Penetrating Torso Trauma

Penetrating Torso Trauma. CT Chest With IV Contrast Contrast-enhanced chest CT is an effective screening tool for determining the wound trajectory and likelihood of injury to mediastinal structures. CT can guide the decision-making process in management of patients in whom immediate surgical intervention could be performed with positive findings at CT chest [51]. If CT shows no evidence of mediastinal injury or other thoracic injury requiring surgery, the patient can simply be observed [37].


Penetrating Torso Trauma

Penetrating Torso Trauma. CT Chest Without And With IV Contrast There is no relevant literature regarding the use of CT chest without and with IV contrast for initial evaluation of penetrating torso trauma isolated to the chest. The addition of a noncontrast phase does not provide additional information pertinent to penetrating trauma [31].


Penetrating Torso Trauma

Penetrating Torso Trauma. CT Chest Without IV Contrast Although noncontrast CT may be helpful in determining trajectory, demonstration of internal injuries, specifically solid organs, is much more apparent with IV contrast. Vascular injuries are also better depicted with IV contrast. CT chest without IV contrast can effectively excluded pneumothorax and hemothorax [50]. During the global shortage of contrast in 2022, unenhanced CT scans were used for acute and posttraumatic patients in emergency departments at some institutions [36].


Penetrating Torso Trauma

Penetrating Torso Trauma. CTA Abdomen and Pelvis With IV Contrast In the hemodynamically stable patient population, multiphasic imaging can provide additional useful information regarding the source of active bleeding. Additionally, it is important to remember that imaging can be performed after damage control surgery to identify injuries that may need definitive treatment [29,33].


Penetrating Torso Trauma

Penetrating Torso Trauma. CTA Chest With IV Contrast In the hemodynamically stable patient population, CTA can provide additional useful information regarding the source of active bleeding. Additionally, it is important to remember that imaging can be performed after damage control surgery to identify injuries that may need definitive treatment [29,33]. In their retrospective study, Nummela et al [29] found that arterial and venous phases of the chest, abdomen, and pelvis CT facilitated recognition of active bleeding in patients with penetrating thoracic trauma. Differentiating between arterial and venous hemorrhage may have treatment implications. For example, a hemodynamically stable patient with active arterial bleeding may be treated with an angioembolization procedure, whereas bleeding from a venous structure may result in supportive care [29,33].


Penetrating Torso Trauma

Penetrating Torso Trauma. MRI Abdomen and Pelvis Without and With IV Contrast There is no relevant literature regarding the use of MRI chest, abdomen, and pelvis without and with IV contrast for initial evaluation of patients with penetrating torso trauma.


Penetrating Torso Trauma

Penetrating Torso Trauma. MRI Abdomen and Pelvis Without IV Contrast There is no relevant literature regarding the use of MRI chest, abdomen, and pelvis without IV contrast for initial evaluation of patients with penetrating torso trauma with hypotension.


Penetrating Torso Trauma

Penetrating Torso Trauma. MRI Chest Without and With IV Contrast There is no relevant literature regarding the use of MRI chest without and with IV contrast only for initial evaluation of patients with penetrating torso trauma.


Penetrating Torso Trauma

Penetrating Torso Trauma. MRI Chest Without IV Contrast There is no relevant literature regarding the use of MRI chest without IV contrast only for initial evaluation of patients with penetrating torso trauma.


Penetrating Torso Trauma

Penetrating Torso Trauma

Penetrating Torso Trauma. Penetrating Torso Trauma


Penetrating Torso Trauma

Penetrating Torso Trauma. Radiography Trauma Series Penetrating trauma occurring outside of the thoracoabdominal zones and the cardiac box maybe sufficiently imaged with radiography in clinically stable patients [51]. Normal radiographic appearance of the chest does not preclude significant thoracic trauma that may require procedural or surgical intervention [50].


Penetrating Torso Trauma

Penetrating Torso Trauma. Variant 7: Adult. Nonballistic penetrating torso trauma, limited to abdomen and pelvis, normotensive. Initial imaging. FAST can help triage patients and direct initial bedside and surgical procedures. Hemopericardium, pneumothorax, and free intraperitoneal fluid discovered at FAST have significant implications on next steps in management of the patient.


Penetrating Torso Trauma

Penetrating Torso Trauma. CT Abdomen and Pelvis Without and With IV Contrast There is no relevant literature regarding the use of CT abdomen and pelvis without and with IV contrast for initial evaluation of penetrating torso trauma isolated to the chest. The addition of a noncontrast phase adds radiation exposure to the patient and may delay definitive diagnosis and typically does not provide additional information pertinent to penetrating trauma [31].


Penetrating Torso Trauma

Penetrating Torso Trauma. CT Abdomen and Pelvis Without IV Contrast There is no relevant literature regarding the use of CT abdomen and pelvis without IV contrast for initial evaluation of penetrating torso trauma. Although noncontrast CT may be helpful in determining trajectory, demonstration of internal injuries, specifically solid organs, is much more apparent with IV contrast. During the global shortage of contrast in 2022, unenhanced CT scans were used for acute and posttraumatic patients in emergency departments at some institutions [36].


Penetrating Torso Trauma

Penetrating Torso Trauma. CT Chest With IV Contrast CT chest may be used if there is suspicion of supradiaphragmatic injury involving the lungs, heart, diaphragm, or pleural space.


Penetrating Torso Trauma

Penetrating Torso Trauma. CT Chest Without and With IV Contrast There is no relevant literature regarding the use of CT chest without and with IV contrast for initial evaluation of penetrating torso trauma limited to the abdomen and pelvis.


Penetrating Torso Trauma

Penetrating Torso Trauma. CT Chest Without IV Contrast There is no relevant literature regarding the use of CT chest without IV contrast for initial evaluation of penetrating torso trauma limited to the abdomen and pelvis. The addition of a noncontrast phase does not provide additional information pertinent to penetrating trauma [31].


Penetrating Torso Trauma


Penetrating Torso Trauma

Penetrating Torso Trauma


Penetrating Torso Trauma

Penetrating Torso Trauma. MRI Abdomen and Pelvis Without and With IV Contrast There is no relevant literature regarding the use of MRI abdomen and pelvis without and with IV contrast for initial evaluation of patients with penetrating torso trauma.


Penetrating Torso Trauma

Penetrating Torso Trauma. MRI Abdomen and Pelvis Without IV Contrast There is no relevant literature regarding the use of MRI abdomen and pelvis without IV contrast for initial evaluation of patients with penetrating torso trauma with hypotension.


Penetrating Torso Trauma

Penetrating Torso Trauma. MRI Chest Without and With IV Contrast There is no relevant literature regarding the use of MRI chest without and with IV contrast for initial evaluation of patients with penetrating torso trauma.


Penetrating Torso Trauma

Penetrating Torso Trauma. MRI Chest Without IV Contrast There is no relevant literature regarding the use of MRI chest without IV contrast for initial evaluation of patients with penetrating torso trauma with hypotension.


Penetrating Torso Trauma

Penetrating Torso Trauma. 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.


Penetrating Torso Trauma

Penetrating Torso Trauma. For additional information on the Appropriateness Criteria methodology and other supporting documents go to www.acr.org/ac.


Renovascular Hypertension

Renovascular Hypertension. Introduction/Background Hypertension is a common condition, affecting approximately 20% of adults. Secondary hypertension (ie, hypertension with a demonstrable cause) accounts for only 5% to 10% of all cases of hypertension, with the remaining cases considered primary hypertension or essential hypertension. Renovascular hypertension is the most common type of secondary hypertension and is estimated to have a prevalence between 0.5% and 5% of the general hypertensive population, and it has an even higher prevalence among patients with severe hypertension and end-stage renal disease, approaching 25% in elderly dialysis patients [1]. There are varied causes of reduced renal perfusion with resultant renovascular hypertension, the most common being renal artery stenosis (RAS) secondary to either atherosclerotic disease (90%) or fibromuscular dysplasia (10%) [2]. Less common etiologies include vasculitis, embolic disease, dissection, post-traumatic occlusion, and extrinsic compression of a renal artery or of a kidney [3]. Clinical features associated with an increased likelihood of renovascular hypertension include an abdominal bruit, malignant or accelerated hypertension, significant (diastolic pressure >110 mm Hg) hypertension in a young adult (<35 years of age), new onset after 50 years of age, sudden development or worsening of hypertension, refractory hypertension, deterioration of renal function in response to angiotensin- converting enzyme inhibitors, and generalized arteriosclerotic occlusive disease with hypertension.


Renovascular Hypertension

Renovascular Hypertension. A critical problem in diagnosing renovascular hypertension is the selection of an appropriate end point against which to judge the accuracy of new tests. Calculations of the sensitivity, specificity, and accuracy of these examinations are normally based on a comparison with a standard such as conventional angiography. However, the definition of a significant RAS has varied. Most investigators consider a 50% to 60% stenosis to be significant, yet perfusion pressure in a large artery is generally not reduced until stenosis exceeds 70% to 75%. Ultimately, the defining criterion for renovascular hypertension is a fall in blood pressure after intervention (angioplasty, intravascular stent placement, or surgery). Bilateral renal artery disease remains a problem in that it is difficult in such cases to quantify the effect on blood pressure of one side versus the other.


Renovascular Hypertension

Renovascular Hypertension. 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.


Renovascular Hypertension

Renovascular Hypertension. Reprint requests to: publications@acr.org


Renovascular Hypertension

Renovascular Hypertension

Renovascular Hypertension. Renovascular Hypertension


Renovascular Hypertension

Renovascular Hypertension. Discussion of Procedures by Variant Variant 1: High index of suspicion of renovascular hypertension. Normal renal function. US Duplex Doppler US is an attractive technique as a noninvasive screening test in that it does not require intravenous contrast material and can be used in patients with any level of renal function. As with many of the noninvasive imaging examinations, there are numerous parameters and abnormal criteria indicating possible renovascular disease.


Renovascular Hypertension

Renovascular Hypertension. Doppler US can also be used for detection of significant renal artery in-stent restenosis, though studies have shown that compared with native renal arteries, higher PSV and RAR values are indicative of stenosis in stented arteries. Chi et al [18], in a study of 67 patients with renal artery stents, found that a PSV of at least 395 cm/s or RAR of at least 5.1 was most predictive of significant in-stent stenosis. Similarly, Del Conde et al [19], in a study of 132 stented renal arteries, reported a mean PSV of 382 cm/s and RAR of 5.3 in arteries with >60% stenosis.


Renovascular Hypertension

Renovascular Hypertension


Renovascular Hypertension

Renovascular Hypertension. Although Doppler US is a preferred screening tool for RAS, it is time-consuming and highly operator dependent, and MRI or CT may be more reliable modalities for operators who are less experienced with US for RAS.


Renovascular Hypertension

Renovascular Hypertension. Nuclear Medicine Renal scintigraphy was first used for evaluating renal function in the late 1950s. Initial attempts to use renography specifically for evaluating renovascular hypertension had a high rate of false-positive and false-negative results. Captopril was later added to the examination in an attempt to improve the accuracy of the test for diagnosing renovascular hypertension and for predicting blood pressure reduction after surgery or angioplasty. Administration of an angiotensin-converting enzyme inhibitor such as captopril leads to a decrease in glomerular filtration pressure, prolonged transit time of tubular agents such as Tc-99m-MAG3, and decreased uptake of glomerular agents such as Tc-99m-diethylenetriaminepentaacetic acid.


Renovascular Hypertension

Renovascular Hypertension. Captopril renal scintigraphy analysis is based on characterization of renal function deterioration when compared with a baseline study, with decreased glomerular filtration rate reflected in time-activity curves. Captopril renography is therefore a functional assessment of renal perfusion and function rather than a method of directly visualizing the vasculature. The sensitivity and specificity of this examination are decreased in patients without clinical features of renovascular hypertension and are also decreased in patients with bilateral RAS, impaired renal function, and urinary obstruction [20]. The reported sensitivity of captopril renal scintigraphy for renovascular hypertension ranges from 34% to 93%, with a meta-analysis of 14 studies between 1990 and 2000 by Vasbinder et al [21] showing a mean sensitivity of approximately 81%. There have also been inconsistent results regarding the predictive value of captopril renal scintigraphy in identifying patients who will respond to revascularization. High correlation between a positive result on captopril renal scintigraphy and reduction in blood pressure after intervention has been reported in some studies [22]. However, the predictive value has been dismissed in other studies, with reported positive predictive values as low as 51% [23-26].


Renovascular Hypertension

Renovascular Hypertension. In summary, captopril renal scintigraphy has decreased sensitivity and specificity in patients with bilateral stenosis and impaired renal function, but it can be a useful tool for detecting renovascular hypertension in appropriately selected patients. As a functional evaluation of renal perfusion and function, captopril scintigraphy can be useful to determine the physiologic sequence of a known stenosis and to assess the relative function of each kidney before intervention [27,28].


Renovascular Hypertension

Renovascular Hypertension. MRA MRA is suited for noninvasive workup of RAS and has been widely applied in clinical practice. The reliability of MRA is not affected by the presence of bilateral renovascular disease. It is unnecessary to hydrate the patients or to stop diuretics before the examination. Three-dimensional contrast-enhanced MRA with an intravenous injection of gadolinium-based contrast agent has been the backbone of MRI examinations of renal arteries, but noncontrast MRA with steady-state free precession (SSFP) and arterial spin labeling techniques has also been used for evaluating the renal arteries.


Renovascular Hypertension

Renovascular Hypertension. CTA CTA Contrast-enhanced CTA provides accurate anatomic images of the renal arteries with isotropic data sets that enable the reconstruction of high-resolution images in any plane. As with conventional angiography, the disadvantages of this technique are its ionizing radiation and its use of nephrotoxic contrast material. Advantages compared with arteriography include less invasiveness, faster acquisitions, and multiplanar imaging [40]. Two


Renovascular Hypertension

Renovascular Hypertension. Renovascular Hypertension studies comparing CTA with digital renal arteriography have reported the sensitivity of CTA for detecting stenoses (>50% diameter) to be 88% to 96% and the specificity to be 77% to 98%, and in one study the accuracy was 89%. In diagnosing narrowing of only the main renal arteries, one study found the sensitivity and specificity to be 100% and 98%, respectively [41,42]. Normal results from CTA virtually rule out RAS. Both maximum- intensity projection and volume-rendering techniques are useful and complementary in CT evaluation of RAS [43]. Secondary signs include poststenotic dilatation, renal atrophy, and decreased cortical enhancement. A threshold of 800 mm2 for cortical area and 8 mm for mean cortical thickness seen on CT can be useful morphologic markers of atherosclerotic renal disease [44].


Renovascular Hypertension

Renovascular Hypertension. Like MRA, CTA is more accurate in diagnosing proximal rather than distal lesions, though in general CTA provides better depiction of branch renal arteries than MRA [45]. CTA can also be used to assess patency of renal stents [44,46,47]. Steinwender et al [48] described CTA evaluation of 95 renal artery stents in which 98% of the stents were assessable on CTA, and there was 100% sensitivity and 99% specificity for detecting in-stent stenosis.


Renovascular Hypertension

Renovascular Hypertension. Arteriography Intra-arterial digital subtraction angiography (IADSA) is considered the reference standard for demonstrating RAS and is an integral part of angioplasty and stenting procedures. Angiography has high spatial resolution for evaluating the main renal arteries as well as the branch renal arteries. There is high interobserver agreement for identification of severe stenoses by angiography [49], but there is reported substantial interobserver variability in visual estimation of moderate RAS. IADSA allows for measurement of pressure gradients across a stenosis, providing assessment of its hemodynamic significance before intervention. A pressure gradient >20 mm Hg, or >10% of mean arterial pressure, is considered to be an indicator of hemodynamic significance [50,51].


Renovascular Hypertension

Renovascular Hypertension. Smith et al [52], in a small study of 19 patients, reported the sensitivity and specificity of intravenous digital subtraction angiography (IVDSA) to be as high as 87%. However, false-positive rates ranged from 26% to 37%, which they attributed to limited spatial resolution, subtraction artifacts, and quantum noise. Other reported limitations of this technique have included obscuration of renal artery stenoses by overlap with opacified mesenteric vessels and also suboptimal evaluation of fibromuscular lesions [53-55]. Wilms et al [55], in a study of 45 patients, found fewer false-positives, which they attributed to technical advances and software improvements. They also reported that IVDSA grading of stenosis was accurate in 94% of cases of atherosclerotic RAS but in only 56% of fibromuscular stenosis cases. Dunnick et al [56], in a prospective study of 94 patients, reported 100% sensitivity and 93% specificity for RAS, though the 100% sensitivity was achieved in part by including inadequate examinations as positive, and the authors acknowledged the limitations of IVDSA for evaluating vessels affected by fibromuscular dysplasia. Although good results can be achieved with IVDSA, its resolution is inferior compared with that of IADSA, and it is less sensitive than IADSA for evaluating fibromuscular dysplasia and atherosclerotic stenosis of branch vessels. In addition, the contrast dose is often substantially higher than in arteriography and requires central injection in the inferior vena cava or right atrium. For these reasons, IVDSA is not utilized as a screening examination for renovascular hypertension.


Renovascular Hypertension

Renovascular Hypertension. Variant 2: High index of suspicion of renovascular hypertension. Decreased renal function, eGFR <30 mL/min/1.73 m2. The selection of imaging modality and technique for evaluation of RAS may vary in the setting of decreased renal function primarily because of the risk of CIN with iodinated contrast material for CT and the risk of NSF with gadolinium-based contrast agents for MRI.


Renovascular Hypertension

Renovascular Hypertension. US For patients with a high index of suspicion for renovascular disease and diminished renal function, duplex Doppler US is a preferred screening examination, especially at a site where the technique has proven to be reliable and where dedicated technologists and physicians are skilled in the examination and can perform it with a high degree of accuracy. The technical details of the examination and the threshold criteria are similar to those used for patients with normal renal function (see variant 1).


Renovascular Hypertension

Renovascular Hypertension. CTA Depending on the degree of impaired renal function, contrast-enhanced CTA has been considered to be precluded because of potential nephrotoxicity of contrast material. However, the causal relationship between contrast material for CT and acute kidney injury has been disputed, and recent data suggest a low risk of clinically relevant CIN. Cutoff values for serum creatinine and estimated glomerular filtration rate (eGFR) beyond which iodinated contrast material would not be administered vary by institution, though eGFR is recognized to be a better indicator of baseline renal function than serum creatinine. Recent large studies from Davenport et al in 2013 and McDonald et al in 2014 indicate that intravenous iodinated contrast material is not an independent nephrotoxic risk factor in patients with a stable baseline eGFR of >45 mL/min/1.73 m2 and that iodinated contrast material is rarely nephrotoxic in patients with a stable baseline eGFR of 30 to 44 mL/min/1.73 m2 [60-63]. Conflicting results were obtained for patients with more severe renal dysfunction with an eGFR of <30 mL/min/1.73 m2, with the 2013 Davenport et al study reporting an excess of acute kidney injury in these patients receiving intravenous contrast material versus controls but with the 2014 McDonald et al study showing no significant difference in acute kidney injury for contrast material recipients versus control patients with this baseline eGFR [8,60-63]. The ACR Manual on Contrast Media notes that if a threshold for CIN risk is used, an eGFR of 30 mL/min/1.73 m2 has the greatest level of evidence [7]. Reduced iodine dose should be considered in patients with borderline renal function, but other parameters are similar to patients with normal renal function. Unenhanced CT does not provide useful diagnostic information regarding RAS.


Renovascular Hypertension

Renovascular Hypertension. MRA Contrast-enhanced MRA may be precluded because of the risk of NSF with eGFR <30 mL/min/1.73 m2. In these patients, unenhanced MRA techniques are available as an alternative to contrast-enhanced MRA to avoid the risk of NSF. Utsunomiya et al [64], comparing unenhanced SSFP MRA with CT or IADSA in 26 patients, found a sensitivity, specificity, positive predictive value, and negative predictive value of 78%, 91%, 64%, and 96%, respectively. Mohrs et al [65], comparing an SSFP technique with contrast-enhanced MRA in 45 patients, found a sensitivity, specificity, positive predictive value, and negative predictive value of 75%, 99%, 75%, and 99%, respectively, for detecting renal artery stenoses >50%. Braidy et al [66] compared an unenhanced SSFP technique to contrast-enhanced MRA with a sensitivity, specificity, positive predictive value, and negative predictive value of 85%, 96%, 94%, and 96%, respectively, but emphasized that when stenosis is found, other modalities should be employed for better estimation. Albert et al [67], in a report of a multicenter trial of 75 patients, compared an unenhanced MRA technique to contrast-enhanced CT with a sensitivity of 74% and specificity of 93% for >50% stenosis.


Renovascular Hypertension

Renovascular Hypertension. Arteriography and Venography Impaired renal function may also limit the use of iodinated contrast material for angiography-based interventional procedures. Carbon dioxide, supplemented by limited use of gadolinium-based agents when mild to moderate decreased function allows, have both been used as alternatives to iodinated contrast in patients for whom iodinated contrast is contraindicated, though images obtained with these alternative contrast agents are less desirable when compared with those obtained with iodinated contrast material [68,69].


Renovascular Hypertension

Renovascular Hypertension. Nuclear Medicine Captopril renal scintigraphy is not a reliable test in patients with poor renal function.


Renovascular Hypertension

Renovascular Hypertension

Renovascular Hypertension. Renovascular Hypertension


Renovascular Hypertension

Renovascular Hypertension. Although there are references that report on studies with design limitations, 21 well-designed or good-quality studies provide good evidence.


Renovascular Hypertension

Renovascular Hypertension. Supporting Documents For additional information on the Appropriateness Criteria methodology and other supporting documents go to www.acr.org/ac.


Renovascular Hypertension

Renovascular Hypertension


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. 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.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. OR aUniversity of California Los Angeles, Los Angeles, California. bPanel Chair, Montefiore Medical Center, Bronx, New York. cPanel Vice-Chair, Uniformed Services University, Bethesda, Maryland. dOhio State University, Columbus, Ohio. eMichigan State University, East Lansing, Michigan; American College of Emergency Physicians. fOttawa Hospital Research Institute and the Department of Radiology, The University of Ottawa, Ottawa, Ontario, Canada; Canadian Association of Radiologists. gEmory University, Atlanta, Georgia. hBarrow Neurological Institute, Phoenix, Arizona; Neurosurgery expert. iMayo Clinic, Rochester, Minnesota. jUniversity of New Mexico, Albuquerque, New Mexico; American College of Physicians. kEinstein Healthcare Network, Philadelphia, Pennsylvania. lUniversity of California San Diego Medical Center, San Diego, California. mOregon Health & Science University, Portland, Oregon. nUniversity of North Carolina School of Medicine, Chapel Hill, North Carolina; American Academy of Neurology. oAlbany ENT & Allergy Services, PC, Albany, New York; American Academy of Otolaryngology-Head and Neck Surgery. pAlbert Einstein College of Medicine Montefiore Medical Center, Bronx, New York, Internal medicine physician. qColumbia University Medical Center, New York, New York. rUniversity of Cincinnati Medical Center, Cincinnati, Ohio. sSpecialty Chair, Atlanta VA Health Care System and Emory University, Atlanta, Georgia.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. The American College of Radiology seeks and encourages collaboration with other organizations on the development of the ACR Appropriateness Criteria through representation of such organizations on expert panels. Participation on the expert panel does not necessarily imply endorsement of the final document by individual contributors or their respective organization.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. Reprint requests to: publications@acr.org


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. This variant will focus on imaging examinations used to determine the source of SAH after initial detection. SAH, involving the basal cisterns, requires rapid triage and workup because a ruptured cerebral aneurysm is responsible for 70% of all nontraumatic SAHs [4,5]. The overall incidence of aneurysmal SAH in the United States is between 9.7 and 14.5 cases per 100,000 population and may be underestimated due to the high risk of death prior to hospital admission [6-9]. Aneurysmal SAH results in significant morbidity and mortality with a quarter of aneurysmal subarachnoid patients dying after presentation; therefore, early diagnosis and repair is crucial to prevent rebleeding [6]. Less common causes of SAH, often presenting as isolated convexity SAH, such as tumors, stroke transformation, cerebral amyloid angiopathy, or reversible cerebral vasoconstriction syndrome, are not considered here as their imaging and diagnosis often follows the initial, commonly emergent, imaging revaluation for common vascular lesions. Follow-up imaging for delayed complications of SAH, such as hydrocephalus, should be directed by local protocols and clinical symptoms. The delayed complication of vasospasm after SAH is discussed in Variant 2 of this topic.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. Arteriography Cervicocerebral Catheter-directed angiography of the cerebral vasculature demonstrates high spatial resolution, large field of view, and dynamic acquisition that leads to high diagnostic value in the evaluation of cerebrovascular diseases resulting in SAH. Sensitivity and specificity are both >98% for catheter cerebral angiography when compared with surgical findings, including small aneurysms <3 mm [10]. Catheter cerebral angiography also identified vascular abnormalities in up to 13% of patients with SAH and negative CTA imaging [11]. Although catheter cerebral angiography has been reported to be negative in 2% to 24% of patients with aneurysmal SAH, 3-D rotational angiography has been shown to identify an aneurysm on 25% of previously angiogram, both 2-D and 3-D, negative patients [12]. Angiography is an invasive procedure with a small complication risk related to intravascular instrumentation.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. CT Head Perfusion There is no relevant literature to support the use of CT head perfusion in the evaluation of known acute SAH.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. CTA Head CTA head is a fast, noninvasive study to evaluate patients with acute SAH. CTA head has been shown to have >90% sensitivity and specificity in the evaluation for aneurysms [4,10,13-18] responsible for SAHs. However, CTA head sensitivity for detecting aneurysm decreases for aneurysms <3 mm in size [4,10,13,15,17,19], in the setting of diffuse SAH [20], and for aneurysms occurring adjacent to an osseous structure [19]. CTA head may be sufficient to rule out a vascular cause of SAH when the location of hemorrhage is isolated to the perimesencephalic region with follow-up catheter-directed angiography indicated in CTA negative diffuse or peripheral SAHs [20].


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. CTA Neck There is no relevant literature to support the use of CTA neck in the initial imaging evaluation of known acute SAH. CTA neck may be useful for potential treatment planning, but preference will be individual or site specific.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. CTV Head There is no relevant literature to support the use of CT venography (CTV) head in the evaluation of known acute SAH.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. CVD-Aneurysm, Vascular Malformation, and SAH MRA Head MR angiography (MRA) head for the evaluation of intracranial aneurysm demonstrated a pooled sensitivity of 95% and specificity of 89% in one meta-analysis [21]. Diagnostic accuracy is increased, including for aneurysms >5 mm in size and at 3T scanner strength [21,22]. The decrease in specificity, when compared with CTA, is reported to have false-positive cases related to normal vascular variants of infundibular origin of vessels and vessel loops [23]. Limitations of MRA head include required safety screening and relatively long acquisition time in urgent clinical scenarios.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. MRA Neck There is no relevant literature to support the use of MRA neck in the evaluation of known acute SAH. MRA neck may be useful for potential treatment planning, but preference will be individual or site specific.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. MRI Head Perfusion There is no relevant literature to support the use of MRI head perfusion in the evaluation of known acute SAH.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. MRI Head Although there is no relevant literature to support the use of MRI head in the evaluation for a vascular source of known acute SAH, several studies evaluated the use of MRI head in predicting clinical outcomes. Patients with acute poor-grade SAH and diffusion-weighted imaging positive findings on MRI head had a less favorable long- term outcome when compared with patients without diffusion-weighted imaging positive findings [24,25].


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. MRV Head There is no relevant literature to support the use of MR venography (MRV) head in the evaluation of known acute SAH.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. US Duplex Doppler Carotid Artery There is no relevant literature to support the use of carotid artery ultrasound (US) duplex Doppler in the evaluation of known acute SAH.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. US Duplex Doppler Transcranial There is no relevant literature to support the use of US transcranial with duplex Doppler (TCD) in the evaluation of known acute SAH.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. Variant 2: Suspected cerebral vasospasm. Initial imaging. Vasospasm in the cerebral arteries occurs in approximately 30% of patients with SAH and frequently occurs 7 to 10 days after hemorrhage with spontaneous resolution by day 21 [6]. Vasospasm is associated with delayed cerebral ischemia defined by delayed development of neurologic deficits after SAH not related to aneurysm treatment or other neurologic complications, such as hydrocephalus, cerebral edema, or metabolic derangements [26]. Morbidity and mortality in SAH increases between 10% and 20% after onset of clinical symptoms of delayed cerebral ischemia [27], and the symptoms are frequently nonreversible [28,29]. Imaging findings of vasospasm and guidance of treatment does not appear to improve clinical outcome after the onset of clinical symptoms [28].


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. Despite the association of moderate to severe vasospasm and poor clinical outcome [30], only 50% patients with large-vessel vasospasm develop clinical ischemic neurologic symptoms [6], and delayed ischemia can occur in the absence of imaging findings of vasospasm [26]. However, given the clinical implications of delayed cerebral ischemia, early screening and detection of vasospasm remains recommended [6].


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. Arteriography Cervicocerebral Conventional catheter-directed cerebrovascular arteriography is the reference standard for characterization of intracranial vasospasm. However, only approximately 50% of radiographic large-vessel vasospasm develops delayed cerebral ischemia, and given the invasive nature and potential rare neurologic complications, other less invasive screening methods are often performed before catheter angiogram [28]. In a large, international multicenter randomized trial, the presence of angiographic vasospasm was strongly associated (odds ratio of 9.3) with the development of cerebral infarction. In the same study, a small number of patients (3%) developed infarction without evidence of vasospasm on angiogram [31]. An additional consideration to the angiographic evaluation of vasospasm is the potential for intra-arterial treatment of vessel narrowing. However, intra-arterial treatment of vasospasm lacks high-quality evidence of improvement of outcomes at this time [6].


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. CT Head SAH on CT head can be graded by the Fisher or modified Fisher scale. The higher the Fisher grade of SAH, the higher the patient risk for vasospasm [35]. Although CT head may be useful to provide a Fisher grade and risk for vasospasm, the examination does not directly give information regarding the presence or absence of vasospasm. Anatomic changes of completed infarct related to delayed cerebral ischemia can also be identified on CT head.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. CTA Head CTA head can provide a less invasive evaluation of the intracranial cerebral vasculature compared with catheter- directed angiography. In a meta-analysis, CTA head detected vasospasm with a sensitivity and specificity of 80% and 93%, respectively [33]. CTA head is highly correlated to conventional angiography for larger proximal intracranial vessels with decreasing correlation in the smaller more distal arteries [36].


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. CTA Neck There is no relevant literature to support the use of CTA neck in the evaluation of suspected cerebral vasospasm.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. CTV Head There is no relevant literature to support the use of CTV head in the evaluation of suspected cerebral vasospasm.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. MRA Head There is no relevant literature to support the use of MRA head in the evaluation of suspected cerebral vasospasm.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. MRA head evaluation of the intracranial arteries in the setting of suspected vasospasm is limited by background of hemorrhage and hemodynamic flow alterations with poor correlation to digital subtraction angiography (DSA) findings [37].


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. MRA Neck There is no relevant literature to support the use of MRA neck in the evaluation of suspected cerebral vasospasm.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. MRI Head Perfusion Given the continued difficulty in identifying patients at risk for and in preventing vasospasm and delayed cerebral ischemia, advanced MRI head perfusion studies are now being performed. MRI head perfusion with decreased intravoxel incoherent motion microvascular perfusion has been associated with vasospasm [38], and elevated blood- brain barrier permeability (Ktrans) was associated with patients who went on to develop delayed cerebral ischemia [39]. Despite these early positive studies, no large or prospective studies have been performed to support the widespread use of MRI head perfusion in the evaluation of suspected vasospasm.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. MRI Head MRI head offers evaluation of consequences of delayed cerebral ischemia including completed infarction. However, there is no relevant literature to support the use of MRI head in the evaluation of suspected cerebral vasospasm.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. MRV Head There is no relevant literature to support the use of MRV head in the evaluation of suspected cerebral vasospasm.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. US Duplex Doppler Carotid Artery There is no relevant literature to support the use of carotid artery US duplex Doppler in the evaluation of suspected cerebral vasospasm.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. CVD-Aneurysm, Vascular Malformation, and SAH US Duplex Doppler Transcranial TCD is a quick and noninvasive modality to evaluate for increased arterial velocities in the setting of vasospasm. Given the ability to perform the examination at the bedside, daily TCD is frequently used in the screening for vasospasm in at-risk populations. Vasospasm identified on TCD predicts delayed cerebral ischemia with 90% sensitivity, 92% negative predictive value, 71% specificity, and 57% positive predictive value [40]. Although screening for vasospasm with TCD has high sensitivity and negative predictive value, prolonged TCD screening past day 10 post-SAH does not appear to increase detection of delayed cerebral ischemia [41]. In addition, there is no current high-quality literature relating detection of vasospasm on TCD to improved patient outcomes [40].


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. Variant 3: Known cerebral aneurysm; untreated. Surveillance monitoring. Cerebral aneurysms are often incidentally discovered on intracranial vascular imaging. Definitive algorithmic guidelines for management and follow-up of incidentally found cerebral aneurysms are lacking [42]. Between 4% and 18% of aneurysms demonstrate growth on imaging follow-up [43,44], with a 12-fold higher risk of rupture in growing aneurysms [44]. Although aneurysm growth is associated with size >7 mm, smaller aneurysms can grow and rupture [44]. Given the evidence of potential for growth and rupture of untreated and unruptured aneurysms, vascular imaging surveillance is recommended.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. Arteriography Cervicocerebral Cervicocerebral arteriography remains the reference standard imaging examination for the evaluation of cerebral aneurysms with high spatial resolution, high signal-to-noise ratio, and dynamic image acquisition. However, given the invasive nature and potential complications of cervicocerebral arteriography, it is not ideal for routine patient surveillance.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. CT Head Perfusion There is no relevant literature to support the use of CT head perfusion in the surveillance of a known, untreated cerebral aneurysm.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. CT Head There is no relevant literature to support the use of CT head in the surveillance of a known, untreated cerebral aneurysm.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. CTA Head CTA head is a fast and noninvasive study to evaluate the intracranial vasculature. CTA head has been shown to be >90% sensitive and specific in the evaluation for aneurysms [4,10,13-18]. However, CTA head sensitivity for detecting an aneurysm decreases for aneurysms <3 mm in size [4,10,13,15,17,19] and for aneurysms occurring adjacent to an osseous structure [19].


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. CTA Neck There is no relevant literature to support the use of CTA neck in the surveillance of a known, untreated cerebral aneurysm.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. CTV Head There is no relevant literature to support the use of CTV head in the surveillance of a known, untreated cerebral aneurysm.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. MRA Head MRA head is an ideal candidate for imaging surveillance of known, untreated aneurysms because of its noninvasive nature and ability to obtain diagnostic information without intravenous (IV) contrast. The evaluation of intracranial aneurysm with MRA head demonstrated a pooled sensitivity of 95% and specificity of 89% in one meta-analysis [21]. Diagnostic accuracy is increased, including for aneurysms <5 mm in size, at 3T scanner strength [21,22]. Vessel loops and infundibular origins of vessels can lead to false-positives for aneurysm on MRA [23]. Contrast- enhanced MRA head may increase visualized detail of large aneurysms with complex flow dynamics or thrombosis [45]. However, there is no significant difference in diagnostic performance between time-of-flight MRA and contrast-enhanced MRA on the aforementioned meta-analysis of MRA examinations in the diagnosis of aneurysms [21].


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. MRA Neck There is no relevant literature to support the use of MRA neck in the surveillance of a known, untreated cerebral aneurysm.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. CVD-Aneurysm, Vascular Malformation, and SAH MRI Head Perfusion There is no relevant literature to support the use of MRI head perfusion in the surveillance of a known, untreated cerebral aneurysm.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. MRI Head There is no relevant literature to support the use of MRI head in the surveillance of a known, untreated cerebral aneurysm.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. MRV Head There is no relevant literature to support the use of MRV head in the surveillance of a known, untreated cerebral aneurysm.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. US Duplex Doppler Carotid Artery There is no relevant literature to support the use of carotid artery US duplex Doppler in the surveillance of a known, untreated cerebral aneurysm.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. US Duplex Doppler Transcranial There is no relevant literature to support the use of TCD in the surveillance of a known, untreated cerebral aneurysm.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. Variant 4: Known cerebral aneurysm; previously treated. Surveillance monitoring. Treatment of cerebral aneurysms is common to reduce the risk of aneurysm rupture or rebleeding. Endovascular treatment is now the first-line therapy in most cases, whereas aneurysms not amenable to endovascular repair require surgical clipping or observation. Follow-up imaging after treatment is often performed to assess for potential refilling of aneurysms and detect formation of new aneurysms. Aneurysm remnants after surgical clipping are identified in up to 11% of patients [46] and more frequently after endovascular repair [47,48]. Recurrence of treated aneurysm is most common within 6 months of treatment but can occur in a more delayed manner [49]. Development of de novo aneurysm occurs in 1% to 8% of patients with treated aneurysms [50-52].


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. Imaging evaluation is focused on not only the treated aneurysm but also the integrity of the parent vessel and formation of new aneurysms. Intracranial aneurysms are treated with several different devices, including surgical clips, detachable coils, stents, and flow diverters, and each device will result in unique appearances as well as challenges, depending on the imaging modality used. Specific knowledge of the technique utilized in prior treatment is helpful in choosing a particular follow-up modality for each patient.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. Arteriography Cervicocerebral Cervicocerebral arteriography remains the reference standard imaging examination for the evaluation of treated cerebral aneurysms with high spatial resolution, high signal-to-noise ratio, and dynamic image acquisition. Aneurysm and parent vessel appearance is better visualized, as indwelling occlusion device artifacts are less apparent on cervicocerebral arteriography than on MRI or CT. Drawbacks for surveillance include invasiveness and small risk of vascular complication.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. CT Head Perfusion There is no relevant literature to support the use of CT head perfusion in the surveillance of known, treated cerebral aneurysm.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. CT Head There is no relevant literature to support the use of CT head in the surveillance of known, treated cerebral aneurysm.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. CTA Head CTA head is useful for surveillance imaging of treated cerebral aneurysms because of its noninvasive nature. However, CTA is limited by large metallic streak artifacts encountered with metallic coils, stents, and devices. Although artifact from metal cannot be removed, several metal artifact reduction techniques are available to improve evaluation of treated aneurysms and the parent vessels [53-57].


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. CTA Neck There is no relevant literature to support the use of CTA neck in the surveillance of known, treated cerebral aneurysm.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. CTV Head There is no relevant literature to support the use of CTV head in the surveillance of known, treated cerebral aneurysm.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. CVD-Aneurysm, Vascular Malformation, and SAH MRA Head MRA head is a noninvasive examination commonly used for treated aneurysm surveillance. This examination can be obtained without IV contrast using time-of-flight imaging, with IV contrast to improve flow-related artifacts occasionally encountered in aneurysms, or a combination of both. In the setting of coiled aneurysms, a meta-analysis found similar performance of both noncontrast and contrast-enhanced examinations with sensitivities of 86% for both time-of-flight and contrast-enhanced MRA, as well as specificities of 84% and 89%, respectively [58]. MRA head was also compared directly with catheter-directed angiography and found to result in substantial agreement (kappa 0.73) regarding treatment recommendations between the 2 examinations [59]. Treatment with stents or flow diverters results in challenges in MRA intraluminal evaluation of the stent. Contrast-enhanced MRA outperforms time-of-flight MRA in the evaluation of a treated aneurysm and parent vessel patency with indwelling stent; however, intraluminal detail is limited with both techniques [60]. Newer endovascular devices demonstrate magnetic susceptibility and Faraday cage effects, which limits MRA head utility in assessing for aneurysm thrombosis or parent vessel patency when compared with conventional arteriography [61-63].


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. MRA Neck There is no relevant literature to support the use of MRA neck in the surveillance of known, treated cerebral aneurysm.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. MRI Head Perfusion There is no relevant literature to support the use of MRI head perfusion in the surveillance of known, treated cerebral aneurysm.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. MRI Head There is no relevant literature to support the use of MRI head in the surveillance of known, treated cerebral aneurysm.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. MRV Head There is no relevant literature to support the use of MRV head in the surveillance of known, treated cerebral aneurysm.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. US Duplex Doppler Carotid Artery There is no relevant literature to support the use of carotid artery US duplex Doppler in the surveillance of known, treated cerebral aneurysm.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. US Duplex Doppler Transcranial There is no relevant literature to support the use of TCD in the surveillance of known, treated cerebral aneurysm.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. CT Head Perfusion There is no relevant literature to support the use of CT head perfusion in the screening of patients at high risk for cerebral aneurysm.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. CVD-Aneurysm, Vascular Malformation, and SAH CT Head There is no relevant literature to support the use of CT head in the screening of patients at high risk for cerebral aneurysm.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. CTA Head CTA head is a fast, noninvasive study to evaluate the intracranial vasculature. CTA head has been shown to be >90% sensitive and specific in the evaluation for aneurysms [4,10,13-18]. However, CTA head sensitivity for detecting an aneurysm decreases for both aneurysms <3 mm in size [4,10,13,15,17,19] and aneurysms occurring adjacent to an osseous structure [19].


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. CTA Neck There is no relevant literature to support the use of CTA neck in the screening of patients at high risk for cerebral aneurysm.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. CTV Head There is no relevant literature to support the use of CTV head in the screening of patients at high risk for cerebral aneurysm.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. MRA Head MRA head is an ideal candidate for screening high-risk populations for cerebral aneurysm due to its noninvasive nature and ability to obtain diagnostic information without IV contrast. The evaluation of intracranial aneurysm with MRA head demonstrated a pooled sensitivity of 95% and specificity of 89% in one meta-analysis, in which 45% of the 67 missed aneurysms were <3 mm in size, and another 45% were between 3 and 5 mm in size, 6% were between 5 and 10 mm in size, and 4% >10 mm in size [21]. Diagnostic accuracy is increased, including for aneurysms <5 mm in size, at 3T scanner strength [21,22]. Vessel loops and infundibular origins of vessels can lead to false-positives for aneurysm on MRA [23]. Contrast-enhanced MRA head has no relevant literature to support its use in the screening of patients at high risk for cerebral aneurysm.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. MRA Neck There is no relevant literature to support the use of MRA neck in the screening of patients at high risk for cerebral aneurysm.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. MRI Head Perfusion There is no relevant literature to support the use of MRI head perfusion in the screening of patients at high risk for cerebral aneurysm.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. MRI Head There is no relevant literature to support the use of MRI head in the screening of patients at high risk for cerebral aneurysm.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. MRV Head There is no relevant literature to support the use of MRV head in the screening of patients at high risk for cerebral aneurysm.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. US Duplex Doppler Carotid Artery There is no relevant literature to support the use of carotid artery US duplex Doppler in the screening of patients at high risk for cerebral aneurysm.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. US Duplex Doppler Transcranial There is no relevant literature to support the use of TCD in the screening of patients at high risk for cerebral aneurysm.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. Variant 6: Known high-flow vascular malformation (AVM/AVF). Surveillance monitoring. Intracranial high-flow vascular malformations include arteriovenous malformations (AVMs) and arteriovenous fistulas (AVFs). Both lesions are defined by an abnormal connection between the relatively high-pressure arterial system and the low-pressure venous system resulting in a high-flow shunting of blood.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. AVMs are direct connections of artery to vein via abnormal dilated vascular channels without normal intermediary capillary bed. The abnormal dilated vascular channels are known as the nidus [74]. Although the true incidence of brain AVM is unknown, asymptomatic prevalence on MRI is estimated at 0.05% [74,75]. Between 10% and 20% of patients with hereditary hemorrhagic telangiectasia will have at least one AVM during their lifetime [74,76].


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. CVD-Aneurysm, Vascular Malformation, and SAH


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. Symptomatic brain AVMs present most commonly with hemorrhage or epilepsy [74]. The annual rupture risk of a brain AVM is 1.3% for previously unruptured AVM and up to 4.8% for previously ruptured lesions [74,77]. Imaging findings associated with higher hemorrhage risk include intranidal aneurysm, deep venous drainage, deep location, or venous outflow obstruction [74,78]. Treatment for AVMs include surgical resection, endovascular embolization, stereotactic radiosurgery, or medical management. The ARUBA (A Randomised trial of Unruptured Brain Arteriovenous Malformations) trial concluded medical management alone was superior to medical management with interventional therapy for the prevention of death or stroke in patients with unruptured brain AVMs [79]. However, the trial did not establish the benefit of interventional treatment of unruptured AVMs, which remains a debated issue. The optimal methods for surveillance of untreated AVMs is not well established in the literature. However, treated lesions usually require long-term follow-up, specifically lesions treated with radiosurgery or embolization.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. Intracranial dural AVF (dAVF) is an abnormal shunt between a dural artery and venous sinus or cortical vein. dAVFs demonstrate similar high-flow vascular shunting but lack the central nidus associated with AVM. Signs and symptoms of dAVF depend on the location, with posterior dural venous sinus lesion frequently presenting with pulsatile tinnitus or cavernous sinus lesions presenting with pain, proptosis, chemosis, and ophthalmoplegia [80]. Complications of high-grade dAVF include hemorrhage or nonhemorrhagic neurologic defects and are associated with retrograde cortical venous drainage [80-83]. Treatment via endovascular or microsurgical approach is usually indicated in high-grade dAVF with cortical venous drainage or symptomatic lesions. Observation can be utilized in lower-grade lesions with less risk of hemorrhagic or neurologic complications [80,83]. This variant covers the surveillance of both treated and untreated high-flow vascular malformations.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. Arteriography Cervicocerebral Cervicocerebral angiography remains the reference standard for imaging of cerebrovascular disease, including AVM and dAVF. Angiography demonstrates high spatial and temporal resolution of critical importance in the characterization of the intranidal aneurysm in AVM as well as potentially small arterial feeding vessels and venous drainage characteristics in both AVM and dAVF. Arteriography is critical in planning treatment in all high-flow intracranial vascular malformations. Specifically, an arteriogram of an AVM provides high-resolution imaging of the nidus; however, 2-D angiographic images may overestimate lesion volumes when compared with MRA or CTA [84]. The addition of 3-D rotational cerebral arteriography results in more precise AVM nidus volume measurement when compared with CT and MRI [85].


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. CT Head Perfusion There is no relevant literature to support the use of CT head perfusion in the surveillance of high-flow intracranial vascular malformations.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. CT Head Although larger AVMs can be visualized on CT head because of hyperattenuating prominent vascular structures [83] and the osseous landmarks can be useful in radiation therapy treatment planning [85], there is no relevant literature to support the use of CT head in the surveillance of high-flow intracranial vascular malformations.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. CTA Head Sensitivity of CTA head was shown to be 90% for the overall detection of AVMs, 100% for AVMs >3 cm, and 88% for associated flow-related aneurysms when compared with DSA [86]. For high-flow AVFs, CTA head demonstrated a sensitivity of 86% and specificity of 100% in patients with pulsatile tinnitus [87]. Indirect signs of cortical venous drainage, indicating higher-risk lesion for future complication, on CTA exhibited sensitivities between 96% for cortical venous dilatation and 62% for identification of a medullary or pial vein. Drawbacks to CTA for surveillance monitoring include the lack of temporal resolution to directly determine flow dynamics of complex vascular lesions.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. CTA Neck There is no relevant literature to support the use of CTA neck in the surveillance of high-flow intracranial vascular malformations. CTA neck may be useful for potential treatment planning, but preference will be individual or site specific.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. CTV Head There is no relevant literature to support the use of CTV head in the surveillance of high-flow intracranial vascular malformations.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. CVD-Aneurysm, Vascular Malformation, and SAH MRA Head MRA head is frequently used in surveillance of known high-flow vascular malformations. In the setting of AVM, time-of-flight and contrast-enhanced MRA offer good diagnostic accuracy but lack temporal resolution for hemodynamics and information regarding the small angioarchitecture [88]. Multiple 4-D MRA techniques are available to provide temporal resolution with trade-off in spatial resolution. Although 4-D MRA demonstrates good agreement with DSA [89-91], MRA has limited sensitivity for small nidus (<1 cm) or complete resolution after treatment [88,92].


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. For AVF, time-of-flight MRA demonstrates excellent intermodality agreement with DSA regarding the location of the fistula site and good agreement regarding the arterial feeding vessels and venous drainage [93]. Time-of-flight and contrast-enhanced MRA demonstrated slightly lower negative predictive values in the evaluation of signs of cortical venous reflux when compared with CTA [94]. There is good to excellent correlation of 4-D MRA techniques to DSA demonstrated in multiple studies [95-97].


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. MRA Neck There is no relevant literature to support the use of MRA neck in the surveillance of high-flow intracranial vascular malformations. MRA neck may be useful for potential treatment planning, but preference will be individual or site specific.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. MRI Head Perfusion MRI head perfusion demonstrates variable perfusion abnormalities in the evaluation of hemodynamic physiology of AVM [83]. Perfusion examinations, including arterial spin-labeled perfusion imaging, may have a role in the evaluation of improved perfusion from obliteration of AVMs after radiation therapy [98].


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. MRI Head High-flow intracranial vascular malformations can be identified on MRI head because of dilated vessels. In a study evaluating MRI and AVM, T2-weighted images demonstrated overall sensitivity of 89% and 100% for lesions >3 cm as well as low (29%) sensitivity for AVM-associated aneurysms [86]. MRI can also provide important information regarding the associated brain parenchyma including ischemia on diffusion-weighted imaging or gliosis on T2 and Fluid-attenuated inversion-recovery imaging [83].


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. MRV Head There is no relevant literature to support the use of MRV head in the surveillance of high-flow intracranial vascular malformations.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. US Duplex Doppler Carotid Artery There is no relevant literature to support the use of carotid artery US duplex Doppler in the surveillance of high- flow intracranial vascular malformations.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. US Duplex Doppler Transcranial There is no relevant literature to support the use of TCD in the surveillance of high-flow intracranial vascular malformations.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. Primary CNS vasculitis is a rare disorder with 2.4 cases per 1 million person-years [99,101]. Primary CNS vasculitis typically presents with headache, followed by encephalopathy and behavioral changes. Focal neurological deficit occurs in 20% to 30% of patients. Seizures and intracranial hemorrhage may also occur. The diagnosis of primary CNS vasculitis is challenging because of its nonspecific and varied symptoms. Diagnostic criteria for CNS vasculitis


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. CVD-Aneurysm, Vascular Malformation, and SAH proposed by Calabrese and Mallek in 1988 required diagnosis via histopathology or characteristic findings on DSA [102,103]. Although angiographic diagnosis continues to be accepted by some authors [104], other authors have proposed diagnostic criteria that do not accept diagnosis based on angiography and require histology from biopsy or autopsy [105]. With a strong clinical suspicion, brain imaging is important for supporting the diagnostic process and directing biopsy [99,106]. Imaging examinations with CNS vasculitis demonstrate numerous nonspecific findings, such as infarcts, white matter injury, mass lesions, meningeal enhancement, or hemorrhage. Characteristic vessel imaging findings, though not always present on histologically proven cases, include multifocal stenosis and dilatation of the intracranial vasculature as well as characteristic pattern of vessel wall inflammation [107]. Many of the imaging features overlap with other cerebrovascular diseases, such as reversible cerebral vasoconstriction syndrome or atherosclerotic disease.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. Arteriography Cervicocerebral Cerebral arteriography has long been the standard in imaging diagnosis of CNS vasculitis due to its submillimeter resolution. However, cerebral angiography has low specificity for vasculitis given significant overlap of findings with other cerebrovascular diseases, such as atherosclerosis or reversible cerebral vasoconstriction syndrome, and limited sensitivity as the degree of vascular involvement can be below angiography resolution [99,107].


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. CT Head Perfusion There is no relevant literature to support the use of CT head perfusion in the initial imaging for suspected CNS vasculitis.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. CT Head There is no relevant literature to support the use of CT head in the initial imaging for suspected CNS vasculitis.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. CTA Head CTA head can characterize intracranial vessel luminal characteristics with limited resolution and evaluation of the distal small arteries. Findings of CNS vasculitis on CTA include multifocal vessel wall narrowing and dilatation with considerable overlap with other nonvasculitis cerebral vascular diseases and sensitivity is limited to resolution [99].


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. CTV Head There is no relevant literature to support the use of CTV head in the initial imaging for suspected CNS vasculitis.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. MRA Head MRA head offers a noninvasive and radiation free examination of the intracranial vessels. As stated above in the arteriography and CTA head sections, specificity of vascular luminal imaging is limited by considerable overlap with other cerebrovascular disease, such as atherosclerosis and reversible cerebral vasoconstriction syndrome, and sensitivity is limited to resolution as vasculitis can involve small distal arteries below native resolution of MRA [99]. In a recent retrospective comparison of time-of-flight MRA to DSA, time-of-flight MRA was abnormal in 81% of patients with angiographic findings of vasculitis and normal in 100% of patients with a normal angiogram. Although postcontrast imaging is utilized in vessel wall imaging MRI brain protocols and MRA is typically included in the imaging protocol, no relevant literature supports the use of postcontrast MRA in the initial imaging for suspected CNS vasculitis.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. MRI Head Perfusion There is no relevant literature to support the use of MRI head perfusion in the initial imaging for suspected CNS vasculitis.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. CVD-Aneurysm, Vascular Malformation, and SAH MRI Head MRI head is a useful examination in the evaluation of CNS vasculitis given its superior soft-tissue characteristics of the brain parenchyma and vessel walls. Multiple infarcts of variable ages are identified on MRI in up to 50% of patients with CNS vasculitis [99,101]. Other findings of primary CNS vasculitis include mass lesions, meningeal enhancement, and hemorrhage in 5%, 8%, and 9% of cases, respectively [99,101]. Progressive confluent white matter lesions, cortical and subcortical T2 lesions, multiple microhemorrhages, large single or multiple enhancing mass lesions, and enhancing small vessels/perivascular spaces are also seen [105]. Although parenchymal abnormalities on MRI have considerable overlap with other CNS diseases, sensitivity of a normal MRI for CNS vasculitis approaches 100% [99,101].


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. Recent advances in MRI intracranial vessel wall imaging shows promise in helping to differentiate CNS vasculitis from other cerebrovascular diseases as inflammatory changes of the vessel wall differ between conditions, whereas luminal stenoses and dilations can overlap [99,107-109]. In a recent retrospective study, the addition of contrast- enhanced MRI vessel wall imaging to luminal imaging (DSA, CTA, or MRA) increased radiological diagnostic accuracy to 89% when compared with 36% in luminal imaging alone in differentiating among nonocclusive cerebrovascular diseases. In this study the reference standard was the clinical diagnosis, so it remains to be determined whether these findings have any clinical value [107].


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. MRV Head There is no relevant literature to support the use of MRV head in the initial imaging for suspected CNS vasculitis.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. US Duplex Doppler Carotid Artery There is no relevant literature to support the use of carotid artery US duplex Doppler in the initial imaging for suspected CNS vasculitis.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. US Duplex Doppler Transcranial There is no relevant literature to support the use of TCD in the initial imaging for suspected CNS vasculitis.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. CVD-Aneurysm, Vascular Malformation, and SAH


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. Supporting Documents The evidence table, literature search, and appendix for this topic are available at https://acsearch.acr.org/list. The appendix includes the strength of evidence assessment and the final rating round tabulations for each recommendation.


Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. For additional information on the Appropriateness Criteria methodology and other supporting documents go to www.acr.org/ac.


Seizures Child

Seizures Child. Introduction/Background Epilepsy is defined as recurrent and unprovoked seizures and is one of the most common neurologic disorders. Status epilepticus is the most common neurologic emergency in children. The Centers for Disease Control and Prevention estimate that approximately 470,000 or 0.6% of children <17 years of age suffer from epilepsy, and approximately 50,000 new cases are being diagnosed in this age group every year [1].


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Seizures Child. OR Discussion of Procedures by Variant Variant 1: Neonatal seizures, age 0 to 29 days. Initial imaging. The incidence of neonatal seizures has been estimated to be 3 per 1,000 live births per year [5]. The incidence is higher in preterm infants (57 to 132 per 1,000 live births) [6]. In the neonatal age group, seizures from acute symptomatic causes are much more common than neonatal idiopathic epilepsies [7]. Studies demonstrate that an


Seizures Child

Seizures Child. Reprint requests to: publications@acr.org


Seizures Child

Seizures Child. MRI Head MRI is utilized to evaluate the extent and characteristics of parenchymal brain abnormalities in neonates with seizures [10]. Because hypoxic ischemic encephalopathy is the most common cause of neonatal seizures, diffusion- weighted imaging is the most sensitive sequence to detect an abnormality when performed at the appropriate time- interval [13]. In addition, MRI has the greatest sensitivity for detecting intracranial developmental abnormalities associated with seizures, including malformations of cortical development [14]. In a study of neonates with seizures, MRI showed findings in 11.9% of patients which were not apparent on cranial US, and in 39.8% of patients, MRI contributed to a diagnosis by providing information additional to cranial US [8]. Data are being accumulated establishing the prognostic value of MRI in neonates with seizures that demonstrates that the absence of major cerebral lesions on MRI is highly predictive of a normal neurological outcome [5,15]. There are potential risks associated with performing MRI in neonates who are in the intensive care unit, including the risks associated with transportation, positioning, and sedation of the patient in the setting of physiologic instability. The use of MRI- compatible incubators and small footprint MRI scanners can help with safer transportation and imaging of the patient.


Seizures Child

Seizures Child. CT Head CT has a limited but specific role in the evaluation of neonates with seizures. A noncontrast CT can be performed to detect hemorrhagic lesions in the encephalopathic infant with a history of birth trauma, low hematocrit, or coagulopathy. CT may help to define the extent of intracranial hemorrhage and is useful in quantifying and characterizing extra-axial collections, but CT is less sensitive than MRI for detecting hypoxic ischemic events and structural anomalies [7]. CT is helpful in identifying calcifications in a suspected intrauterine infection, any associated traumatic abnormalities, and in the identification of dural sinus thrombosis. CT is rapid, does not require sedation, and may provide better assessment of the brain compared with US in scenarios in which acute hemorrhage, stroke, or hydrocephalus is suspected.


Seizures Child

Seizures Child. FDG-PET/CT Brain There is no relevant literature to support the use of fluorine-18-2-fluoro-2-deoxy-D-glucose (FDG)-PET/CT in the workup of a neonate with seizures.


Seizures Child

Seizures Child. HMPAO SPECT or SPECT/CT Brain There is no relevant literature to support the use of Tc-99m hexamethylpropyleneamine oxime (HMPAO) single- photon emission computed tomography (SPECT) or SPECT/CT in the workup of a neonate with seizures.


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Seizures Child. US Head There is no relevant literature to support the use of US in the workup of a child with simple febrile seizures.


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Seizures Child. MRI Head MRI is not indicated in the workup of a child with simple febrile seizures. In a small prospective study of children with febrile seizures, definite abnormalities on brain MRI were found in 11.4% of children with simple febrile seizures, suggesting that brain abnormalities may lower seizure threshold in febrile children, but none of the imaging findings affected clinical management, hence it did not alter the recommendation that imaging is not indicated [17,18].


Seizures Child

Seizures Child. CT Head There is no relevant literature to support the use of CT in the workup of a child with simple febrile seizures.


Seizures Child

Seizures Child. FDG-PET/CT Brain There is no relevant literature to support the use of FDG-PET/CT in the workup of a child with simple febrile seizures.


Seizures Child

Seizures Child. HMPAO SPECT or SPECT/CT Brain There is no relevant literature to support the use of Tc-99m HMPAO SPECT or SPECT/CT in the workup of a child with simple febrile seizures.


Seizures Child

Seizures Child. Variant 3: Children 6 months to 5 years of age. Complex febrile seizures. Initial imaging. Complex febrile seizures account for about a third of all febrile seizures in infants and young children (6 months to 5 years of age). Complex febrile seizures are defined as seizures that last >15 minutes, recur more than once in 24 hours, or are focal [19,20]. Seizures in the setting of fever associated with underlying pathology, such as meningitis, encephalitis, or child abuse may present similarly, but are not considered complex febrile seizures by definition. There is a small increased risk for children with complex febrile seizures to develop epilepsy (ie, subsequent afebrile seizures) later in life, but other than an EEG and evaluation by a neurologist, imaging recommendations are the same as for simple febrile seizures [21].


Seizures Child

Seizures Child. US Head There is no relevant literature to support the use of US in the workup of a child with complex febrile seizures.


Seizures Child

Seizures Child. MRI Head In one study of children with febrile seizures recurrent within 24 hours, neuroimaging revealed benign findings in 7.4% of patients and did not add significant diagnostic or prognostic information [17]. Compared with children with simple febrile seizures, children with complex febrile seizures were found to be more likely to have an imaging abnormality (14.8% in patients with complex febrile seizures and 11.4% in patients with simple febrile seizures), but these findings did not alter the clinical management. In the absence of other neurological indications such as post ictal focal deficits, neuroimaging in complex febrile seizures is unnecessary [18]. Imaging may be performed in selected patients where complex febrile seizure is part of the differential diagnosis but etiologies such as meningitis, encephalitis, or trauma are being considered clinically as the underlying cause of the seizures [19,22]. MRI may also be indicated in children with febrile status epilepticus (seizure lasting >30 minutes) because increased association with imaging findings have been demonstrated in this patient population [23].


Seizures Child

Seizures Child. CT Head CT is usually not indicated in the workup of a child with complex febrile seizures. An analysis of six studies, including a total of 161 children with complex febrile seizures, demonstrated that head CT revealed no findings requiring intervention [22].


Seizures Child

Seizures Child. FDG-PET/CT Brain FDG-PET/CT is usually not indicated in the workup of a child with complex febrile seizures.


Seizures Child

Seizures Child. HMPAO SPECT or SPECT/CT Brain Tc-99m HMPAO SPECT or SPECT/CT is usually not indicated in the workup of a child with complex febrile seizures.


Seizures Child

Seizures Child. US Head There is no relevant literature to support the use of US in the workup of a child with post-traumatic seizures.


Seizures Child

Seizures Child. MRI Head A typical MRI examination is longer compared with CT and may not be suited for an intimal examination in the acute trauma setting. MRI may not be practically feasible compared with CT, depending on the overall clinical status of the child. However, MRI has high sensitivity for detecting intracranial hemorrhage, microhemorrhage, and parenchymal injury. Sequences such as susceptibility-weighted imaging and diffusion-weighted imaging are helpful in identifying patients with diffuse axonal injury [27], that is typically not apparent on CT examinations. At an interval after trauma, MRI can be useful in the evaluation of post-traumatic epilepsy, allowing for better identification and delineation of the sequela of prior traumatic brain injury, including gliosis, and volume loss.


Seizures Child

Seizures Child. CT Head If imaging is pursued, CT may be useful in the acute post-traumatic settings especially to identify acute intracranial hemorrhage or mass effect. In a study by Lee and Lui [25], CT identified 100% of the acutely treatable lesions in patients with mild trauma. In this study, although CT results were negative in 53% of patients, 7% of patients had lesions that required urgent surgical intervention.


Seizures Child

Seizures Child. FDG-PET/CT Brain There is no relevant literature to support the use of FDG-PET/CT in the acute workup of a child with post-traumatic seizures.


Seizures Child

Seizures Child. HMPAO SPECT or SPECT/CT Brain There is no relevant literature to support the use of Tc-99m HMPAO SPECT or SPECT/CT in the acute workup of a child with post-traumatic seizures.


Seizures Child

Seizures Child. Variant 5: Children 1 month to 17 years of age. Focal seizures, not including abusive head trauma. Initial imaging. Focal seizures are defined as those with onset, limited to one hemisphere of the brain, and include focal aware seizures (retained awareness) and focal impaired awareness seizures (formerly known as complex partial seizures) [3]. Positive yields from neuroimaging of patients with focal seizures are considerably higher when compared with those from imaging of patients with generalized seizures whose neurologic examination is normal [30,31]. Presence of any focal feature to the seizure was found to be independently associated with clinically relevant abnormalities on neuroimaging [32]. Young et al [33] noted a 50% positivity rate for CT when neurologic findings were focal as compared with 6% positive CT findings in patients without focal features. The frequency of recurrence of focal seizures was found to be up to 94%, which is considerably greater than that for generalized seizures (72%) [34].


Seizures Child

Seizures Child. Several seizure syndromes (eg, benign rolandic seizures, benign occipital epilepsy with classic EEG findings) are sufficiently characteristic to be diagnosed clinically or through specific EEG patterns and usually do not require imaging. Patients that may benefit from imaging include those who do not have typical clinical or EEG findings.


Seizures Child

Seizures Child. US Head There is no relevant literature to support the use of US in the workup of a child with focal seizures.


Seizures Child

Seizures Child. MRI Head Seizures can result from multiple intracranial pathologies including developmental abnormalities, hemorrhage, neoplasm, and gliosis. Aprahamian et al [35] found that approximately 4% of children with first-time afebrile seizures and focal manifestations had urgent intracranial pathology, most commonly infarction, hemorrhage, and thrombosis. MRI is more sensitive than CT in detection of brain abnormalities and therefore should be the primary


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Seizures Child. imaging in children with newly diagnosed seizures [36]. In a study by Jan et al [37], MRI demonstrated focal brain abnormalities in 55% of children with seizures, whereas CT was positive in only 18% of children. In the Aprahamian et al [35] study, 205 of 252 children who had a CT scan for their urgent imaging also had a subsequent MRI. Of these 205 children, 58 (28.2%) had abnormal findings on MRI, 29% of abnormal intracranial findings were not seen on initial CT in children with new-onset afebrile seizures with focal features [35]. In a study by Singh et al [38], MRI detected abnormalities not identified by CT in 47% of children who presented with new-onset status epilepticus. Additionally, MRI is superior to CT in identifying peri-ictal cortical abnormalities that might explain clinical deficits after acute seizure [39]. The epileptogenic lesion may not be detected using routine MRI protocols. Therefore, in these cases, an optimized epilepsy protocol with adequate spatial resolution and multiplanar reformatting is essential. A proper MRI investigation of patients with focal epilepsy requires the use of specific protocols, which are selected based on identification of the region of onset by clinical and EEG findings.


Seizures Child

Seizures Child. FDG-PET/CT Brain There is no relevant literature to support the use of FDG-PET/CT in initial management of focal seizures.


Seizures Child

Seizures Child. HMPAO SPECT or SPECT/CT Brain There is no relevant literature to support the use of ictal/interictal Tc-99m HMPAO SPECT or SPECT/CT in initial management of focal seizures.


Seizures Child

Seizures Child. Variant 6: Children 1 month to 17 years of age. Primary generalized seizure (neurologically normal). Initial imaging. The term generalized seizure, implies diffuse or generalized involvement of the brain on EEG or clinically [3]. Generalized seizures differ from a focal seizure with secondary generalization (now known as focal to bilateral tonic-clonic), which starts focally and then propagates to both hemispheres [3]. According to the most recent International League Against Epilepsy seizures classification, generalized seizures are categorized as motor and nonmotor (absence) seizures, but for the purpose of a diagnostic imaging workup, it is appropriate to classify them into generalized seizures in an otherwise neurologically normal child and generalized seizures in a neurologically abnormal child [3].


Seizures Child

Seizures Child. US Head There is no relevant literature to support the use of US in the workup of a neurologically normal child with generalized seizure.


Seizures Child

Seizures Child. MRI Head MRI is rarely indicated in evaluation of a neurologically normal child presenting with generalized seizures because the rate of positive intracranial findings in this group is low, given their genetic underpinnings. MRI is typically not indicated in patients with very typical forms of primary generalized epilepsy (eg, juvenile myoclonic epilepsy, childhood absence) or patients with characteristic clinical and EEG features and patients with adequate response to antiepileptic drugs. Sharma et al [31] studied 500 consecutive emergency department patients presenting with a first afebrile seizure. They defined two clinically significant high-risk indicators of abnormal neuroimaging: 1) presence of predisposing condition, and 2) focal seizure. Only 2% of low-risk patients had abnormal imaging findings on MRI.


Seizures Child

Seizures Child. CT Head CT is usually not indicated in the evaluation of an otherwise neurologically normal child with a generalized seizure. The frequency of positive CT findings in patients with idiopathic generalized seizures in children with normal neurologic examination and negative EEG has been estimated to be 2.5% [41,42].


Seizures Child

Seizures Child. FDG-PET/CT Brain There is no relevant literature to support the use of FDG-PET/CT in the workup of a neurologically normal child with generalized seizure.


Seizures Child

Seizures Child. HMPAO SPECT or SPECT/CT Brain There is no relevant literature to support the use of Tc-99m HMPAO SPECT/CT in the workup of a neurologically normal child with generalized seizure.


Seizures Child

Seizures Child. US Head There is no relevant literature to support the use of US in the workup of a child with generalized seizure and abnormal neurological findings.


Seizures Child

Seizures Child. MRI Head Patients with generalized seizures and abnormal neurologic findings can significantly benefit from MRI. MRI offers higher soft-tissue contrast than CT and provides additional information regarding brain anatomy.


Seizures Child

Seizures Child. CT Head CT has a limited role in the evaluation of a child with generalized seizures and abnormal neurological examination. Young et al [33] reported only 6% of CT examinations were positive for generalized seizures in contrast to nearly 50% positivity in focal epilepsy. CT may have an advantage over MRI in only uncommon situations of children with unstable clinical status with generalized seizures and abnormal neurological examination. In these cases, CT may provide initial diagnostic information that helps to guide early therapeutic decisions [44].


Seizures Child

Seizures Child. FDG-PET/CT Brain There is no relevant literature to support the use of FDG-PET/CT in the workup of a child with generalized seizure and abnormal neurological findings.


Seizures Child

Seizures Child. HMPAO SPECT or SPECT/CT Brain There is no relevant literature to support the use of Tc-99m HMPAO SPECT or SPECT/CT in the workup of a child with generalized seizure and abnormal neurological findings.


Seizures Child

Seizures Child. Variant 8: Children 1 month to 17 years of age. Intractable seizures or refractory epilepsy. Refractory seizures define a small percentage of patients with seizures or epilepsy. In these patients, the use of both anatomical and functional imaging modalities is needed in selected cases, and some of these cases are potentially treatable by surgical intervention.


Seizures Child

Seizures Child. Anatomic imaging with MRI may assist in determining the underlying pathology and help assess anatomical changes associated with seizure activity. Functional imaging, using MRI, PET, or SPECT, may depict seizure foci that are occult by anatomic imaging and may help guide a safe and effective surgical outcome.


Seizures Child

Seizures Child. US Head US is not useful in the workup of a child with intractable seizures or refractory epilepsy.


Seizures Child

Seizures Child. MRI Head MRI is considered the most sensitive and specific anatomic imaging technique in the evaluation of patients with intractable seizures and should be performed using dedicated epilepsy protocols with 3T scanners whenever possible. This includes, but is not limited to, a T1-weighted volumetric acquisition (3-D) with isotropic voxel size of 1 mm as well as images optimized for the evaluation of hippocampal pathology that include high-resolution thin coronal slices. Studies have shown that in this clinical scenario, MRI has a sensitivity of 84% with specificity of 70%, whereas the sensitivity of CT is approximately 62% [45]. MRI is particularly useful in the evaluation of mesial temporal sclerosis and cortical abnormalities that may be the cause of refractory seizures [46,47]. The data are limited on the additional value of specialized MRI sequences, such as diffusion tensor imaging, which may help to improve specificity in localization of the epileptogenic lesion in cases where conventional structural MRI is


Seizures Child

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Seizures Child. Seizures-Child


Seizures Child

Seizures Child. CT Head CT has lower sensitivity compared with MRI in localization and characterization of a potential epileptogenic focus. Available data indicate that the diagnostic yield of CT in evaluation of a child presenting with a breakthrough seizure in the setting of known refractory epilepsy is also very low. Allen et al [50] showed that in a cohort of 124 children presenting with breakthrough seizures, almost 17% underwent CT scans and none of them demonstrated acute findings.


Seizures Child

Seizures Child. FDG-PET/CT Brain Functional imaging is most utilized for refined evaluation when surgical intervention is contemplated or when structural imaging with MRI is normal or shows nonspecific findings [36]. A study by Leach et al [51] showed that MRI failed to demonstrate findings that would allow guidance for surgery in up to 58% of patients with surgically proven focal cortical dysplasia, supporting the need for a multimodality approach and underscoring the importance of functional studies in preoperative surgical planning. FDG-PET/CT has been shown to improve lesion detection and can be a helpful modality when anatomic imaging (CT and MRI) is normal or in cases when multiple structural abnormalities are present. In a study by Kim et al [52], interictal FDG-PET was shown to have statistically significantly better detection power (P = .013) than MRI, with the higher percentage of cases with MRI discordance and PET localization than in reverse. Menon et al [53] showed that approximately 31% of patients with drug- resistant epilepsy were selected for respective surgery based on FDG-PET results. Sensitivity of FDG-PET in localization of an epileptogenic lesion has been shown to be 63% to 67% [45,54,55]. At the same time, specificity of FDG-PET in localization-related epilepsy with nonlesional MRI reaches 94% [45,55]. There are limited data that show FDG-PET as having prognostic value regarding the outcome of epilepsy surgery in refractory focal epilepsy [56]. In a cohort of patients with temporal lobe epilepsy, surgical outcomes for PET-positive and MRI-negative patients did not differ from outcomes of patients with mesial temporal sclerosis demonstrated on MRI [57]. FDG- PET has been shown to be useful in evaluating residual foci of seizure activity in patients who have undergone unsuccessful surgical intervention [58]. More recently, FDG-PET and MRI coregistration has also been shown to improve lesion detection. This can be performed by fusion of the PET images with separately acquired MRI or as single-setting PET, not MRI acquisition [59,60].


Seizures Child

Seizures Child. 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.


Seizures Child

Seizures Child. For additional information on the Appropriateness Criteria methodology and other supporting documents go to www.acr.org/ac.


Pretreatment Evaluation and Follow Up of Endometrial Cancer. Introduction/Background Accurate pretreatment evaluation of endometrial carcinoma (EC) may optimize therapy, particularly with regard to choosing the type of surgery. Preoperative imaging of EC can define the extent of disease and indicate the need for subspecialist referral in the presence of deep myometrial invasion, cervical extension, suspected lymphadenopathy or if high-grade endometrioid carcinoma or high-risk histology (such as papillary serous or clear cell carcinoma) is found at the time of biopsy. Cross-sectional imaging techniques play a vital role in the pretreatment assessment of uterine cancers and should be viewed as complementary modalities for surgical evaluation of these patients. The depth of myometrial invasion, cervical stromal invasion, local regional invasion of pelvic structures, and distant metastasis can be readily detected at cross-sectional imaging. Although ultrasound (US) remains the imaging modality of choice to screen women who have suspected EC, state-of-the-art dynamic contrast-enhanced and diffusion-weighted imaging (DWI) MR techniques are better suited to preoperatively stage, identify recurrence, and assess local treatment response in women with EC.