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

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... 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 (PϽ0.001), vascular territory determination (Pϭ0.003), vessel occlusion identification (PϽ0.001), TOAST classification (Pϭ0.039), and Oxfordshire Community Stroke Project classification (PϽ0.001) 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. (Stroke. 2002;33:959-966.)