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