Intravenous Thrombolysis Based on Diffusion-Weighted Imaging and Fluid-Attenuated Inversion Recovery Mismatch in Acute Stroke Patients with Unknown Onset Time

Abstract

Background and Purpose: Patients with unknown onset time would be able to receive intravenous thrombolysis when showing diffusion-weighted imaging (DWI)/fluid-attenuated inversion recovery (FLAIR) mismatch. Methods: Consecutive acute stroke patients with unknown onset time were prospectively enrolled. We defined patients as having unknown onset time when the last known normal time (LNT) was not consistent with the first found abnormal time (FAT). Only patients with anterior-circulation stroke and presence of arterial lesion were enrolled. Intravenous thrombolysis was conducted within 3 h from FAT if the patient showed DWI/FLAIR mismatch. Results: From June 2009 to May 2010, 10 patients [median age, 84 years (interquartile range, IQR, 64–90); National Institutes of Health Stroke Scale (NIHSS) score, 14 (IQR, 9–19)] were enrolled. Subjects included 4 patients who developed stroke during sleep, 5 with disturbance of consciousness, and 1 with aphasia. Median interval between LNT and thrombolysis was 5.6 h (IQR, 4.5–9.8) and median interval between FAT and thrombolysis was 2.5 h (IQR, 2.1–2.8). Three patients had internal carotid artery occlusion, 5 had M1 occlusion, and 2 had M2 occlusion. Early recanalization within 24 h was seen in 7 patients (complete recanalization, n = 4; partial recanalization, n = 3). No patients experienced symptomatic cerebral hemorrhage within 48 h. At day 7, 5 patients showed dramatic recovery (defined as ≧10-point reduction in total NIHSS score or score of 0 or 1). At 3 months, favorable outcome (modified Rankin scale score, 0–2) was seen in 4 patients. Conclusion: Acute stroke patients with DWI/FLAIR mismatch may be able to safely receive intravenous thrombolysis.