Different Mismatch Concepts for Magnetic Resonance Imaging–Guided Thrombolysis in Unknown Onset Stroke

OBJECTIVE: To explore the prevalence of the perfusion-weighted imaging (PWI)-diffusion-weighted imaging (DWI) mismatch and response to intravenous thrombolysis in the WAKE-UP trial. METHODS: We performed a prespecified post hoc analysis of ischemic stroke patients screened for DWI-fluid-attenuated inversion recovery (FLAIR) mismatch in WAKE-UP who underwent PWI. We defined PWI-DWI mismatch as ischemic core volume 10ml, and mismatch ratio > 1.2. Primary efficacy end point was a modified Rankin Scale score of 0-1 at 90 days, adjusted for age and symptom severity. RESULTS: Of 1,362 magnetic resonance imaging-screened patients, 431 underwent PWI. Of these, 57 (13%) had a double mismatch, 151 (35%) only a DWI-FLAIR mismatch, and 54 (13%) only a PWI-DWI mismatch. DWI-FLAIR mismatch was more prevalent than PWI-DWI mismatch (48%, 95% confidence interval [CI] = 43-53% vs 26%, 95% CI = 22-30%; p