Early Diffusion-Weighted Imaging and Perfusion-Weighted Imaging Lesion Volumes Forecast Final Infarct Size in DEFUSE 2

Abstract

Background and Purpose—: It is hypothesized that early diffusion-weighted imaging (DWI) lesions accurately estimate the size of the irreversibly injured core and thresholded perfusion-weighted imaging (PWI) lesions (time to maximum of tissue residue function [Tmax] >6 seconds) approximate the volume of critically hypoperfused tissue. With incomplete reperfusion, the union of baseline DWI and posttreatment PWI is hypothesized to predict infarct volume.Methods—: This is a substudy of Diffusion and Perfusion Imaging Evaluation for Understanding Stroke Evolution Study 2 (DEFUSE 2); all patients with technically adequate MRI scans at 3 time points were included. Baseline DWI and early follow-up PWI lesion volumes were determined by the RAPID software program. Final infarct volumes were assessed with 5-day fluid-attenuated inversion recovery and were corrected for edema. Reperfusion was defined on the basis of the reduction in PWI lesion volume between baseline and early follow-up MRI. DWI and PWI volumes were correlated with final infarct volumes.Results—: Seventy-three patients were eligible. Twenty-six patients with >90% reperfusion show a high correlation between early DWI volume and final infarct volume (r=0.95;Pr=0.86;P=0.002). Using all 73 patients, the union of baseline DWI and early follow-up PWI is highly correlated with final infarct volume (r=0.94;P6 seconds) volumes provide a reasonable approximation of final infarct volume after endovascular therapy.