Serial Computed Tomography Perfusion and Diffusion Imaging After Complete Recanalization in Large‐Vessel Occlusion

Background Infarct evolution on diffusion‐weighted imaging (DWI) after complete recanalization and its relationships to computed tomography perfusion core and outcome remain uncertain. Methods From a multicenter registry (2014–2024), we identified 189 patients with anterior‐circulation large‐vessel occlusion, modified Thrombolysis in Cerebral Infarction grade 3 recanalization, prethrombectomy computed tomography perfusion, immediate DWI within 24 hours, and delayed DWI at 24 to 168 hours. Robust linear regression identified predictors of DWI volume change; logistic regression assessed 90‐day modified Rankin Scale scores of 0 to 2. Results DWI volume increased in 162 of 189 patients (85.7%), from a median of 4.8 mL (interquartile range, 1.1–16.4) immediately after thrombectomy to 11.7 mL (interquartile range, 3.8–40.2) on delayed imaging; the median change was 4.4 mL (interquartile range, 0.7–14.8). Baseline computed tomography perfusion core was method‐sensitively associated with greater change in the full model without immediate DWI (β=0.154 [heteroscedasticity‐consistent 95% CI, −0.024 to 0.332]; P =0.09; bootstrap 95% CI, 0.018–0.336; P =0.014) and attenuated after immediate DWI adjustment (β=0.100; P =0.22; bootstrap P =0.077). Each decile increase in volume change was associated with lower odds of functional independence (adjusted odds ratio, 0.81 [95% CI, 0.68–0.97]; P =0.021). Delayed DWI showed the best outcome discrimination. Conclusions DWI‐defined infarct volume increased after complete recanalization and was associated with functional outcome. The core association was method‐sensitive and attenuated after accounting for immediate DWI, supporting a possible mediated rather than independent pathway.