Abstract TMP19: MRI Characteristics and Predictors of Diffusion Weighted Hyperintense Lesions After Spontaneous Intracerebral Hemorrhage: A Secondary Analysis of MISTIE-III

Abstract

Introduction: Mechanisms of diffusion weighted hyperintense lesions (DWIHL) after spontaneous intracerebral hemorrhage (ICH) are controversial. We evaluated mechanism and outcome of DWIHL. Methods: Protocolized MRI scans within 7 days from ICH were reviewed from MISTIE-III trial. Imaging analysis included DWIHL, leukoariosis (Fazekas score), enlarged perivascular space (EPVS), and cerebral microbleeds. Multivariable logistic regression analysis was performed to assess predictors and outcomes of having DWIHLs. Favorable outcome was defined as modified Rankin Score 0-3 at 12 months. Results: Of 499 patients, 300 underwent DWI studies (62% lobar ICH; 38% deep ICH) and 178 (59%) had acute DWIHLs (66% lobar; 34% deep). DWIHL locations were perihematomal in 140 (79%); and remote in 96 (54%). In multivariable regression analysis, DWIHLs were associated with initial mean arterial pressure [MAP] (odds ratio [OR]: 1.004; 95% confidence interval [CI]: 1.002-1.01), initial ICH volume (OR: 1.004; 95%CI: 1.001-1.01), NIHSS at randomization (OR: 1.01; 95%CI: 1.01-1.02), hypertension history (OR: 1.41; 95%CI: 1.04-1.93), and Fazekas score (OR: 1.04; 95%CI: 1.01-1.08). Patients with DWIHLs were less likely to have favorable outcome (66% vs. 50%; OR: 0.89; 95%CI: 0.81-0.99) after adjusting for ICH severity; however, the presence of DWIHLs did not confer an independent mortality risk at 12 months. In addition, perihematomal DWIHLs were associated with ICH volume (OR: 1.003; 95%CI: 1.00-1.01), NIHSS (OR: 1.01; 95%CI: 1.00-1.02), deep location (OR: 1.25; 95%CI: 1.10-1.42), and centrum semiovale EPVS score (OR: 0.99; 95% CI: 0.99-1.00). Remote DWIHLs were associated with Fazekas score (OR: 1.17; 95%CI: 1.06-1.29), centrum semiovale EPVS score (OR: 1.01; 95%CI: 1.00-1.01), atrial fibrillation (OR: 1.40; 95%CI: 1.04-1.90), and maximal ΔMAP on first 24 hours (OR: 1.004; 95%CI: 1.001-1.006). Conclusions: DWIHLs were common (59%) in patients after spontaneous ICH, predominantly in lobar locations and were associated with unfavorable neurologic outcome. While perihematomal DWIHLs were associated with ICH severity, remote DWIHLs suggested different mechanisms including acute blood pressure reduction, cardiac emboli, and white matter disease severity.