Background: Rapid and easy clinical assessments for volumes of infarction and perfusion mis-

Background and Purpose-The purpose of this study was to determine whether acute diffusion-weighted imaging (DWI) and mean transit time (MTT) lesion volumes and presenting National Institutes of Health Stroke Scale (NIHSS) can identify patients with acute ischemic stroke who will have a high probability of good and poor outcomes. Methods-Fifty-four patients with acute ischemic stroke who had MRI within 9 hours of symptom onset and 3-month follow-up with modified Rankin scale were evaluated. Acute DWI and MTT lesion volumes and baseline NIHSS scores were calculated. Clinical outcomes were considered good if the modified Rankin Scale was 0 to 2. Results-The 33 of 54 (61%) patients with good outcomes had significantly smaller DWI lesion volumes (Pϭ0.0001), smaller MTT lesion volumes (PϽ0.0001), and lower NIHSS scores (PϽ0.0001) compared with those with poor outcomes. Receiver operating characteristic curves for DWI, MTT, and NIHSS relative to poor outcome had areas under the curve of 0.889, 0.854, and 0.930, respectively, which were not significantly different. DWI and MTT lesion volumes predicted outcome better than mismatch volume or percentage mismatch. All patients with a DWI volume Ͼ72 mL (13 of 54) and an NIHSS score Ͼ20 (6 of 54) had poor outcomes. All patients with an MTT volume of Ͻ47 mL (16 of 54) and an NIHSS score Ͻ8 (17 of 54) had good outcomes. Combining clinical and imaging thresholds improved prognostic yield (70%) over clinical (43%) or imaging (54%) thresholds alone (Pϭ0.01). Conclusions-Combining quantitative DWI and MTT with NIHSS predicts good and poor outcomes with high probability and is superior to NIHSS alone. (Stroke. 2010;41:1728-1735.)

Persistence of mismatch after 9 hours is common and occurs most often in patients with PAO.

Background and Purpose-Our purpose was to determine (1) the correlation between quantitative CT and MR measurements of infarct core, penumbra, and mismatch; and (2) whether the difference between these measurements would alter patient selection for stroke clinical trials. Methods-We studied 45 patients with acute middle cerebral artery stroke imaged a mean of 3.