As it can be challenging to visually rate diffusion-weighted imaging (DWI)–fluid-attenuated inversion recovery (FLAIR) mismatch, researchers sought to evaluate quantification of DWI and FLAIR to prognosticate DWI-FLAIR mismatch status in ischemic stroke.

• From the WAKE-UP trial (Efficacy and Safety of Magnetic Resonance Imaging-Based Thrombolysis in Wake-Up Stroke), relative DWI (rDWI SI) and FLAIR signal intensity (rFLAIR SI) were retrospectively studied in screened patients.

• In the rFLAIR and rDWI SI analysis, DWI-FLAIR mismatch was observed in 213/369 and 241/421 individuals, respectively.

• For predicting the DWI-FLAIR mismatch, the optimal mean rFLAIR SI cutoff was 1.09 and interquartile range rDWI SI cutoff was 0.47 with a sensitivity and specificity of 77% (95% CI, 71%–83%) and 67% (95% CI, 59%–74%), and 76% (95% CI, 70%–81%) and 72% (95% CI, 65%–79%), respectively.

• There appeared insufficient agreement between the quantitative and qualitative approach to advocate DWI or FLAIR quantification as alternative for visual rating.