Abstract
BACKGROUND AND PURPOSE: We hypothesize that reversal in diffusion-weighted imaging (DWI) volume at 24 hours predicts favorable clinical outcome only if accompanied by immediate reperfusion. Our aim was to quantify the immediate DWI and mean transit time changes at 2 and 24 hours after intravenous tissue-type plasminogen activator to evaluate the effect of reperfusion and DWI change on outcome. METHODS: Patients were selected from the Lesion Evolution in Stroke and Ischemia On Neuroimaging Project if they had an acute MRI with evaluable DWI and perfusion-weighted imaging, were treated with standard intravenous tissue-type plasminogen activator, had post-thrombolysis MRI with evaluable DWI and perfusion-weighted imaging at 2 and 24 hours and had follow-up fluid attenuated inversion recovery MRI at discharge through 90 days. A reader measured the DWI, mean transit time, and fluid attenuated inversion recovery volumes using a validated technique. A vascular neurologist scored the National Institutes of Health Stroke Scale at admit, 2, and 24 hours and the modified Rankin Scale at discharge, 5, 30, and 90 days. Favorable clinical outcome was defined as modified Rankin Scale of 0 or 1. RESULTS: Seventy-one patients met the study criteria with mean (±SD) age of 71.6 (±16.4) years, 58% women, median admit National Institutes of Health Stroke Scale 9 (interquartile range, 4-18), median onset to triage 45 minutes (30-65), and median first MRI to intravenous tissue-type plasminogen activator 47 minutes (39-59). In binary multiple logistic regression analysis, younger age (odds ratio, 1.165; P=0.014; 95% confidence interval [CI], 1.031-1.316), lower admit National Institutes of Health Stroke Scale (odds ratio, 1.221; P=0.012; 95% confidence interval, 1.045-1.427), decrease in mean transit time volume at 2 hours (odds ratio, 1.021; P=0.031; 95% confidence interval, 1.002-1.040), and decrease in DWI volume at 24 hours (odds ratio, 1.173; P=0.027; 95% confidence interval, 1.018-1.351) were significant predictors of favorable clinical outcome. CONCLUSIONS: Reversal of the DWI volume at 24 hours because of immediate reperfusion in patients post thrombolysis is predictive of favorable clinical outcome.