Biomedical subjects
Publications and source records attributed to Alan Z Segal.
A 61-year-old man presenting with transient global aphasia and chronic major depression was found to have a giant high flow dural arteriovenous fistula of the superior sagittal sinus. EEG and SPECT scan showed left frontoparietal dysfunction. This resolved after fistula embolization, as did the patient's neuropsychiatric complaints.
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BACKGROUND AND PURPOSE: In CT angiographic and perfusion imaging (CTA/CTP), rapid CT scanning is performed during the brief steady state administration of a contrast bolus, creating both vascular phase images of the major intracranial vessels and perfused blood volume-weighted parenchymal phase images of the entire brain. We assessed the added clinical value of the data provided by CTA/CTP over that of clinical examination and noncontrast CT (NCCT) alone. METHODS: NCCT and CTA/CTP imaging was performed in 40 patients presenting with an acute stroke. Short clinical vignettes were retrospectively prepared. After concurrent review of the vignettes and NCCT, a stroke neurologist rated infarct location, vascular territory, vessel(s) occluded, and Trial of Org 10172 in Acute Stroke Treatment (TOAST) and Oxfordshire Community Stroke Project classifications. The ratings were repeated after serial review of each of the CTA/CTP components: (1) axial CTA source images; (2) CTP whole brain blood volume-weighted source images; and (3) maximum-intensity projection 3-dimensional reformatted images. The sequential ratings for each case were compared with the final discharge assessment. RESULTS: Compared with the initial review after NCCT, CTA/CTP improved the overall accuracy of infarct localization (P<0.001), vascular territory determination (P=0.003), vessel occlusion identification (P<0.001), TOAST classification (P=0.039), and Oxfordshire Community Stroke Project classification (P<0.001) by 40%, 28%, 38%, 18%, and 32%, respectively. CONCLUSIONS: Admission CTA/CTP imaging significantly improves accuracy, over that of initial clinical assessment and NCCT imaging alone, in the determination of infarct localization, site of vascular occlusion, and Oxfordshire classification in acute stroke patients.
BACKGROUND AND PURPOSE: The risk of stroke after a transient ischemic attack (TIA) is high. Appropriately directed therapies may reduce this risk. However, sensitive means of detecting the presence of subtle neuronal ischemia are lacking. We investigated the potential use of quantitative diffusion-weighted (DW) MR imaging in the detection of deficits produced by transient cerebral ischemia. METHODS: Twenty-eight patients who came to the stroke service from the emergency room of a tertiary teaching hospital with the final diagnosis of transient cerebral ischemia underwent conventional MR imaging, MR angiography, and DW MR imaging within 24 hours of presentation. Fifteen patients had normal conventional DW images confirmed by a staff neuroradiologist and neurologist. For these patients, absolute quantitative diffusion values were subsequently calculated for the clinically relevant brain region and were compared with the values calculated for the corresponding contralateral unaffected brain region. Thirteen patients had conventional DW images positive for lesions and were not studied. RESULTS: Quantitative DW imaging enabled detection of abnormal decreases (9-26%, P <.05) in the diffusion constant in brain regions suspected to be clinically involved by ischemia, when compared with the contralateral clinically unaffected brain tissue as well as with two other internal controls. CONCLUSION: Quantitative DW imaging depicts diffusion deficit in patients with TIA. Quantitative DW imaging may have better sensitivity compared with conventional DW imaging in detecting transient cerebral ischemia.