A model to predict the histopathology of human stroke using diffusion and T₂-weighted magnetic resonance imaging

Background and Purpose: We sought to identify MRI measures that have high probability in a short acquisition time to predict, at early points after onset of ischemia, the eventual development of cerebral infarction in clinical patients who suffer occlusion of a cerebral artery. Methods: We developed an MR tissue signature model based on experimentally derived relationships of the apparent diffusion coefficient of water (ADC(w)) and T₂ to ischemic brain tissue histopathology. In eight stroke patients we measured ADC(w) and T₂ intensity using diffusion-weighted echo-planar imaging (DW- EPI). Tissue signature regions were defined, and theme maps of the ischemic focus at subacute time points after stroke onset were generated. Results: Five MR signatures were identified in human stroke foci: two that may predict either cell recovery or progression to necrosis, one that may mark the transition to cell necrosis, and two that may be markers of established cell necrosis. Conclusions: An MR tissue signature model of ischemic histopathology using ADC(w) and T₂ can now be tested for its potential predict reversible and identify irreversible cellular damage in human ischemic brain regions.