Abstract 3130: A 101 cm 3 Diffusion-Weighted Imaging (DWI) Cerebral Infarct Volume is the Maximum Volume Compatible with Good 30- Day Functional Outcome

Abstract

Background: Several predictors of clinical outcome have been identified in acute ischemic stroke patients, including age, National Institutes of Health Stroke Scale scores (NIHSS), and large vessel occlusion. Predicted infarct volumes are thought to generally correlate with clinical outcome, however, to date, mostly small studies have failed to demonstrate a convincing relationship between Diffusion-weighted imaging (DWI) volumes and clinical outcome, and this correlation is controversial. Hypothesis: We hypothesized that final DWI infarction volumes would correlate with 30-day modified Rankin Score (mRS). We also sought to describe the maximum cerebral infarct volume compatible with a favorable 30 day (mRS of 0-2) outcome. Methods: We retrospectively reviewed a prospectively collected database of acute stroke patients with large vessel occlusion who were potential intra-arterial therapy candidate, which recently incorporated systematically collected imaging data at our large academic medical center. Additional inclusion criteria were MRI on admission as per our hyperacute stroke treatment protocol, and available 30-day mRS (n=91). Final DWI volume was obtained from the last MRI the patient had during their stroke treatment admission. Differences between final DWI volume and 30-day mRS were analyzed using the Kruskal-Wallis test. Results: See Table 1 for DWI volumes by individual mRS. There was a strong overall positive relationship between final DWI volume and 30-day mRS [Kruskall Wallis p= .0047]. No patient with an mRS of 0 had a DWI volume >12.1 cm 3 . No patients with an mRS of ≤1 had an DWI volume over 85 cm 3 , and no patient with a mRS of ≤2 had a DWI volume over 101 cm 3 . Conclusions: Cerebral infarct volumes strongly correlate with 30-day functional outcome, but there is great individual variability. The maximum infarct volume compatible with survival and mild or less disability at 30 days was 101 cm 3 . In this study, the maximum cerebral infarct volume compatible with zero clinical symptoms or disability at 30 days was 12.1 cm 3 .