Kara Jo Swafford, MD
Animal models and clinical studies show that partial or complete reversal of diffusion-weighted imaging (DWI) lesions occurs following reperfusion, including with intravenous thrombolysis. Endovascular thrombectomy (EVT) can also reduce infarct expansion and potentially reverse DWI lesions; however, further clinical studies are needed. Yoo et al. performed a retrospective analysis of patients with acute ischemic anterior circulation stroke receiving EVT who were prospectively enrolled in a multicenter registry. They determined the odds of DWI reversal after EVT, clinical outcomes, and independent predictors of DWI reversal.
Baseline (pre-EVT) and follow-up (post-EVT) DWI volumes were measured. If the follow-up DWI volume decreased from baseline, the DWI lesion was considered reversible. Onset-to-baseline DWI time for patients with and without DWI reversal was 277±214 versus 257±209 minutes (P=0.487). Mean onset-to-puncture time was 338±222 minutes. Time from baseline to follow-up DWI was 4.7±2.4 days. Of 404 patients, 63 (15.5%) had DWI reversal. Initial stroke severity based on the National Institutes of Health Stroke Scale (NIHSS) score was similar, but the score was lower in the DWI reversal group at 7 days. Patients with DWI reversal had better functional outcomes at 3 months.
Independent predictors of good functional outcomes included young age, lower initial NIHSS score, lower baseline DWI volume, shorter initial MRI to final reperfusion time, complete reperfusion, and DWI reversal. Results suggest DWI lesions included salvageable tissue. One limitation to this study was retrospective analysis of registry data. There is also potential for overestimation of the proportion of patients with DWI reversible lesions because unstable or expired patients may not have had a follow-up MRI. Another limitation was use of follow-up DWI volumes instead of fluid-attenuated inversion recovery imaging volumes.