Non Traumatic Emergent Neuroradiology

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Nontraumatic Emergent Neuroradiology

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<p>AJR Integrative ImagingLIFELONG LEARNING FOR RADIOLOGY</p> <p>Nontraumatic Emergent Neuroradiology: Review and Self-Assessment ModuleYoshimi Anzai1 and Basavaraj Ghodke2</p> <p>AbstrAct ObjectiveThe educational objectives for this case-based self-assessment module on imaging of nontraumatic emergent neuroradiology are to use case examples to teach the imaging features of CT and MRI of emergent neuroradiologic diagnoses and to improve the readers understanding of the pathophysiology and clinical management of each clinical scenario. Imaging plays a critical role in assessing patients with acute neurologic symptoms. CT is quick and easy to perform in an emergency setting and is often the technique of choice for any neurologic emergency situations. Clinical correlation is crucial for accurate diagnosis and triaging patients for further evaluation. Persistent or progressive neurologic symptoms despite negative CT should prompt other imaging studies.</p> <p>EDUcAtIONAL ObJEctIVEsBy completing this educational activity, the participant will: A. Exercise, self-assess, and improve his or her understanding of the imaging features of nontraumatic emergent neuroradiology diagnoses. B. Exercise, self-assess, and improve his or her understanding of the clinical features of nontraumatic emergent neuroradiology diagnoses.</p> <p>rEcOMMENDED rEADING1. Provenzale JM. Centennial dissertation. Honoring Arthur W. Goodspeed, MD and James B. Bullitt, MD. CT and MR imaging and nontraumatic neurologic emergencies. AJR 2000; 174:289299 2. Wintermark M, Albers GW, Alexandrov AV et al. Acute , stroke imaging research roadmap. Stroke 2008; 39: 16211628 3. Beauchamp NJ Jr, Bryan RN. Acute cerebral ishemic infarction: a pathophysiologic review and radiologic perspective. AJR 1998; 171:7384 4. Zuccoli G, Gallucci M, Capellades J, et al. Wernicke encephalopathy: MR findings at clinical presentation in twenty-six alcoholic and nonalcoholic patients. AJNR 2007; 28:13281331</p> <p>conclusionAt the end of this self-assessment module, readers will be able to generate a concise list of differential diagnoses for imaging findings that often are encountered in patients with nontraumatic neurologic emergency.</p> <p>INtrODUctIONThis self-assessment module on nontraumatic emergent neuroradiology diagnoses has an educational component and a self-assessment component. The educational component consists of six case scenarios that the participant should work through and four recommended articles that may provide additional information and perspective. The self-assessment component consists of 19 multiple-choice questions with solutions. All of these materials are available on the ARRS Website (www.arrs.org). To claim CME and SAM credit, each participant must enter his or her responses to the questions online.</p> <p>INstrUctIONs1. Complete the educational and self-assessment components. 2. Visit www.arrs.org and select Publications/Journals/ SAM Articles from the left-hand menu bar. 3. Using your member login, order the online SAM as directed. 4. Follow the online instructions for entering your responses to the self-assessment questions and complete the test by answering the questions online.</p> <p>Keywords: brain imaging, case-based learning, emergency, neuroradiology, self-assessment DOI:10.2214/AJR.07.7042 Received September 7, 2007; accepted after revision January 30, 2008.1 Department of Radiology, Division of Neuroradiology, University of Washington, 1959 NE Pacific St., NW 011, Box 357115, Seattle, WA 98195-7115. Address correspondence to Y. Anzai (anzai@u.washington.edu). 2</p> <p>Department of Radiology, Harborview Medical Center, Seattle, WA.</p> <p>AJR 2008;191:S1S17 0361803X/08/1913S1 American Roentgen Ray Society</p> <p>AJR:191, September 2008</p> <p>S1</p> <p>Anzai and Ghodke</p> <p>scenario 1Clinical History A 32-year-old man presented to the emergency department complaining of headache and general fatigue. He was diagnosed with a viral syndrome and discharged with symptomatic treatment. Two weeks later he presented to the emergency department with severe headache and confusion. He was afebrile but his mental status had changed since his previous emergency department visit. A working diagnosis of bacterial meningitis was considered. The patient denied any focal weakness or sensory or visual changes. Unenhanced CT (Fig. 1A) and CT angiography (Fig. 1B) of the head were performed. The patient also underwent cerebral angiography (Figs. 1C and 1D). Description of Images Unenhanced CT of the head showed a large right frontal intraparenchymal hematoma with surrounding edema, likely representing a subacute intracranial hematoma. CT</p> <p>angiography did not reveal any cerebral aneurysms, arteriovenous malformation, or enhancing focus as possible causes of a hematoma. Cerebral angiography showed irregularity of small- to medium-sized vessels and a beaded appearance, consistent with vasculitis. The patient admitted that he smoked marijuana almost daily and had a long history of amphetamine use.</p> <p>QUEstION 2Which one of the following is NOT associated with vasculitis? A. B. C. D. E. Polyarteritis nodosa. Tuberculosis. Systemic lupus erythematosus. Drugs (amphetamine, cocaine). Marfan syndrome.</p> <p>QUEstION 3 QUEstION 1Which of the following is the preferred diagnosis? A. B. C. D. E. Arteriovenous malformation. Hypertensive hemorrhage. Hemorrhagic tumor or metastasis. Vasculitis. Amyloid angiopathy. What is the most definitive test for diagnosing CNS vasculitis? A. B. C. D. E. CT angiography with 3D volume rendering. Cerebral angiography. Biopsy. MR angiography. Transcranial Doppler sonography.</p> <p>c</p> <p>A</p> <p>b</p> <p>D</p> <p>Fig. 132-year-old man with headache and general fatigue who was diagnosed with viral syndrome and discharged but returned with severe headache and confusion. A and B, Unenhanced CT (A) and CT angiography (B) of head were performed. Unenhanced CT shows large right frontal intraparenchymal hematoma and surrounding edema (arrow, A), likely representing subacute intracranial hematoma. CT angiography does not reveal any cerebral aneurysms, arteriovenous malformation, or enhancing focus as possible cause of hematoma. C and D, Cerebral angiography shows irregularity of small- to medium-sized vessels (arrows, D) and beaded appearance, consistent with vasculitis. Patient admitted that he smokes marijuana almost daily and has long history of amphetamine use.</p> <p>S2</p> <p>AJR:191, September 2008</p> <p>Nontraumatic Emergent Neuroradiology</p> <p>Solution to Question 1 Arteriovenous malformation (AVM) is not an unusual cause of intracranial hematoma for the young patient in this case. Patients with AVM often present with acute intracranial hemorrhage or ischemic symptoms due to steal phenomenon. CT angiography often reveals a tangle of markedly dilated arteries and veins with a nidus of AVM. If the AVM is small, it may not be visualized or diagnosed correctly with CT angiography. In this setting, cerebral angiography is the most definitive test. However, cerebral angiography in this patient did not show early venous filling or an abnormal tangle of blood vessels to indicate AVM. Therefore, option A is not the best response. Acute intracranial hematoma can have a number of causes. The most common cause is hypertensive hemorrhage. Hypertensive hemorrhages, which originate from terminal small vessels, are often centered at the basal ganglia, particularly the putamen and the external capsule; the thalamus; the pons; and occasionally, the cerebellum. Lobar hemorrhage can be seen in a setting of hypertension ( 12%), but it is rare. Hypertensive hemorrhage is much more common in older patients. Option B is not the correct response. Certain types of brain tumors are often associated with intracranial hemorrhage. These are often aggressive tumors, such as glioblastoma multiforme, or vascular tumors, such as metastases from renal cell carcinoma or melanoma, but rarely papillary thyroid cancer and choriocarcinoma. Lung cancer and breast cancer are not considered vascular; however, the incidence of brain metastasis from lung and breast cancers is exceedingly higher than that of other vascular cancers. Thus, when all hemorrhagic brain metastases are reviewed, lung and breast remain the two top primary choices. Intracranial hemorrhage associated with brain tumor often has a focal area of enhancement and significant mass effect or vasogenic edema. Option C is not the best response. Vasculitis is one of the causes of intracranial hemorrhage and is more frequently seen in young patients. Vasculitis can present with acute hemorrhage or ischemic symptoms. Many causes of vasculitis affect small- to medium-sized vessels; therefore, CT angiography may not show an irregularity of the blood vessels as definitively as cerebral angiography. Cerebral angiography in Figures 1C and 1D shows a classic appearance of segmental narrowing and poststenotic dilatation involving multiple small- to medium-sized blood vessels, consistent with vasculitis. Option D is the best response. Amyloid angiopathy often causes a lobar intracranial hemorrhage centered at the deep white matter in the frontal or parietal lobes. Amyloid angiopathy is much more common in elderly patients and is rare in young patients. Cerebral angiography may not show any irregularity or narrowing. Amyloid angiopathy is often diagnosed after excluding other causes in elderly patients. Option E is not the best response. Solution to Question 2 The causes of vasculitis are often divided into infectious and noninfectious. Infectious causes include tuberculosis, fun-</p> <p>gal infection, bacterial vasculitis, and HIV vasculitis. The frequent causes of noninfectious vasculitis are immune-mediated vasculitis such as rheumatoid arthritis and systemic lupus erythematosus, and granulomatous disease, such as Wegeners granulomatosis and sarcoid, as well as giant cell arteritis (also called temporal arteritis). Drugs, particularly amphetamines and cocaine, are frequent causes of noninfectious vasculitis. An amphetamine causes inflammatory vasculitis with vascular wall necrosis and subsequent hemorrhage. The pathologic features of amphetamine-related vasculitis are similar to those of polyarteritis nodosa. This patient had taken amphetamines for several years. Cocaine, on the other hand, induces cerebral infarction or ischemia as well as hemorrhage by vasoconstrictive effect and increased platelet aggregation, rather than a vasculitis-type inflammation of the vessels [1]. Options A, B, C, and D are not the best responses. Marfan syndrome is an autosomal dominant disorder of the connective tissue characterized by disproportionally long limbs and tall stature. It affects the heart and aorta and causes aortic root dilatation, aortic regurgitation, and dissection. However, involvement of CNS vessels is unusual. Option E is the best response. Solution to Question 3 Because many cases of vasculitis affect small to mediumsized blood vessels, MR angiography is relatively insensitive for the diagnosis of CNS vasculitis. CT angiography is less accurate than cerebral angiography. Cerebral angiography is used as the gold standard for diagnosis at many institutions. When characteristic angiographic findings such as alternating areas of stenosis and dilatation or a beading appearance are observed in multiple vessels and multiple vascular beds, cerebral angiography is diagnostic. However, angiography can be normal in up to 40% of biopsy-proven cases. Thus, negative cerebral angiography does not completely exclude the diagnosis. Moreover, its specificity is not perfect. Intracranial atherosclerotic disease may show irregularity of multiple vessels, mimicking CNS vasculitis. Transcranial Doppler sonography is used to characterize the morphology of the superficial temporal artery as a screening tool for temporal arteritis. However, transcranial Doppler sonography is not suitable to evaluate arteries fully to diagnose CNS vasculitis. Options A, B, D, and E are not the best responses. Biopsy of CNS tissue would logically be considered the ultimate gold standard of diagnosis, but clearly the procedure is limited by several factors. It is highly invasive and carries certain risks. Successful biopsy requires a willing and experienced neurosurgeon, who may not be readily available. Sampling error could result in limited sensitivity. The site of biopsy should be tailored to the individual patient [2]. The biopsy of the superficial temporal artery is often performed in patients suspected of having giant cell vasculitis. The false-negative rate of biopsy for a diagnosis of vasculitis has been reported to be 16%, yielding a sensi-</p> <p>AJR:191, September 2008</p> <p>S3</p> <p>Anzai and Ghodke</p> <p>tivity of 84% [2]. Therefore, the most definitive test is biopsy of the blood vessels. Option C is the best response. Conclusion Vasculitis involving the CNS presents diagnostic challenges to clinicians as well as radiologists. There are many causes, including infection, autoimmune disease, drug ex-</p> <p>posure, radiation, and malignancies. Cerebral angiography is more sensitive than noninvasive vascular imaging (CT angiography or MR angiography), but it is invasive and has limited sensitivity and specificity. Treatment of noninfectious vasculitis is long-term, high-dose immunosuppression, which causes profound morbidity as a result of opportunistic infection or organ failures.</p> <p>scenario 2Clinical History A 19-year-old woman presented to an outside hospital with severe headache, nausea, vomiting, and photophobia. She had no significant medical history. Laboratory examinations were unremarkable. Her initial head CT scans (unenhanced and contrast-enhanced) are shown in Figures 2A and 2B. Description of Images Unenhanced CT of the head showed a focal area of low attenuation in the left temporal lobe and mild regional mass effect. The ventricles were normal in size with no shift of midline structures. No parenchymal hemorrhage was evident. The contrast-enhanced image showed the empty delta</p> <p>sign (Fig. 2B). Brain MRI, including sagittal T1-weighted imaging (Fig. 2C), diffusion-weighted imaging (Fig. 2D), and apparent diffusion coefficient (ADC) mapping (Fig. 2E) were also performed at the outside hospital. The sagittal T1-weighted image showed an isointense clot along the superior sagittal sinus that was of concern for superior sagittal sinus thrombosis. The diffusion-weighted image showed no areas of restricted diffusion or ADC map abnormality. The patients mental status deteriorated at the outside hospital and she was transferred to the emergency department of our hospital, at which time she was unresponsive and obtunded, and her pupils were dilated. CT of the head was</p> <p>QUEstION 5Which one of the following techniques is LEAST appropriate to confirm a diagnosis of venous sinus thrombosis? A. Rapid contrast-enhanced gradient-echo MRI with contrast-enhanced multiplanar imaging. B. MDCT angiography or venography. C. Brain MRI and phase-contrast MR venogra...</p>