Significance of Subtle Diffusion Weighted Imaging Lesion Dynamics: A Comparative Analysis of Methods for Detecting...

Restrictive diffusion on magnetic resonance imaging is recognized as an early marker of ischemic brain damage, even though diffusion-weighted imaging lesion reversal (DWI-R) is well known. This study aimed to compare methodologies for detecting DWI-R, including voxel-based analysis, which captures subtle lesion dynamics, and to test their correlation with clinical outcomes.

We retrospectively analyzed magnetic resonance imaging data from 216 consecutive patients with acute ischemic stroke obtained before and after endovascular therapy. DWI-R was defined either as an increase in DWI-Alberta Stroke Program Early Computed Tomography Score, a decrease of total DWI signal volume or as partial reversal of the initial DWI lesion, irrespective of the final DWI load. Associations between 3-month poststroke modified Rankin scale score and DWI-R was assessed according to the different definitions of DWI-R using logistic binary regression.

In patients undergoing endovascular therapy, 25% had increased DWI-Alberta Stroke Program Early Computed Tomography Score and 32% showed reduced DWI volume. Both measures were strongly associated with favorable outcomes (modified Rankin Scale score ≤2) with odds ratios of 4.90 and 5.60, respectively (95% CIs: 1.66-14.46 and 2.09-14.98). Voxel-based analysis revealed DWI-R of ≥20% of the initial lesion in 64.5% of cases. Even with an overall increase of lesion volume due to progression elsewhere, ≥20% reversal of initial lesion was associated with a significantly improved outcome compared with <20% reversal, odds ratio 2.22 (95% CIs: 1.05-4.70).

DWI-R was common in patients treated with endovascular therapy and linked to favorable outcomes. Subtle lesion dynamics detected only by the voxel-based analysis also conferred significant clinical benefits, supporting DWI-R as a continuum rather than a binary measure as "present" or "absent."