearm, hand, hip, humerus, knee, leg tib/fib, shoulder, or wrist.