Lower Extremity Arterial Claudication Imaging Assessment for Revascularization. Some technical problems limit the utility of CE-MRA for imaging PAD. Challenges may include image quality related to low signal-to-noise ratio, limited spatial resolution, motion artifacts, long acquisition times, and loss of signal in arterial segments within metal stents or adjacent to metallic clips or prosthetic joints. Some of these problems have been addressed successfully with the use of newer imaging sequences and newer stent designs.


Lower Extremity Arterial Claudication Imaging Assessment for Revascularization. MRA Abdomen and Pelvis with Bilateral Lower Extremity Runoff Without IV Contrast Noncontrast MRA techniques predate CE-MRA in their development. However, long acquisition time and motion artifacts limit the use of these techniques in the abdomen and peripheral arteries [33]. To that end, recent


Lower Extremity Arterial Claudication

Lower Extremity Arterial Claudication Imaging Assessment for Revascularization. Lower Extremity Arterial Claudication


Lower Extremity Arterial Claudication Imaging Assessment for Revascularization. advancements in noncontrast MRA techniques for imaging PAD have expanded the sequence options from time- of-flight and phase-contrast imaging to include electrocardiogram-gated fresh-blood partial Fourier fast spin echo, balanced steady-state free precession, and arterial spin labeling [33]. Two alternative approaches using balanced steady state for peripheral noncontrast MRA applications include flow-sensitive dephasing and quiescent-interval single shot [30,33-35]. When compared with bolus-chase and time-resolved gadolinium-enhanced MRA, initial studies of fresh-blood imaging of the tibial and pedal arteries have provided accurate imaging when technically successful. Overall, these methods are being increasingly adopted for patients with severe renal insufficiency at risk of developing nephrogenic systemic fibrosis.


Lower Extremity Arterial Claudication Imaging Assessment for Revascularization. Some technical problems limit the utility of noncontrast MRA for imaging PAD. Challenges may include image quality related to low signal-to-noise ratio, limited spatial resolution, motion artifacts, long acquisition times, unreliable visualization of lesions with high flow and turbulence (excessive signal loss at regions of high-grade stenoses), nonvisualization of patent vessel segments with reversed blood flow, and loss of signal in arterial segments within metal stents or adjacent to metallic clips or prosthetic joints. Some of these problems have been addressed successfully with the use of newer imaging sequences. With the newer noncontrast techniques, cardiac arrhythmia can impair image quality, limiting evaluation of the distal tibial and pedal arteries. Although useful tools to improve image quality have been suggested, larger-scale trials are required for evaluation of small-vessel PAD with noncontrast MRA [29,36].


Lower Extremity Arterial Claudication Imaging Assessment for Revascularization. MRA Lower Extremity Without and With IV Contrast MRA of one or both lower extremities can be performed without imaging the abdomen and pelvis when aortoiliac disease is not a concern or the state of the aorta and iliac arteries is already known.


Lower Extremity Arterial Claudication Imaging Assessment for Revascularization. CE-MRA techniques continue to evolve and improve. Three-dimensional imaging, contrast enhancement with gadolinium, subtraction, cardiac gating, bolus chase, parallel imaging, optimized K-space filling, 3T magnet strength, and improved coil technology have led to improved temporal resolution, spatial resolution, and signal-to- noise ratio in CE-MRA. Its sensitivity and specificity for detection of stenoses >50% are now in the 90% to 100% range [25-27]. Unlike with CTA, the presence of calcium in small vessels does not result in a CE-MRA artifact [28]. Furthermore, dedicated time-resolved CE-MRA of the tibial and pedal arteries significantly increases diagnostic accuracy of tibial and pedal lesions compared with standard multistation CE-MRA. Time-resolved CE- MRA also reduces insufficient arterial filling and venous contamination, which are common limitations of standard multistation CE-MRA [28]. Although CE-MRA has not supplanted angiography as a reference standard, one small study demonstrated that 3T CE-MRA with calf compression (to prevent venous contamination) resulted in better visualization of tibial arteries than DSA [29]. For these reasons, CE-MRA is ideally suited for patients at high risk for calcification of the tibial and pedal arteries, particularly patients with diabetes and patients >80 years of age [28,30].


Lower Extremity Arterial Claudication Imaging Assessment for Revascularization. In comparison with duplex US, CE-MRA is more accurate for detecting and quantifying significant stenoses and for preoperative planning [31]. In a randomized controlled trial comparison with duplex US, CE-MRA for the initial imaging workup of patients with PAD reduced the need for additional imaging [32]. In a meta-analysis comparison to CTA, CE-MRA had equivalent sensitivity and specificity for detecting arterial lesions from the aorta to the tibial arteries in patients with intermittent claudication [26].


Lower Extremity Arterial Claudication Imaging Assessment for Revascularization. Noncontrast MRA techniques predate CE-MRA in their development. However, long acquisition time and motion artifacts limit the use of these techniques in the abdomen and peripheral arteries [33]. To that end, recent advancements in noncontrast MRA techniques for imaging PAD have expanded the sequence options from time- of-flight and phase-contrast imaging to include electrocardiogram-gated fresh-blood partial Fourier fast spin echo, balanced steady-state free precession, and arterial spin labeling [33]. Two alternative approaches using balanced steady state for peripheral noncontrast MRA applications include flow-sensitive dephasing and quiescent-interval single shot [30,33-35]. When compared with bolus-chase and time-resolved gadolinium-enhanced MRA, initial studies of fresh-blood imaging of the tibial and pedal arteries have provided accurate imaging when technically successful. Overall, these methods are being increasingly adopted for patients with severe renal insufficiency at risk of developing nephrogenic systemic fibrosis.


Lower Extremity Arterial Claudication


Lower Extremity Arterial Claudication Imaging Assessment for Revascularization. MRA Lower Extremity Without IV Contrast MRA of one or both lower extremities can be performed without imaging the abdomen and pelvis when aortoiliac disease is not a concern or the state of the aorta and iliac arteries is already known.


Lower Extremity Arterial Claudication Imaging Assessment for Revascularization. US Duplex Doppler Lower Extremity Duplex US of the extremities can be used to identify the location, degree, and extent of stenosis to the level of the knee [37]. Although duplex US includes images in grayscale or in color or power Doppler, the clinically relevant information derived from duplex studies has been validated from analysis of the velocity of blood flow.


Lower Extremity Arterial Claudication Imaging Assessment for Revascularization. The sensitivity and specificity for the diagnosis of stenoses >50% in diameter from the iliac arteries to the popliteal arteries are each approximately 90% to 95% [37-39]. Accuracy of the duplex examination depends on the ability of the technique to visualize the vessel adequately. The use of color improves accuracy [40]. Accuracy is diminished in examinations of the iliac arteries if bowel gas or tortuosity obscures the iliac vessels. Dense calcification can also obscure flow, particularly if flow is slow. Accuracy of duplex US is also decreased in the setting of multiple sequential lesions [41].


Lower Extremity Arterial Claudication Imaging Assessment for Revascularization. Duplex US has been established as a useful surveillance tool for arterial bypass grafts with established criteria for graft stenosis and thresholds for reintervention [42]. However, evidence and standards for duplex US surveillance after endovascular treatment are lacking, although duplex US is commonly used for this indication [42]. In comparison with CE-MRA, duplex US is less accurate for detecting significant stenoses and for preoperative planning [31]. In a randomized controlled trial comparison with CE-MRA, duplex US for the initial imaging workup of patients with PAD increased the need for additional imaging [32]. CTA is more clinically useful than duplex US [21].


Lower Extremity Arterial Claudication Imaging Assessment for Revascularization. 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.


Lower Extremity Arterial Claudication Imaging Assessment for Revascularization. For additional information on the Appropriateness Criteria methodology and other supporting documents go to www.acr.org/ac.


Growth Disturbances Risk of Fetal Growth Restriction. Introduction/Background Fetal growth restriction (FGR) is an important complication of pregnancy and is associated with significant risks of perinatal morbidity and mortality. A small-for-gestational-age (SGA) fetus is defined as a fetus whose estimated fetal weight (EFW) is below the 10th percentile for gestational age [1,2]. FGR implies an SGA fetus that has not reached its growth potential as measured by EFW. Although some SGA fetuses are constitutionally small and not at risk for perinatal morbidity and mortality [3], others are affected by a variety of maternal or placental conditions that lead to uteroplacental insufficiency and potential adverse outcomes, such as neurodevelopmental delay [4]. Given the difficulty in differentiating fetuses who are constitutionally SGA from those with FGR, it is typical for all fetuses with an EFW below the 10th percentile to be treated comparably. Finally, some fetuses may have an EFW at or above the 10th percentile but may also be at risk for adverse outcomes because of their suboptimal rate of growth [5,6]. The diagnosis of FGR is based upon an accurate assessment of gestational age. If gestational age is uncertain, then repeat evaluation to ensure appropriate growth velocity is recommended. Many different fetal biometric growth curves exist, and it is preferable to use the growth curve that most approximates the population being studied.


Growth Disturbances Risk of Fetal Growth Restriction. The American College of Radiology seeks and encourages collaboration with other organizations on the development of the ACR Appropriateness Criteria through society representation on expert panels. Participation by representatives from collaborating societies on the expert panel does not necessarily imply individual or society endorsement of the final document.


Growth Disturbances Risk of Fetal Growth Restriction. Reprint requests to: publications@acr.org


Growth Disturbances Risk of Fetal Growth Restriction. US Pregnant Uterus Biophysical Profile The BPP is the mainstay of fetal well-being evaluation and consists of four parameters variably sensitive to the acute exposure of the fetus to hypoxemia: fetal breathing movements, fetal limb and body movements, fetal tone, and amniotic fluid volume (which is thought to be more of an indicator of chronic hypoxemia). The NST, which is sometimes included with the BPP as a fifth component, can be used alone as a test of acute fetal well-being status, but it is often coupled with amniotic fluid measurement, a valuable reflection of fetal hypoxemic exposure over the previous week. Each of the four (or five) components of the BPP receives a score of 0 or 2, leading to a maximum score of 8 (or 10). Scores of 8 (or 10) are strong indicators of a well-compensated fetus [27]. For those at risk for fetal demise, testing strategies usually evaluate one or more of the fetal well-being parameters at least weekly. For the well-being of those fetuses at highest risk for fetal demise, testing can often occur twice weekly or even daily, from the point of postnatal viability until delivery is indicated. Amniotic fluid volume is usually assessed at least weekly, but may be evaluated more often if it is approaching severely low levels. Daily or even more frequent testing by BPP or NST may be indicated in critical situations. To our knowledge, there are no trials evaluating the use of the BPP as an initial procedure among those at low risk for FGR.


Growth Disturbances Risk of Fetal Growth Restriction. US Duplex Doppler Velocimetry Fetal Umbilical Artery Although much research has centered on the use of Doppler velocimetry of the fetal umbilical artery among fetuses with known FGR, little work has been done among fetuses in women who are felt to be at low risk for FGR. In fact, umbilical artery Doppler velocimetry has not been shown to be a useful screening tool for FGR [31].


Growth Disturbances Risk of Fetal Growth Restriction. US Duplex Doppler Velocimetry Fetal Middle Cerebral Artery To our knowledge, there are no trials evaluating the use of Doppler velocimetry of the fetal middle cerebral artery as an FGR screening tool in low-risk women.


Growth Disturbances Risk of Fetal Growth Restriction. US Duplex Doppler Velocimetry Ductus Venosus To our knowledge, there are no trials evaluating the use of Doppler velocimetry of the fetal ductus venosus as a FGR screening tool in low-risk women.


Growth Disturbances Risk of Fetal Growth Restriction. Variant 2: Growth disturbance. High risk for fetal growth restriction. Initial evaluation. As discussed above, the mainstay for evaluation of a fetus for FGR is assessment of fetal biometry. This typically occurs during transabdominal US of the uterus. If a fetus is identified as having FGR, confirmation of fetal well- being, such as with a BPP, is necessary. Doppler interrogation of the umbilical artery is a useful tool for timing of delivery for those with FGR.


Growth Disturbances Risk of Fetal Growth Restriction. US Pregnant Uterus Transabdominal As opposed to those at low-risk for FGR, those at high-risk for FGR are especially important to identify. As discussed above, US is currently the primary method of identification of fetuses with FGR. Many various historical and clinical factors can suggest FGR, but US-derived fetal biometry is the only current means to confirm a clinical suspicion for FGR.


Growth Disturbances Risk of Fetal Growth Restriction. US Duplex Doppler Velocimetry Fetal Umbilical Artery Fetal umbilical artery Doppler velocimetry has garnered the most research for those with known or suspected FGR. Alfirevic et al [35] in a meta-analysis of 20 controlled trials of umbilical artery Doppler US found that management incorporating umbilical artery duplex Doppler was associated with improved perinatal outcome in high-risk pregnancies, reduced antenatal admissions, inductions of labor, and Cesarean delivery for fetal distress, and reduced odds of perinatal death by 38%.


Growth Disturbances Risk of Fetal Growth Restriction. Variant 3: Established fetal growth restriction. Follow-up evaluation. US Pregnant Uterus Transabdominal Once a diagnosis of FGR has been considered and/or made, serial evaluation of fetal growth is performed to assess the degree to which the fetus is compensating within this abnormal milieu [1,8,11]. Decreasing percentile growth would suggest the need for more intensive monitoring for assessment of fetal well-being or perhaps delivery depending upon clinical parameters, including gestational age.


Growth Disturbances Risk of Fetal Growth Restriction. US Duplex Doppler Velocimetry Fetal Middle Cerebral Artery In a systematic review, middle cerebral artery Doppler indexes, which were thought to indicate cerebral redistribution, suggested that SGA fetuses with abnormal middle cerebral artery Doppler velocimetry were associated with neurodevelopmental problems at follow-up of SGA fetuses. The authors called for more adequately controlled studies with long-term follow-up before clear conclusions could be drawn [46]. Among


Growth Disturbances Risk of Fetal Growth Restriction. Summary of Recommendations Variant 1: US pregnant uterus transabdominal is usually appropriate for the initial imaging of pregnant women who are at low risk for FGR. Variant 2: US pregnant uterus transabdominal is usually appropriate for the initial imaging of pregnant women who are at high risk for FGR. For those who are found to have growth restriction, US duplex Doppler velocimetry fetal umbilical artery and US pregnant uterus BPP are usually appropriate. Variant 3: US pregnant uterus BPP, US pregnant uterus transabdominal, US duplex Doppler velocimetry fetal umbilical artery, US duplex Doppler velocimetry ductus venosus, and US duplex Doppler velocimetry fetal middle cerebral artery are usually appropriate for follow-up evaluation in pregnant women with established FGR. These procedures are complementary (ie, all tests should be performed).


Growth Disturbances Risk of Fetal Growth Restriction. 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.


Growth Disturbances Risk of Fetal Growth Restriction. For additional information on the Appropriateness Criteria methodology and other supporting documents go to www.acr.org/ac.


Growth Disturbances Risk of Fetal Growth Restriction. ACR-ACOG-AIUM-SRU Practice Parameter for the Performance of Obstetrical Ultrasound [52] ACR Manual on Contrast Media [53] ACR Guidance Document for MR Safe Practices [54]


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. Introduction/Background Atrial fibrillation (AF) is the most common cardiac arrhythmia, affecting 3% of the population [1,2], predisposing to circulatory stasis and formation of left atrial (LA) thrombi, mostly in the LA appendage (LAA) [1,3,4].


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. Endovascular treatment of AF continues to evolve, with favorable outcomes. Catheter ablation eliminates the electrical connection between the left atrium and ectopic pulmonary venous arrhythmogenic foci [5] and can be used to eliminate substrate for reentry within or adjacent to areas of LA fibrosis [6]. Imaging for preprocedural planning for LA ablation has been shown to improve success rate of procedures, minimize complications, exclude contraindications for the procedure, and minimize the risk of AF recurrence [7]. Endovascular device occlusion/closure of the LAA is used to reduce LAA thrombi from embolizing into the systemic circulation [8-10]. Cardioversion aims to restore a patient to normal sinus rhythm, and in such patients, precardioversion imaging is used to exclude the presence of LAA thrombus because up to 7% of patients have atrial thrombi despite anticoagulation regimens [7].


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. The document discusses imaging guidelines for the following preprocedural clinical tasks in patients needing endovascular treatment or cardioversion of AF: 1) before catheter ablation, to determine the anatomy of the pulmonary veins, the size of their ostia if using balloon technology, and to determine the relationship of the left atrium to adjacent structures (such as the esophagus) to minimize complications and exclude thrombi; 2) before LAA occlusion to assess LAA morphology and dimensions for device selection, exclude LAA thrombi, assess LAA relationship to adjacent cardiac, and extracardiac structures to aid in determining feasibility and preprocedural planning; and 3) before cardioversion, to exclude LA/LAA thrombi.


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. aUniversity of Michigan, Ann Arbor, Michigan. bResearch Author, Allegheny Health Network Imaging Institute, Pittsburgh, Pennsylvania. cPanel Chair, Massachusetts General Hospital, Boston, Massachusetts. dUniversity of Utah, Department of Radiology and Imaging Sciences, Salt Lake City, Utah; Commission on Nuclear Medicine and Molecular Imaging. eCleveland Clinic, Cleveland, Ohio; Cardiology expert. fEmory University, Atlanta, Georgia. gOregon Health & Science University, Portland, Oregon. hChristianaCare Health System, Newark, Delaware; Society of General Internal Medicine. iUniversity of California San Francisco, San Francisco, California. jVA Palo Alto Health Care System, Palo Alto, California and Stanford University, Stanford, California. kInnovation Health Services, Norfolk, Virginia. lMassachusetts General Hospital, Boston, Massachusetts. mHospital of the University of Pennsylvania, Philadelphia, Pennsylvania; Heart Rhythm Society. nSanger Heart and Vascular Institute, Charlotte, North Carolina; Society of Cardiovascular Computed Tomography. oIndiana University School of Medicine, Indianapolis, Indiana; American College of Physicians. pDuke University Medical Center, Durham, North Carolina. qOhio State University, Columbus, Ohio; Society for Cardiovascular Magnetic Resonance. rSpecialty Chair, Duke University Medical Center, Durham, North Carolina.


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. 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.


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. Reprint requests to: publications@acr.org


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. 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.


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. For the purposes of the document, CTA chest may be performed with electrocardiogram (ECG) gating, triggering, high pitch dual source acquisition, or nongated acquisition depending on site technology and experience. This is in distinction to CT heart, which is routinely performed with ECG gating and is often limited in z-axis to only cover the heart. Similarly, MR angiography (MRA) chest may be an ECG-gated or nongated acquisition and may be performed with or without contrast. The 3-D reconstructions and renderings are an essential element for MRA.


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. Discussion of Procedures by Variant Variant 1: Adult. Atrial fibrillation, atrial tachycardia, or atypical atrial flutter. Preprocedural planning prior to left atrial ablation. Arteriography Coronary Invasive coronary arteriography provides assessment of coronary artery disease. There is no relevant literature to support the use of routine coronary arteriography to guide preprocedural planning before LA ablation procedure.


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. Catheter Venography Pulmonary Catheter venography provides assessment of the pulmonary veins. There is little evidence in the literature supporting the use of catheter venography for routine preprocedural planning for atrial arrhythmia ablation. One retrospective review evaluated periprocedural 3-D rotational angiography in 547 consecutive patients undergoing ablation via direct contrast injection into either the right or left atrium, with or without simultaneous oral contrast administration for esophageal mapping [15]. With the availability of electroanatomic mapping systems, there is no added benefit or literature supporting the use of catheter venography during atrial arrhythmia ablation.


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. CT Chest With IV Contrast There is no relevant literature to support the use of CT chest with intravenous (IV) contrast to guide preprocedural planning before LA ablation.


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. CT Chest Without and With IV Contrast There is no relevant literature to support the use of CT chest without and with IV contrast to guide preprocedural planning before LA ablation.


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. CT Chest Without IV Contrast A single prospective study of 50 patients evaluated with unenhanced chest CT found no statistically significant difference in procedural times and ablation success rate [16]. This is limited by the population size and paucity of additional supporting data. Integration of unenhanced CT with electroanatomic mapping cannot be adequately performed [16], and evaluation for contraindications such as thrombus is not possible.


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. CT Heart Function and Morphology With IV Contrast ECG-gated cardiac multidetector CT (MDCT) can assess left atrium, LAA, and pulmonary venous anatomy. In a study including 1,040 consecutive patients who underwent pulmonary vein catheter ablation, cardiovascular anatomic variants were identified on gated-CT in 18.7% of cases [5]. For patients undergoing repeat ablation procedures, CT can assess sites of pulmonary vein stenosis or occlusion caused by a prior procedure. It also provides information on adjacent thoracic structures, including the esophagus, and facilitates electroanatomic mapping for preprocedural planning for ablation.


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. Left Atrial Procedures in Atrial Fibrillation CT heart has also been evaluated in assessing thrombi before various LA procedures. With specific regard to the preablation setting, the specificity and negative predictive value (NPV) of a single acquisition CT (without delayed or prone imaging) have been reported to be 88% and 100%, respectively, based on a study of 51 patients when compared with transesophageal echocardiography (TEE) [17]. The diagnostic accuracy of CT for thrombus can be further improved by using a delayed phase or prone position [18]. In a small study of 70 patients, the specificity and positive predictive value of CT increased from 84% and 15% to 100% and 100%, respectively, by adding a delayed phase [19]. The high NPV can be used to decrease the usefulness of TEE, so that it is selectively used only when CT is positive. Hong et al [20] found that patients who underwent cardiac MDCT followed by routine TEE had no significant difference in periprocedural stroke incidence when compared with selective TEE (0.2% incidence in each group, P > .99); the sensitivity and NPV of CT were 100% and 100%, respectively, in this study. This strategy of selective use of TEE was also assessed during the COVID-19 pandemic, and the study showed no significant difference in periprocedural thromboembolic events between routine TEE versus selective use of TEE guided by CT (0% versus 0.4%, P = .33, n = 637) [21].


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. Cardiac CT can assess LA size, which may help guide patient management as increased LA volume is an independent predictor of arrhythmia recurrence (n = 103; hazard ratio [HR], 1.011/mL; 95% confidence interval [CI], 1.003-1.020; P = .002) [22].


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. CTA Coronary Arteries With IV Contrast CTA coronary arteries is used to assess coronary arterial disease. There is no relevant literature supporting the routine use of CTA coronary arteries with IV contrast to guide preprocedural planning before LA ablation. This can also be technically challenging due to irregular heart rhythm in these patients. Although not routinely recommended, if the specific clinical scenario requires coronary arterial evaluation in addition to preablation planning, the study may be performed as a CTA coronary examination and left atrium and pulmonary veins can be assessed simultaneously.


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. MRA Chest Without and With IV Contrast MRA without and with IV contrast can assess LA size, pulmonary venous anatomy, and thrombus. Both standard contrast-enhanced and dynamic time-resolved contrast-enhanced MRA (the latter performed with a lower gadolinium agent contrast dose) can assess the LA and pulmonary venous anatomy [26,27]. A recent comparison of these 2 acquisitions in 50 patients showed that time-resolved MRA has significantly higher overall image quality (P < .0001) [27]. MRA with IV contrast can identify LA/LAA thrombi with an accuracy of 94.3%, a sensitivity of 66.7%, and a specificity of 95.2% compared with TEE [28].


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. MRA Chest Without IV Contrast Noncontrast enhanced MRA using 2-D and 3-D balanced steady-state free-precession (b-SSFP) can assess LA size and pulmonary venous anatomy, although it cannot reliably assess for thrombus. It may be a feasible alternative for preablation planning in patients who cannot receive IV contrast [29,30]. Despite an overall lower image quality, 2- D b-SSFP MRA yielded adequate LA and pulmonary vein anatomical information and adequate electroanatomic


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. Left Atrial Procedures in Atrial Fibrillation integration when compared with contrast-enhanced CT in 54 patients, 27 scanned with each modality [29]. Further supporting data are scarce.


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. MRA Coronary Arteries Without and With IV Contrast MRA coronary artery examination can assess proximal coronary artery anatomy. There is no relevant literature to support the use of MRA coronary arteries without and with IV contrast to guide preprocedural planning before LA ablation.


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. MRA Coronary Arteries Without IV Contrast MRA coronary artery examination can assess proximal coronary artery anatomy. There is no relevant literature to support the use of MRA coronary arteries without IV contrast to guide preprocedural planning before LA ablation.


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. MRI Heart Function and Morphology Without and With IV Contrast MRI heart with IV contrast can assess chamber size, presence of LA/LAA thrombi, and atrial fibrosis. However, for pulmonary vein anatomy and measurements, it requires a complementary procedure (ie, a simultaneous 3-D acquisition [MRA]). In a study that matched 400 patients to either preprocedural cardiac CT or cardiac MR (CMR), procedural characteristics (fluoroscopy time, procedure duration, pulmonary veins identified, targeted, and isolated) and arrhythmia recurrence rates were not significantly different [31]. In 2 studies, MRI heart was shown to have more accurate and reproducible measurements of LA volume, which, when increased, is an independent predictor or postablation recurrence [31,32]. Among various MR sequences, long inversion time-delayed enhanced CMR has the highest reported diagnostic accuracy (99.2%), sensitivity (100%), and specificity (99.2%) for thrombus assessment compared with TEE [28]. Multiple studies have shown that the identification of presence of LA fibrosis on late gadolinium enhancement imaging is an independent predictor of postablation arrhythmia recurrence [33- 36]. This has led to the investigation of LA substrate-based ablation, in which these atrial fibrotic lesions are targeted in addition to the pulmonary veins to curb recurrence rates [37]. The prospective, multicenter Efficacy of Delayed Enhancement MRI-Guided Ablation vs Conventional Catheter Ablation of Atrial Fibrillation (DECAAF II) trial showed that among patients with persistent AF, MRI-guided fibrosis ablation plus pulmonary vein isolation, compared with pulmonary vein isolation catheter ablation only, resulted in no significant difference in atrial arrhythmia recurrence [6]. Other LA parameters such as LA volume, sphericity, LA volume index, LA emptying function, peak strain, and LA T1 relaxation time have also been assessed with MRI heart [32].


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. MRI Heart Function and Morphology Without IV Contrast MRI heart without IV contrast can provide cardiac function and chamber sizes, but the role in preprocedural planning is limited and there is scant literature on this topic. Also, unlike contrast-enhanced MRI heart, it is not sensitive for thrombus and cannot be used for scar assessment.


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. SPECT or SPECT/CT MPI Rest and Stress There is no relevant literature to support the use of single-photon emission computed tomography (SPECT) or SPECT/CT myocardial perfusion imaging (MPI) rest and stress for to guide preprocedural planning before LA ablation. However, many operators use isoproterenol infusions to assess the presence of nonpulmonary vein triggers. Prior to using high doses of isoproterenol, assessment of MPI may be advisable in patients with symptoms consistent with angina or those with limited functional capacity.


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. US Echocardiography Transesophageal TEE is a useful imaging technique for LA/LAA thrombus detection [38-40] and has a sensitivity of 93.3% to 100% and a specificity of 99% to 100%.


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. TEE cannot reliably assess pulmonary venous anatomy, pulmonary venous measurements, and extracardiac anatomic relations. Hence, alternative imaging techniques like CT and MR are being assessed to allow a more targeted use of TEE in patients with suspected thrombus.


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. US Echocardiography Transthoracic Resting Although TTE is commonly used in the initial workup of patients with AF and parameters such as LA volume/volume index, left ventricular ejection fraction [41], and LA size [42] can be assessed, there is no relevant literature that describes the specific use of TTE to guide preprocedural planning before LA ablation procedure.


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. Left Atrial Procedures in Atrial Fibrillation Variant 2: Adult. Atrial fibrillation. Preprocedural planning prior to left atrial appendage endovascular occlusion. Arteriography Coronary There is no relevant literature to support the use of routine coronary arteriography to guide preprocedural planning before LAA occlusion planning.


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. Catheter Venography Pulmonary There is no relevant literature to support the use of catheter pulmonary venography to guide preprocedural planning before LAA occlusion.


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. CT Chest With IV Contrast There is no relevant literature to support the use of CT chest with IV contrast to guide preprocedural planning before LAA occlusion.


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. CT Chest Without and With IV Contrast There is no relevant literature to support the use of CT chest without and with IV contrast to guide preprocedural planning before LAA occlusion.


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. CT Chest Without IV Contrast There is no relevant literature to support the use of CT chest without IV contrast to guide preprocedural planning before LAA occlusion.


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. An important role of CT is excluding contraindications to endovascular LAA occlusion procedures such as presence of thrombi. In a meta-analysis comparing CT and TEE for thrombus assessment, CT had a sensitivity and specificity of 96% and 92%, which increased to 100% and 99% if delayed imaging was performed [48].


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. CTA Chest With IV Contrast CTA of the chest can allow for assessment of the left atrium and LAA and can be performed with various acquisition parameters (with or without ECG gating) depending on scanner and local protocols. For device sizing, ECG-gated CTA is useful, and studies have shown high accuracy for gated CTA as outlined in the preceding section on CT heart [43,49].


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. Depending on the exact parameters, CTA chest with IV contrast is also useful in excluding thrombi especially when combined with delayed imaging. When coupled with delayed phase it has a 100% sensitivity [48].


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. CTA Coronary Arteries With IV Contrast There is no relevant literature to support the routine use of CTA coronary arteries with IV contrast to guide preprocedural planning before LAA occlusion procedures.


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. MRA Chest Without and With IV Contrast MRA chest with contrast can assess LA and LAA size and patency and identify LA/LAA thrombi with an accuracy of 94.3%, a sensitivity of 66.7%, and a specificity of 95.2% compared with TEE [28]. However, there are no large studies evaluating the use of MRA chest without and with IV contrast to guide preprocedural planning before LAA occlusion.


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. Left Atrial Procedures in Atrial Fibrillation MRA Chest Without IV Contrast There is no relevant literature to support the use of MRA chest without IV contrast to guide preprocedural planning for LAA occlusion procedures.


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. MRA Coronary Arteries Without and With IV Contrast There is no relevant literature to support the use of MRA coronary arteries without and with IV contrast to guide preprocedural planning for LAA occlusion procedures.


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. MRA Coronary Arteries Without IV Contrast There is no relevant literature to support the use of MRA coronary arteries without IV contrast to guide preprocedural planning for LAA occlusion procedures.


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. MRI Heart Function and Morphology Without and With IV Contrast MRI heart can assess the patency of the left atrium and LAA. There is a small amount of data assessing contrast- enhanced CMR for detection of LA/LAA thrombus. A retrospective analysis of 97 patients showed 100% concordance in LAA thrombus detection between 3-D early postgadolinium enhancement CMR and TEE [50]. Another study comparing CMR with TEE in 261 patients showed a 99.2% diagnostic accuracy for long T1 delayed enhancement CMR in detecting LAA thrombi [28]. This diagnostic accuracy was not affected by the presence of arrythmia during image acquisition. For the measurement of LAA, it needs to be complemented with a simultaneous 3D acquisition (ie, MRA). There are; however, no large studies to support the use of MRI in quantifying LAA size and morphology before endovascular occlusion [7]. A limitation of CMR is its lower spatial resolution and longer acquisition times when compared with CT.


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. MRI Heart Function and Morphology Without IV Contrast MRI heart without IV contrast can assess the size of left atrium. There is scant data in the literature supporting the use of noncontrast CMR for detecting LAA thrombi. Kitkungvan et al [28] compared CMR with TEE for detecting LAA thrombi. Steady-state free-precession (SSFP) cine MRI had a 91.6% diagnostic accuracy, 66.7% sensitivity, and 92.5% specificity.


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. There is no relevant literature to support the use of nonenhanced CMR in quantifying LAA size and morphology to guide preprocedural planning for LAA occlusion procedures.


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. SPECT or SPECT/CT MPI Rest and Stress There is no relevant literature to support the use of SPECT or SPECT/CT MPI rest and stress to guide preprocedural planning for LAA endovascular occlusion procedures.


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. US Echocardiography Transthoracic Resting Transthoracic echocardiography TTE assesses LA parameters that can help with patient risk stratification for thromboembolic events such as LA volume/volume index, left ventricular ejection fraction [41], and LA size [42]. However, there is no relevant literature to support the use of TTE specifically for preprocedural planning to guide LAA endovascular occlusion.


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. Variant 3: Adult. Atrial fibrillation. Preprocedural planning prior to electrical or pharmacologic cardioversion. Arteriography Coronary There is no relevant literature to support the use of coronary arteriography to guide preprocedural planning for cardioversion.


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. Catheter Venography Pulmonary There is no relevant literature to support the use of catheter pulmonary venography to guide preprocedural planning for cardioversion.


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. Left Atrial Procedures in Atrial Fibrillation CT Chest With IV Contrast CT chest can, in some cases, demonstrate thrombi; however, it is not optimized for LA assessment. There is no relevant literature to support the use of CT chest with IV contrast to guide preprocedural planning for cardioversion.


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. CT Chest Without and With IV Contrast There is no relevant literature to support the use of CT chest without and with IV contrast to guide preprocedural planning for cardioversion.


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. CT Chest Without IV Contrast There is no relevant literature to support the use of CT chest without IV contrast to guide preprocedural planning for cardioversion.


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. CT Heart Function and Morphology With IV Contrast There is increasing use of CT to exclude thrombus before LA procedures, especially when CT is already being performed for measurements and mapping (ie, before ablation and appendage occlusion). However, there are no large studies assessing the role of CT before cardioversion. In terms of diagnostic accuracy, CT has shown good performance for this indication (exclusion of thrombus), with a meta-analysis showing CT to have a sensitivity and specificity of 96% and 92%, respectively, which increased to 100% and 99%, respectively, if delayed imaging was performed [48]. Other studies have shown similar results [18,19,25]. CT has the advantage of noninvasive nature with 3-D capability.


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. CTA Chest With IV Contrast Depending on the exact parameters, CTA with IV contrast is useful in excluding thrombi especially when combined with delayed imaging. When coupled with delayed phase it has a 100% sensitivity and NPV [48].


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. CTA Coronary Arteries With IV Contrast There is no relevant literature to support the use of CTA coronary arteries with IV contrast to guide preprocedural planning for cardioversion.


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. MRA Chest Without and With IV Contrast MRA with IV contrast can identify LA/LAA thrombi with an accuracy of 94.3%, a sensitivity of 66.7%, and a specificity of 95.2% compared with TEE [28]. However, there are no large studies or relevant literature specifically evaluating the use of MRA chest without and with IV contrast for preprocedural planning before cardioversion.


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. MRA Chest Without IV Contrast There is no relevant literature to support the use of MRA chest without IV contrast to guide preprocedural planning for cardioversion.


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. MRA Coronary Arteries Without and With IV Contrast There is no relevant literature to support the use of MRA coronary arteries without and with IV contrast to guide preprocedural planning for cardioversion.


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. MRA Coronary Arteries Without IV Contrast There is no relevant literature to support the use of MRA coronary arteries without IV contrast to guide preprocedural planning for cardioversion.


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. MRI Heart Function and Morphology Without and With IV Contrast There is emerging data that contrast-enhanced CMR is a reliable imaging modality for the detection of LA/LAA thrombus. A retrospective analysis of 97 patients showed 100% concordance in LAA thrombus detection between 3-D early postgadolinium enhancement CMR and TEE [50]. Another study comparing CMR with TEE in 261 patients showed a 99.2% diagnostic accuracy for long T1 delayed enhancement CMR in detecting LAA thrombi [28].


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. MRI Heart Function and Morphology Without IV Contrast There is limited data in the literature supporting the use of noncontrast CMR for detecting LAA thrombi. Kitkungvan et al [28] compared CMR with TEE for detecting LAA thrombi. SSFP cine MRI had a 91.6% diagnostic accuracy, a 66.7% sensitivity, and a 92.5% specificity. Flow-related breathing and inhomogeneity artifacts were the main causes for this lower yield.


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. Left Atrial Procedures in Atrial Fibrillation SPECT or SPECT/CT MPI Rest and Stress There is no relevant literature to support the use of SPECT or SPECT/CT MPI rest and stress to guide preprocedural planning for cardioversion.


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. US Echocardiography Transesophageal TEE can assess for LA and LAA thrombus detection with a reported 97% sensitivity and 100% specificity [38]. TEE is useful as an alternative to periprocedural anticoagulation in patients with AF of unclear onset and duration or when AF duration is >48 hours, and in patients with known thrombosis, repeat TEE is suggested after 3 to 4 weeks of anticoagulation before cardioversion by the European Society of Cardiology [51].


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. 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.


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. For additional information on the Appropriateness Criteria methodology and other supporting documents go to www.acr.org/ac.


Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. Left Atrial Procedures in Atrial Fibrillation


Nonvariceal Upper Gastrointestinal Bleeding. Introduction/Background Upper gastrointestinal (GI) bleeding (UGIB) refers to bleeding occurring proximal to the ligament of Treitz, from the esophagus, stomach, or duodenum [1,2]. The incidence of nonvariceal UGIB is almost 5 times higher than that of variceal UGIB [1]. Peptic ulcer disease caused by Helicobacter pylori infection or nonsteroidal anti-inflammatory drug use is the most common cause of nonvariceal UGIB. The other causes of nonvariceal UGIB include Mallory- Weiss tears, esophagitis, pancreatitis, trauma, iatrogenic, or neoplastic [1]. Some rare causes of nonvariceal UGIB include hemobilia, hemosuccus pancreaticus, and aortoenteric fistula [3,4]. UGIB frequently presents with hematemesis or melena. However, a minority of patients can present with hematochezia [2]. GI bleeding (GIB) is either overt or occult. Patients with overt GIB present with signs of visible bleeding such as hematemesis, hematochezia, or melena. Patients with occult GIB have guaiac-positive stools or iron deficiency anemia, without visible blood loss. Obscure GIB refers to bleeding with unknown source despite complete GI tract imaging and endoscopic evaluation [2,5]. Clinically, obscure GIB can be overt (manifests as continued passage of visible blood) or occult (no visible blood).


Nonvariceal Upper Gastrointestinal Bleeding. Special Imaging Considerations Multiphase CT is used in the evaluation of patients with overt GIB, including noncontrast, late arterial, and venous phases of contrast administration [5]. With dual-energy CT, virtual noncontrast images can replace a true noncontrast acquisition [11]. Because the virtual noncontrast images are derived from the contrast-enhanced data set, these images are perfectly aligned, which can aid interpretation. The conspicuity of active GIB can also be increased by the use of low-keV virtual monoenergetic or iodine-only images [12]. In a study on the use of dual- energy CT imaging for patients presenting with clinical overt GIB, dual-energy CT images improved the radiologist


Nonvariceal Upper Gastrointestinal Bleeding. aUniversity of Wisconsin School of Medicine and Public Health, Madison, Wisconsin. bNYU Grossman School of Medicine, New York, New York. cPanel Chair, Brigham & Women's Hospital, Boston, Massachusetts. dPanel Chair, University of California San Diego, San Diego, California. ePanel Vice-Chair, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts. fGlobal Advanced Imaging, PLLC, Little Rock, Arkansas; Commission on Nuclear Medicine and Molecular Imaging. gUniversity of Texas Health Science Center at Houston and McGovern Medical School, Houston, Texas; American Gastroenterological Association. hMayo Clinic, Rochester, Minnesota; Society for Cardiovascular Magnetic Resonance. iOchsner Hospital, Baton Rouge, Louisiana. jUMass Memorial Health and UMass Chan Medical School, Worcester, Massachusetts; Committee on Emergency Radiology- GSER. kUniversity of North Carolina at Chapel Hill, Chapel Hill, North Carolina. lVA Puget Sound Health Care System and University of Washington, Seattle, Washington. mUniversity of California San Diego, San Diego, California. nSpecialty Chair, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin. oSpecialty Chair, Brigham & Women's Hospital, Boston, Massachusetts.


Nonvariceal Upper Gastrointestinal Bleeding. Reprint requests to: publications@acr.org


Nonvariceal Upper Gastrointestinal Bleeding. Nonvariceal Upper Gastrointestinal Bleeding confidence in appropriate diagnosis, especially in patients without findings of bleeding on CT [12]. Additionally, low-keV images can be used to reduce the volume of intravenous (IV) contrast used. However, the use of these virtual unenhanced images in place of true unenhanced images is still limited to certain sites and remains a user- specific preference [5]. Hence, considerations specific to virtual noncontrast images are not discussed in this document.


Nonvariceal Upper Gastrointestinal Bleeding. 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.


Nonvariceal Upper Gastrointestinal Bleeding. OR Discussion of Procedures by Variant Variant 1: Adult. Suspected nonvariceal upper gastrointestinal bleeding; no endoscopy performed. Initial imaging. Endoscopy is the usual first test in patients presenting with overt or occult UGIB [6]. This variant is applicable to a clinical scenario in which a patient presents clinically with overt UGIB and initial endoscopy was not performed due to large volume bleeding or clinical instability.


Nonvariceal Upper Gastrointestinal Bleeding. CT Abdomen and Pelvis With IV Contrast There is no significant literature supporting the use of CT abdomen and pelvis with IV contrast. (Note: CTA is a separate procedure distinct from CT abdomen and pelvis with IV contrast.)


Nonvariceal Upper Gastrointestinal Bleeding. CT Abdomen and Pelvis Without and With IV Contrast There is no significant literature supporting the use of CT abdomen and pelvis without and with IV contrast. (Note: CTA is a separate procedure distinct from CT abdomen and pelvis with IV contrast.)


Nonvariceal Upper Gastrointestinal Bleeding. Nonvariceal Upper Gastrointestinal Bleeding CT Abdomen and Pelvis Without IV Contrast There is no significant literature supporting the use of CT abdomen and pelvis without IV contrast. (Note: CTA is a separate procedure distinct from CT abdomen and pelvis with IV contrast.)


Nonvariceal Upper Gastrointestinal Bleeding. CT Abdomen With IV Contrast There is no significant literature supporting the use of CT abdomen with IV contrast. (Note: CTA is a separate procedure distinct from CT abdomen and pelvis with IV contrast.)


Nonvariceal Upper Gastrointestinal Bleeding. CT Abdomen Without and With IV Contrast There is no significant literature supporting the use of CT abdomen without and with IV contrast. (Note: CTA is a separate procedure distinct from CT abdomen and pelvis with IV contrast.)


Nonvariceal Upper Gastrointestinal Bleeding. CT Abdomen Without IV Contrast There is no significant literature supporting the use of CT abdomen without IV contrast. (Note: CTA is a separate procedure distinct from CT abdomen and pelvis with IV contrast.)


Nonvariceal Upper Gastrointestinal Bleeding. CT Enterography There is no significant literature supporting the use of CT enterography in patients with overt UGIB. CT enterography requires the administration of large volumes of neutral oral contrast, which can mask GIB by dilution. Additionally, a large volume of oral contrast is often not tolerated by acutely ill patients. CT enterography is recommended by the Society of Abdominal Radiology Gastrointestinal Bleeding Disease-Focused Panel for patients with occult GIB or suspected small bowel bleeding, which often uses a multiphase technique [5].


Nonvariceal Upper Gastrointestinal Bleeding. CTA Abdomen and Pelvis With IV Contrast There is no significant literature supporting the use of CTA abdomen and pelvis with IV contrast only. The literature primarily reflects studies with CTA examinations without and with IV contrast. Dual-energy CT allows for the generation of virtual noncontrast images from a CTA data set. However, the use of these virtual unenhanced images in place of true unenhanced images is still limited to certain sites and remains a user-specific preference. So, they are not discussed in this document.


Nonvariceal Upper Gastrointestinal Bleeding. CTA Abdomen and Pelvis Without and With IV Contrast CTA without and with IV contrast can help with the detection of a source for GIB [7,18]. CTA has been shown to be able to detect bleeding rates as slow as 0.3 mL/min, compared with 0.5 to 1.0 mL/min for conventional angiography and 0.2 mL/min for Tc-99m-labeled red blood cell (RBC) scintigraphy [19]. Faster acquisition, thin collimation, and greater availability have led to greater utilization of this study. The noncontrast images are useful for the detection of intraluminal high-attenuation material that may mimic intraluminal blood on contrast-enhanced images and may be necessary for the identification of sentinel clot [7]. The Society of Abdominal Radiology Gastrointestinal Bleeding Disease-Focused Panel published a consensus on CT imaging protocols for the detection of overt GIB [20]. With a 100% consensus, the experts recommended noncontrast images for CTA performed on single-energy CT. This can be replaced by virtual noncontrast reconstructions with dual-energy CT [20,21]. In a meta-analysis of 22 studies evaluating accuracy of CTA for the diagnosis of active GIB (total of 672 patients), CTA had a sensitivity and specificity of 85% and 92%, respectively. Frequently, multiphase acquisition is performed, with a portal venous or a delayed phase (typically acquired during 70-90 sec window after the initiation of the contrast bolus injection) in addition to the angiographic phase [7,20]. In a study evaluating different CT imaging protocols, multiphasic CT protocols (unenhanced + arterial + portal venous phase) had the highest sensitivity of 92% for the detection of GIB compared with 83% for unenhanced phase with arterial or portal venous phase alone [18]. Oral contrast is usually not given for GIB studies because a positive oral contrast will render the examination nondiagnostic, and oral water can dilute intraluminal hemorrhage [7]. In an 8-year follow-up study after initial negative CT for suspected GIB, nearly 60% of patients with suspected UGIB, and nearly 77% patients with suspected lower GIB did not rebleed, suggesting relatively higher odds of rebleeding for UGIB compared with lower GIB despite a negative CTA [22]. In a retrospective study among patients with positive CTA for GIB, greater contrast extravasation volume on CT was significantly correlated with use of hemostatic therapy, intraprocedural active bleeding, and massive transfusion. The extravasation volume, however, did not correlate with patient mortality [23]. CTA may still be underused for the diagnosis of GIB [24]. Compared with Tc-99m-labeled RBC scintigraphy, CTA can lead to faster triage of patients toward definitive treatment by angiography [25]. Likewise, the use of CTA as the first test leads to faster triage of patients in the emergency room when compared with endoscopy for GI bleed [24].


Nonvariceal Upper Gastrointestinal Bleeding. Nonvariceal Upper Gastrointestinal Bleeding CTA Abdomen With IV Contrast Although CTA can detect GIB, typically both the abdomen and pelvis are imaged, because the site of bleeding is unclear without endoscopy. There is no significant literature supporting the use of CTA abdomen with IV contrast only.


Nonvariceal Upper Gastrointestinal Bleeding. CTA Abdomen Without and With IV Contrast Although CTA can detect GIB, typically both the abdomen and pelvis are imaged, because the site of bleeding is unclear without endoscopy. There is no significant literature supporting the use of CTA abdomen without and with IV contrast only.


Nonvariceal Upper Gastrointestinal Bleeding. CTA Chest With IV Contrast Although esophageal bleed (which can be localized on CTA chest) can present as UGIB, the literature supports CTA of abdomen and pelvis if the site of bleeding is unclear without endoscopy. There is no significant literature supporting the use of CTA chest with IV contrast.


Nonvariceal Upper Gastrointestinal Bleeding. CTA Chest Without and With IV Contrast Although esophageal bleed (which can be localized to CTA chest) can present as UGIB, the literature supports CTA of abdomen and pelvis without and with IV contrast, if the site of bleeding is unclear without endoscopy. There is no significant literature supporting the use of CTA chest without and with IV contrast.


Nonvariceal Upper Gastrointestinal Bleeding. Fluoroscopy Upper GI Series Barium or iodine upper GI series has no role in the diagnosis of acute UGIB in a modern-day practice.


Nonvariceal Upper Gastrointestinal Bleeding. MR Enterography There is no significant literature supporting the use of MR enterography in patients with overt UGIB.


Nonvariceal Upper Gastrointestinal Bleeding. RBC Scan Abdomen and Pelvis There is no significant literature to support the use of a Tc-99m-labeled RBC scan of the abdomen and pelvis for the initial imaging of suspected overt UGIB (without endoscopy performed).


Nonvariceal Upper Gastrointestinal Bleeding. Variant 2: Adult. Endoscopy confirms nonvariceal upper gastrointestinal bleeding with a clear source, but treatment not possible or continued bleeding after endoscopic treatment. Initial imaging. This variant is applicable in a clinical scenario when the patient had endoscopy performed, which diagnosed the upper GI tract as the source of bleed, but definitive treatment of the bleeding was not possible or there is continued bleeding after treatment.


Nonvariceal Upper Gastrointestinal Bleeding. Arteriography Visceral There is an 88% to 100% success rate of VA for diagnosis of endoscopically refractory bleeding from the esophagus due to inflammatory or neoplastic pathology [26,27] or periesophageal pseudoaneurysm [28]. In a study among patients with postesophagectomy gastric conduit hemorrhage [29], VA identified the source of active bleeding in 85% of patients. In a study among patients with gastric cancer refractory to endoscopy, angiography could diagnose active bleeding in 22.4% (13/58) of patients [30]. In other studies in patients with bleeding GI tumors, VA showed active bleeding in 25% to 55% of patients [31,32]. Among patients with pancreatic cancer presenting with endoscopically refractory UGIB, angiography detected active bleeding in 81% of patients [33,34]. Although there is more literature on clinical success of angiographic embolization for treatment of gastric and duodenal ulcers refractory to endoscopic treatment [34-37], duodenal fistula [38], and iatrogenic bleeding following laparoscopic cholecystectomy or endoscopic pancreaticobiliary drainage [4,39,40], the literature on diagnostic accuracy for bleeding is limited in these studies.


Nonvariceal Upper Gastrointestinal Bleeding. CT Abdomen and Pelvis With IV Contrast There is no significant literature supporting the use of CT abdomen and pelvis with IV contrast. (Note: CTA is a separate procedure distinct from CT abdomen and pelvis with IV contrast).


Nonvariceal Upper Gastrointestinal Bleeding. CT Abdomen and Pelvis Without and With IV Contrast There is no significant literature supporting the use of CT abdomen and pelvis without and with IV contrast. (Note: CTA is a separate procedure distinct from CT abdomen and pelvis without and with IV contrast).


Nonvariceal Upper Gastrointestinal Bleeding. CT Abdomen and Pelvis Without IV Contrast There is no significant literature supporting the use of CT abdomen and pelvis without IV contrast. (Note: CTA is a separate procedure distinct from CT abdomen and pelvis without IV contrast).


Nonvariceal Upper Gastrointestinal Bleeding. Nonvariceal Upper Gastrointestinal Bleeding CT Abdomen With IV Contrast There is no significant literature supporting the use of CT abdomen with IV contrast. (Note: CTA is a separate procedure distinct from CT abdomen with IV contrast).


Nonvariceal Upper Gastrointestinal Bleeding. CT Abdomen Without and With IV Contrast There is no significant literature supporting the use of CT abdomen without and with IV contrast. (Note: CTA is a separate procedure distinct from CT abdomen without and with IV contrast).


Nonvariceal Upper Gastrointestinal Bleeding. CT Abdomen Without IV Contrast There is no significant literature supporting the use of CT abdomen without IV contrast. (Note: CTA is a separate procedure distinct from CT abdomen without IV contrast).


Nonvariceal Upper Gastrointestinal Bleeding. CT Enterography There is no significant literature supporting the use of CT enterography as an imaging test for overt UGIB, which is untreatable by endoscopy. Although multiphasic CT enterography can detect bleeding because of technique parameters that can mirror CTA, the primary use of this protocol is directed more at finding a potential bleeding source when bleeding is of a slow rate [41] in patients with occult GI or suspected small bowel bleeding [5].


Nonvariceal Upper Gastrointestinal Bleeding. CTA Abdomen and Pelvis With IV Contrast Although CTA can detect overt GIB, performance with IV contrast only may not be as helpful. There is no significant literature supporting the use of CTA abdomen and pelvis with IV contrast. Noncontrast images can aid in the identification of a sentinel clot. Dual-energy CT allows for the generation of virtual noncontrast images from a CTA data set. However, the use of these virtual unenhanced images in place of true unenhanced images is still limited to certain sites and remains a user-specific preference. So, they are not discussed in this document.


Nonvariceal Upper Gastrointestinal Bleeding. CTA Abdomen and Pelvis Without and With IV Contrast Although there is no literature to discuss the difference between diagnostic accuracy of CTA abdomen and pelvis without and with IV contrast versus CTA abdomen without and with IV contrast or CTA chest without and with IV contrast, in patients with a known source of bleeding that cannot be controlled endoscopically, the imaging should be tailored to include the site of the bleeding. Overall, CTA has good accuracy for the detection of tumor bleeding, vascular malformations, or diverticular bleeding [7,42,43].


Nonvariceal Upper Gastrointestinal Bleeding. CTA Abdomen With IV Contrast There is no significant literature supporting the use of CTA abdomen with IV contrast.


Nonvariceal Upper Gastrointestinal Bleeding. CTA Abdomen Without and With IV Contrast There is no significant literature comparing the use of CTA abdomen and pelvis without and with IV contrast for UGIB. However, as highlighted earlier in this document, if the known source of bleeding if localized to abdomen, this test may be helpful. CTA pelvis may be ordered simultaneously; however, the primary role would be for vascular access mapping.


Nonvariceal Upper Gastrointestinal Bleeding. CTA Chest With IV Contrast There is no significant literature supporting the use of CTA chest with IV contrast.


Nonvariceal Upper Gastrointestinal Bleeding. CTA Chest Without and With IV Contrast There is no significant literature comparing the use of CTA chest without and with IV contrast for UGIB. However, as highlighted earlier in this document, if the known source of bleeding is localized to the chest, this test may be helpful.


Nonvariceal Upper Gastrointestinal Bleeding. Fluoroscopy Upper GI Series Barium or iodine upper GI series has no role in the diagnosis of acute UGIB.


Nonvariceal Upper Gastrointestinal Bleeding. MR Enterography There is no significant literature supporting the use of MR enterography as an imaging test for overt UGIB, which is untreatable by endoscopy.


Nonvariceal Upper Gastrointestinal Bleeding. RBC Scan Abdomen and Pelvis There is no significant literature to support the use of a Tc-99m-labeled RBC scan of the abdomen and pelvis for the diagnosis of GIB when the source of bleeding is obvious but unmanageable on endoscopy.


Nonvariceal Upper Gastrointestinal Bleeding. Nonvariceal Upper Gastrointestinal Bleeding Variant 3: Adult. Endoscopy confirms nonvariceal upper gastrointestinal bleeding without a clear source. Initial imaging. This variant is applicable to clinical scenario in which endoscopy shows UGIB but the site or source of the bleeding cannot be determined on endoscopy. Clinically, these patients typically present with overt GIB.


Nonvariceal Upper Gastrointestinal Bleeding. Arteriography Visceral VA can be attempted in such cases; however, it also has the limitation that if the bleeding is not active, it may not be seen. VA has the advantage of assessing the entire mesenteric circulation. Provocation techniques including intraprocedure heparin administration, intra-arterial nitroglycerin administration, and low-dose tissue plasminogen activator administration have been shown to increase the sensitivity of VA for the detection of GIB [44]. However, the literature on safety of these maneuvers and the effect on patient outcomes is limited. The other methods described in the literature that can enhance detection of bleeding on VA are glucagon and hyoscine butylbromide administration (to decrease bowel motility and artifacts), the use of carbon dioxide as a contrast medium, and longer injection durations [45]. Limitations include its invasive nature and higher bleeding rate threshold to diagnose obscure bleeding [46].


Nonvariceal Upper Gastrointestinal Bleeding. CT Abdomen and Pelvis With IV Contrast There is no significant literature supporting the use of CT abdomen and pelvis with IV contrast. (Note: CTA is a separate procedure distinct from CT abdomen and pelvis with IV contrast).


Nonvariceal Upper Gastrointestinal Bleeding. CT Abdomen and Pelvis Without and With IV Contrast There is no significant literature supporting the use of CT abdomen and pelvis without and with IV contrast. (Note: CTA is a separate procedure distinct from CT abdomen and pelvis without and with IV contrast).


Nonvariceal Upper Gastrointestinal Bleeding. CT Abdomen and Pelvis Without IV Contrast There is no significant literature supporting the use of CT abdomen and pelvis without IV contrast. (Note: CTA is a separate procedure distinct from CT abdomen and pelvis without IV contrast).


Nonvariceal Upper Gastrointestinal Bleeding. CT Abdomen With IV Contrast There is no significant literature supporting the use of CT abdomen with IV contrast. (Note: CTA is a separate procedure distinct from CT abdomen with IV contrast).


Nonvariceal Upper Gastrointestinal Bleeding. CT Abdomen Without and With IV Contrast There is no significant literature supporting the use of CT abdomen without and with IV contrast. (Note: CTA is a separate procedure distinct from CT abdomen without and with IV contrast).


Nonvariceal Upper Gastrointestinal Bleeding. CT Abdomen Without IV Contrast There is no significant literature supporting the use of CT abdomen without IV contrast. (Note: CTA is a separate procedure distinct from CT abdomen without IV contrast).


Nonvariceal Upper Gastrointestinal Bleeding. CT Enterography CT enterography requires the administration of large volumes of neutral oral contrast, which can mask bleeding by dilution. Although multiphasic CT enterography can detect bleeding because of technique parameters that can mirror CTA, the primary use of this protocol is directed more to finding a potential bleeding source when bleeding is of a slow rate, suspected in the small bowel, or occult in nature [41].


Nonvariceal Upper Gastrointestinal Bleeding. CTA Abdomen and Pelvis With IV Contrast There is no significant literature supporting the use of CTA abdomen and pelvis with IV contrast. Dual-energy CT allows for the generation of virtual noncontrast images from a CTA data set. However, the use of these virtual unenhanced images in place of true unenhanced images is still limited to certain sites and remains a user-specific preference. So, they are not discussed in this document.


Nonvariceal Upper Gastrointestinal Bleeding. CTA Abdomen and Pelvis Without and With IV Contrast Besides angiography, CTA abdomen and pelvis without and with IV contrast may become useful when endoscopy shows nonvariceal UGIB without a clear source. As highlighted in previous variants, CTA without and with IV contrast has high accuracy for the detection of GIB. CTA can detect small bowel lesions that may be difficult to see on traditional esophagogastroduodenoscopy but may be better visualized by push enteroscopy [43]. Because CTA can identify a slower bleeding rate than angiography, CTA has been demonstrated to have significantly higher detection of active bleeding as well as localization of the culprit lesion [46]. CTA can also show Dieulafoy lesions that have a very high mortality rate [47,48].


Nonvariceal Upper Gastrointestinal Bleeding. Nonvariceal Upper Gastrointestinal Bleeding CTA Abdomen With IV Contrast There is no significant literature supporting the use of CTA abdomen with IV contrast.


Nonvariceal Upper Gastrointestinal Bleeding. CTA Abdomen Without and With IV Contrast There is no significant literature supporting the use of CTA abdomen without and with IV contrast, because lesions not clearly seen on endoscopy may be localized to small bowel, which often requires inclusion of the pelvis.


Nonvariceal Upper Gastrointestinal Bleeding. CTA Chest With IV Contrast There is no significant literature supporting the use of CTA chest with IV contrast.


Nonvariceal Upper Gastrointestinal Bleeding. CTA Chest Without and With IV Contrast There is no significant literature supporting the use of CTA chest without and with IV contrast.


Nonvariceal Upper Gastrointestinal Bleeding. Fluoroscopy Upper GI Series Barium or iodine upper GI series has no role in the diagnosis of acute UGIB.


Nonvariceal Upper Gastrointestinal Bleeding. MR Enterography There is no significant literature supporting the use of MR enterography as an imaging test for UGIB, which is confirmed on endoscopy but without a clear source.


Nonvariceal Upper Gastrointestinal Bleeding. RBC Scan Abdomen and Pelvis Because CTA evaluation is a well-recognized next step in the management of UGIB if endoscopy confirms bleeding without identification of a source, there is no significant literature outlining the use of nuclear medicine studies in this clinical context. However, Tc-99m-labeled RBC scanning can be used to localize a low-rate source of bleeding.


Nonvariceal Upper Gastrointestinal Bleeding. Variant 4: Adult. Nonvariceal upper gastrointestinal bleeding; negative endoscopy. Initial imaging. This variant is applicable to patients with no clear source of bleeding despite complete endoscopic evaluation. Clinically, these patients can have obscure bleeding (which may be noted in the form of visible passage of blood or melena or occult bleeding, unexplained iron deficiency anemia, or guaiac-positive stools without visible passage of blood). Small bowel pathology is the frequent source of bleeding in these patients.


Nonvariceal Upper Gastrointestinal Bleeding. Arteriography Visceral VA, due to a lower sensitivity for the detection of bleeding and its invasive nature, is considered lower on the diagnostic algorithm compared with more sensitive noninvasive testing [49,50]. Super-selective angiography with intraoperative methylene blue localization may help to diagnose and effectively control bleeding in patients with obscure GIB [51]. In patients with negative endoscopy, VA has false-negative results, because the bleeding is typically detected when the rate is at least 0.5 mL/min. It has been shown that there is no benefit of performing angiography in patients with occult GIB who have a negative CTA study [50].


Nonvariceal Upper Gastrointestinal Bleeding. CT Abdomen and Pelvis With IV Contrast In endoscopy-negative patients, there is no significant literature for CT abdomen and pelvis with IV contrast for GIB evaluation. However, CT may be performed primarily for the evaluation of GI masses rather than the demonstration of bleeding. (Note: CTA is a separate procedure distinct from CT abdomen and pelvis with IV contrast).


Nonvariceal Upper Gastrointestinal Bleeding. CT Abdomen and Pelvis Without and With IV Contrast In endoscopy-negative patients, there is no significant literature for CT abdomen and pelvis without and with IV contrast for GIB evaluation. Although there is not enough literature supporting its use, the test may serve as an initial test for patients with obscure or occult bleeding, especially if an alternative is needed for CTA or enterography. (Note: CTA is a separate procedure distinct from CT abdomen and pelvis without and with IV contrast).


Nonvariceal Upper Gastrointestinal Bleeding. CT Abdomen and Pelvis Without IV Contrast In endoscopy-negative patients, there is no significant literature for CT abdomen and pelvis without IV contrast for GIB evaluation. (Note: CTA is a separate procedure distinct from CT abdomen and pelvis without IV contrast).


Nonvariceal Upper Gastrointestinal Bleeding. CT Abdomen With IV Contrast In endoscopy-negative patients, there is no significant literature for CT abdomen with IV contrast for GIB evaluation. (Note: CTA is a separate procedure distinct from CT abdomen with IV contrast).


Nonvariceal Upper Gastrointestinal Bleeding. Nonvariceal Upper Gastrointestinal Bleeding CT Abdomen Without and With IV Contrast In endoscopy-negative patients, there is no significant literature for CT abdomen without and with IV contrast for GIB evaluation. (Note: CTA is a separate procedure distinct from CT abdomen without and with IV contrast).


Nonvariceal Upper Gastrointestinal Bleeding. CT Abdomen Without IV Contrast In endoscopy-negative patients, there is no significant literature for CT abdomen without IV contrast for GIB evaluation. (Note: CTA is a separate procedure distinct from CT abdomen without IV contrast).


Nonvariceal Upper Gastrointestinal Bleeding. CT Enterography Although CT enterography is not considered useful for detection of acute bleeding due to the dilution of bleeding from oral contrast, it may be helpful in patients with negative endoscopy to identify a small bowel source of GIB. The sensitivity for detection of the cause of occult GIB is typically low, with measured sensitivity of 25% compared with capsule endoscopy (sensitivity of 87%) and 33% when compared with clinical follow-up in patients with nondiagnostic capsule endoscopy [52,53]. However, a study showed a higher sensitivity of CT enterography (88%) for the diagnosis of etiology of occult GIB, significantly higher than capsule endoscopy (sensitivity 38%) in their study population [54]. Advantages of CT enterography over capsule endoscopy are ease of performance and better patient satisfaction [5].


Nonvariceal Upper Gastrointestinal Bleeding. CTA Abdomen and Pelvis With IV Contrast In endoscopy-negative patients, there is no significant literature for CT abdomen and pelvis with IV contrast for GIB evaluation. Dual-energy CT allows for the generation of virtual noncontrast images from a CTA data set. However, the use of these virtual unenhanced images in place of true unenhanced images is still limited to certain sites and remains a user-specific preference. So, they are not discussed in this document.


Nonvariceal Upper Gastrointestinal Bleeding. CTA Abdomen and Pelvis Without and With IV Contrast Both CTA and CT enterography are effective imaging tests for the diagnosis of UGIB with negative endoscopy. Studies have demonstrated that there is no significant clinical difference between accuracy of CTA and enterography for endoscopy-negative GIB [55,56]. CTA can detect bleeding rates as slow as 0.3 mL/min [19]. But, as with angiography, intermittent and slow bleeding can be missed, leading to false-negatives. The sensitivity of CTA has been shown to be 81% in high-risk patients (ie, patients requiring 500 mL of transfusion to maintain vital signs), which decreases to 50% in patients with a slow bleed [57]. The portal venous or delayed phase of multiphasic CT may be more useful for detection of GI masses. CTA and CT enterography can serve as triage tools for identifying patients who may benefit from double-balloon endoscopy [58].


Nonvariceal Upper Gastrointestinal Bleeding. CTA Abdomen With IV Contrast In endoscopy-negative patients, there is no significant literature for CTA abdomen with IV contrast for GIB evaluation.


Nonvariceal Upper Gastrointestinal Bleeding. CTA Abdomen Without and With IV Contrast In endoscopy-negative patients, there is no significant literature for CTA abdomen without and with IV contrast for GIB evaluation. Because the pathology can be located anywhere in the small bowel, it is more appropriate to image both the abdomen and pelvis.


Nonvariceal Upper Gastrointestinal Bleeding. CTA Chest With IV Contrast In endoscopy-negative patients, there is no significant literature for CTA chest with IV contrast for GIB evaluation.


Nonvariceal Upper Gastrointestinal Bleeding. CTA Chest Without and With IV Contrast In endoscopy-negative patients, there is no significant literature for CTA chest without and with IV contrast for GIB evaluation.


Nonvariceal Upper Gastrointestinal Bleeding. Fluoroscopy Upper GI Series Barium or iodine upper GI series has no role in diagnosis of acute UGIB.


Nonvariceal Upper Gastrointestinal Bleeding. MR Enterography Similar to CT enterography, MR enterography requires oral administration of oral contrast that can obscure bleeding. But MR enterography has been used to identify small bowel sources of bleeding in pediatric patients. In a study of 25 pediatric patients with occult GIB, MR enterography was shown to be diagnostic in 79% patients, with a sensitivity and specificity of 86% and 100%, respectively [59]. Few other studies have also compared capsule with MR enterography and demonstrated better diagnostic yields for capsule endoscopy [60,61]. However, there is


Nonvariceal Upper Gastrointestinal Bleeding. Nonvariceal Upper Gastrointestinal Bleeding not enough direct evidence to suggest that MR enterography has an advantage over CT enterography or capsule endoscopy in patients with UGIB and negative endoscopy, particularly in adults.


Nonvariceal Upper Gastrointestinal Bleeding. RBC Scan Abdomen and Pelvis Tc-99m-labeled RBC scans can detect bleeding rates as low as 0.05 to 0.1 mL/min. Although there is prior literature on the use of RBC abdomen and pelvis scan, no recent studies have compared the accuracy of RBC scan to CTA or angiography for occult UGIB. Prior reports had suggested variable efficacy for the diagnosis of GIB with localization errors, especially when bleeding arises from the stomach and duodenum [62,63]. However, the use of single-photon emission CT (SPECT) and SPECT/CT have made the anatomical position of the uptake clear and contributed to the improved localization of the site of GIB [64].


Nonvariceal Upper Gastrointestinal Bleeding. Variant 5: Adult. Postsurgical or traumatic causes of nonvariceal upper gastrointestinal bleeding. Endoscopy is contraindicated. Initial imaging. This variant is applicable to postsurgical or trauma patients with UGIB, contraindicated to upper GI endoscopy.


Nonvariceal Upper Gastrointestinal Bleeding. Arteriography Visceral VA is primarily reserved for unstable patients with UGIB and contraindicated for endoscopy, because it can be used for diagnosis and simultaneous treatment [27,65]. Typically, unstable patients with traumatic hemobilia and bleeding after mucosal or submucosal endoscopic mass resection may require VA [4,39,65]. In stable patients, VA may be performed after CTA, which can show the site of bleeding or a pseudoaneurysm [4,39].


Nonvariceal Upper Gastrointestinal Bleeding. CT Abdomen and Pelvis With IV Contrast There is no significant literature supporting the use of CT abdomen and pelvis with IV contrast for postsurgical or post-traumatic UGIB. However, in general, CT of the abdomen and pelvis with IV contrast is routinely used in trauma patients to assess for intra-abdominal injury. In a meta-analysis of 16 studies enrolling 12,514 patients, CT of the abdomen and pelvis had a sensitivity and specificity of 68% and 97%, respectively, for the diagnosis of traumatic hollow viscus injury [66]. (Note: CTA is a separate procedure distinct from CT abdomen and pelvis with IV contrast).


Nonvariceal Upper Gastrointestinal Bleeding. CT Abdomen and Pelvis Without and With IV Contrast There is no significant literature supporting the use of CT abdomen and pelvis without and with IV contrast for postsurgical or post-traumatic UGIB. (Note: CTA is a separate procedure distinct from CT abdomen and pelvis without and with IV contrast).


Nonvariceal Upper Gastrointestinal Bleeding. CT Abdomen and Pelvis Without IV Contrast There is no significant literature supporting the use of CT abdomen and pelvis without IV contrast for postsurgical or post-traumatic UGIB. (Note: CTA is a separate procedure distinct from CT abdomen and pelvis without IV contrast).


Nonvariceal Upper Gastrointestinal Bleeding. CT Abdomen With IV Contrast There is no significant literature supporting the use of CT abdomen with IV contrast for postsurgical or post- traumatic UGIB. (Note: CTA is a separate procedure distinct from CT abdomen with IV contrast).


Nonvariceal Upper Gastrointestinal Bleeding. CT Abdomen Without and With IV Contrast There is no significant literature supporting the use of CT abdomen without and with IV contrast for postsurgical or post-traumatic UGIB. However, CT of the abdomen without and with IV contrast may be considered in patients who are suspected to have postsurgical UGIB or hemobilia [67]. In a study of postlaparoscopic sleeve gastrectomy patients presenting with UGIB, CT was able to diagnose all patients with surgical site pseudoaneurysm who were successfully treated by surgery or transcatheter arterial embolization [68]. The patients with poststent ulceration or mucosal diseases are, however, often undiagnosed by CT [68].


Nonvariceal Upper Gastrointestinal Bleeding. CT Abdomen Without IV Contrast There is no significant literature supporting the use of CT abdomen without IV contrast for postsurgical or post- traumatic UGIB.


Nonvariceal Upper Gastrointestinal Bleeding. CT Enterography There is no significant literature supporting the use of CT enterography for postsurgical or post-traumatic UGIB. CT enterography requires the administration of large volumes of neutral oral contrast, which can mask GIB by dilution. Additionally, a large volume of oral contrast is often not tolerated by patients when acutely ill. However,


Nonvariceal Upper Gastrointestinal Bleeding. Nonvariceal Upper Gastrointestinal Bleeding CT enterography can detect GIB because of technique parameters that can mirror CTA and is useful for patients with occult GI or suspected small bowel bleeding [5].


Nonvariceal Upper Gastrointestinal Bleeding. CTA Abdomen and Pelvis With IV Contrast Although CTA can detect arterial post-traumatic bleeding, performance with IV contrast only may not be as helpful. Without contrast images are important to identify sentinel clot and inherently hyperdense intraluminal material. Dual-energy CT allows for the generation of virtual noncontrast images from a CTA data set. However, the use of these virtual unenhanced images in place of true unenhanced images is still limited to certain sites and remains a user-specific preference. So, they are not discussed in this document. There is no significant literature supporting the use of CTA abdomen and pelvis with IV contrast only.


Nonvariceal Upper Gastrointestinal Bleeding. CTA Abdomen and Pelvis Without and With IV Contrast In traumatic UGIB, it is important to identify the source quickly, safely, and effectively. CT is frequently performed in patients with trauma to assess for visceral injuries. In patients with UGIB, multiphase CTA can effectively and quickly evaluate abdominal vasculature, GIB, and visceral injuries simultaneously. Mesenteric contrast extravasation has a 75% sensitivity for mesenteric injury [69]. CT can help in triage and prognostication, with active bleeding in the arterial or portal venous phase more likely to be life-threatening versus bleeding that first appears in the equilibrium phase [69]. A rare but life-threatening cause of postsurgical or iatrogenic UGIB can be aortoenteric fistula. CTA is the examination of choice [70]. Evidence of a fistula is suggested by gas in a periprosthetic fluid collection, retraction of the contacting intestinal walls, or the presence of a false aneurysm. Extravasation of contrast into the intestinal lumen is diagnostic of aortoenteric fistula but rarely occurs. Even in patients that can undergo endoscopy, CTA is superior and more sensitive compared with endoscopy for the diagnosis of aortoenteric fistula [71].


Nonvariceal Upper Gastrointestinal Bleeding. CTA Abdomen With IV Contrast There is no significant literature supporting the use of CTA abdomen with IV contrast for postsurgical or post- traumatic UGIB.


Nonvariceal Upper Gastrointestinal Bleeding. CTA Abdomen Without and With IV Contrast There is no significant literature supporting the use of CTA abdomen without and with IV contrast for postsurgical or post-traumatic UGIB.


Nonvariceal Upper Gastrointestinal Bleeding. CTA Chest With IV Contrast There is no significant literature supporting the use of CTA chest with IV contrast for postsurgical or post-traumatic UGIB.


Nonvariceal Upper Gastrointestinal Bleeding. CTA Chest Without and With IV Contrast There is no significant literature comparing the use of CTA chest without and with IV contrast for UGIB. However, as highlighted earlier in this document, if the trauma or prior surgery is localized to the chest, this test may be helpful.


Nonvariceal Upper Gastrointestinal Bleeding. Fluoroscopy Upper GI Series Barium or iodine upper GI series has no role in the diagnosis of acute UGIB.


Nonvariceal Upper Gastrointestinal Bleeding. RBC Scan Abdomen and Pelvis There is no significant literature outlining the use of Tc-99m-labeled RBC scanning when endoscopy is contraindicated.


Nonvariceal Upper Gastrointestinal Bleeding. Nonvariceal Upper Gastrointestinal Bleeding 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.


Nonvariceal Upper Gastrointestinal Bleeding. For additional information on the Appropriateness Criteria methodology and other supporting documents go to www.acr.org/ac.


Neuroendocrine Imaging

Neuroendocrine Imaging. Introduction/Background Neuroendocrine abnormalities encompass a range of centrally mediated hormonal imbalances and organ-specific pituitary abnormalities. Imaging is generally focused on the pituitary gland and parasellar region and typically follows endocrine evaluation [1-3]. Abnormalities of the pituitary are often an incidental finding on imaging performed for other indications, though these may be associated with occult endocrine dysfunction [4], and focused imaging is commonly requested in follow-up of these lesions. Extrinsic mass effect can result in dysregulation of pituitary hormone release as well as extra-pituitary dysfunction.


Neuroendocrine Imaging

Neuroendocrine Imaging. The hypothalamic pituitary axis consists of two separate neuroendocrine organs: the anterior pituitary system and the posterior pituitary system. The hormones of the anterior pituitary are thyroid-stimulating hormone, adrenal corticotrophic hormone, prolactin, growth hormone, and the gonadotropins. These are secreted under the influence of hypothalamic trophic factors. The posterior pituitary gland consists of axonal terminations of neurons whose cell bodies are located in the hypothalamus. The principal hormones secreted by these cells are oxytocin and vasopressin or antidiuretic hormone. The hypothalamus also participates in complex mediation of food intake, temperature regulation, sleep and arousal, memory, thirst, and other autonomic functions.


Neuroendocrine Imaging

Neuroendocrine Imaging. Special Imaging Considerations This guideline emphasizes the initial imaging for diagnosis. Additional studies may be ordered specifically for image-guided surgical navigation systems or intraoperative imaging platforms. It is recommended that ordering physicians consult with their radiologists as to protocols that can accomplish surgical guidance needs, to minimize patient recall or reimaging [7-10]. Endoscopic surgical landmarks requiring presurgical assessment include evaluation for presence of sinus inflammatory disease, sphenoid sinus pneumatization, bony spurs, variant anatomy, and bony dehiscence overlying the internal carotid arteries within the sphenoid sinuses [11-13].


Neuroendocrine Imaging

Neuroendocrine Imaging. Discussion of Procedures by Variant Variant 1: Adult. Suspected or known hypofunctioning pituitary gland (hypopituitarism, growth hormone deficiency, growth deceleration, panhypopituitarism, hypogonadotropic hypogonadism). Initial imaging. Pituitary hypofunction can be caused by mass effect from extrinsic solid or cystic lesions, or from intrinsic pituitary abnormalities. Small prolactin-secreting adenomas in males may result in hypogonadotropic


Neuroendocrine Imaging

Neuroendocrine Imaging. Department of Defense, or United States Government. Reprint requests to: publications@acr.org


Neuroendocrine Imaging

Neuroendocrine Imaging

Neuroendocrine Imaging. Neuroendocrine Imaging


Neuroendocrine Imaging

Neuroendocrine Imaging. hypogonadism, with loss of libido and impotence [14]. Other common mass lesions that may affect the neuroendocrine system are germ-line tumors, meningioma, craniopharyngioma, and Rathke cleft cyst, among others [2,15-18]. Metastatic lesions, sarcoid, and other inflammatory processes may involve the sella and parasellar regions as well. Additionally, an empty sella may be seen with herniation of the subarachnoid space into the sella turcica; while this is usually an incidental finding, close to 30% of patients may demonstrate some hypopituitarism upon testing [19].


Neuroendocrine Imaging

Neuroendocrine Imaging. CT Sella CT can be used to detect bone-destructive lesions of the skull base, which may affect the sella turcica and can also detect larger macroadenomas. Even with an optimized technique, CT for pituitary pathology is insensitive when compared to MRI [12]. Intravenous (IV) contrast may be useful to characterize lesions or assess for soft-tissue invasion, but it should not be considered a first-line imaging test. CT using dual-energy techniques may discriminate larger pituitary masses from other lesions, such as meningioma [18]. Solid masses are more easily defined compared to cystic lesions, which may be confused with cerebral spinal fluid in the suprasellar cistern. CT features of selected suprasellar masses may aid in their characterization. Tumor invasion of the cavernous sinuses can be difficult to detect and may be aided by IV contrast as an adjunctive test. Dual-phase imaging with and without IV contrast is not indicated as an initial imaging study. Thin-section acquisition with multiplanar reformatting is essential and vastly improved over direct coronal imaging. This can also aid intraoperative navigation and provide greater osseous detail for anatomy in the sphenoid sinus prior to trans-sphenoidal surgery.


Neuroendocrine Imaging

Neuroendocrine Imaging. CTA Head CT angiography (CTA) is indicated when vascular lesions, such as aneurysm, are suspected, though these rarely cause clinical symptoms referable to the hypothalamic pituitary axis. Cavernous sinus invasion by pituitary masses can be better detected with CTA compared with noncontrast CT. CTA may be part of operative planning or image guidance; however, CTA is not routinely used for initial evaluation [20].


Neuroendocrine Imaging

Neuroendocrine Imaging. MRA Head MR angiography (MRA) can be a useful adjunct to pituitary MRI and can reliably depict vascular lesions, such as aneurysms [21,22], though these rarely cause clinical symptoms referable to the hypothalamic pituitary axis. Displacement or encasement of vessels in the suprasellar region can be better defined with MRA for surgical planning; however, MRA is not routinely used for initial evaluation.


Neuroendocrine Imaging

Neuroendocrine Imaging. MRI Sella MRI using high-resolution pituitary protocols is the preferred diagnostic imaging modality for evaluation of the pituitary and sellar regions [1,2,23-28]. Anatomy and pathologies involving the pituitary gland, infundibulum, optic chiasm, and vascular structures are reliably depicted and can be characterized on both precontrast and postcontrast imaging, particularly with the aid of high-resolution, focused field-of-view sequences targeted for sellar and parasellar assessment [29-63]. MRI with and without IV contrast plays an important role in characterizing lesions of the sella, suprasellar cistern, and any cavernous sinus invasion [64,65]. MRI with IV contrast may only be performed for use in operative guidance, and should not be considered a first-line imaging test. MRI can confirm absence or ectopia of the posterior pituitary gland. Pituitary underdevelopment may be suggested on the basis of imaging; however, objective criteria for pituitary hypoplasia do not exist [40,42,48]. An empty sella is well characterized on MRI, even without IV contrast [19].


Neuroendocrine Imaging

Neuroendocrine Imaging. Venous Sampling Petrosal Sinus Venous sampling of the cavernous sinuses is not useful in the setting of pituitary hypofunction. Venous sampling is reserved for cases in which a definite excess of pituitary hormone is present, medical management has failed, cross-sectional imaging is negative or equivocal, and surgery is planned [66-68].


Neuroendocrine Imaging

Neuroendocrine Imaging. Radiography Sella Radiography is insensitive and nonspecific for evaluating sellar pathology. Pituitary adenomas are frequently associated with a normal sella size. The sella turcica can be enlarged by the presence of a pituitary adenoma or other pathophysiological conditions such as pulsation of cerebral spinal fluid through a developmental or acquired dehiscence of the diaphragm sella in the empty sella syndrome [69].


Neuroendocrine Imaging

Neuroendocrine Imaging


Neuroendocrine Imaging

Neuroendocrine Imaging. CT Sella CT has the ability to identify large pituitary tumors, and contrast-enhanced CT may define some microadenomas [28,70-73], although MRI is more sensitive. Dual-phase imaging with and without IV contrast is not indicated as an initial imaging study. Larger tumors may cause sellar remodeling, including sellar enlargement, bony erosion, supra sellar extension, invasion into the clivus, or sphenoid sinus.


Neuroendocrine Imaging

Neuroendocrine Imaging. CTA Head CTA may be part of operative planning or image guidance; however, CTA is not routinely used in the initial evaluation of known or suspected hyperfunctioning pituitary adenoma [20].


Neuroendocrine Imaging

Neuroendocrine Imaging. MRA Head There is no relevant literature regarding the use of MRA in the initial imaging evaluation of suspected or known hyperfunctioning pituitary adenoma.