Magnetic Resonance Imaging Markers of Brain Health Improve Assessment of Functional Outcome After Acute Ischemic Stroke: A Quantitative Comparison Study.

OBJECTIVES

To compare quantitative MRI markers of brain health in their ability to predict functional outcome after acute ischemic stroke (AIS).

METHODS

We included AIS survivors from the international MRI-GENIE study (multicenter; 2003-2011) with acute T2-FLAIR imaging. Automated pipelines estimated white matter hyperintensity volume (WMHv), brain volume, and intracranial volume (ICV). Assessed brain health markers included: brain parenchymal fraction (brain volume relative to ICV); radiomics derived brain age; brain reserve (normal appearing brain volume relative to ICV), and effective Reserve (eR, latent variable based on age, WMH load and brain volume). We added the markers to a clinical reference model, comparing model performances between separate multivariable regression models in their prediction of unfavorable outcome (90-day modified Rankin Scale score 3-5), using Bayesian Information Criterion (BIC).

RESULTS

We analyzed 2,223 patients (median age 67 years, 45% female, 24% unfavorable outcome). All models using brain health markers outperformed the clinical reference model (ΔBIC > 10). The eR model showed the lowest BIC value (BIC=2171.8), providing strong statistical evidence to outperform the brain age model (BIC=2179.5, ΔBIC > 6), and very strong (ΔBIC > 10) statistical evidence to outperform all other models.

DISCUSSION

Quantitative MRI markers of brain health, especially eR, enhance personalized outcome prognostication after AIS.