A Model to Predict the Histopathology of Human Stroke Using Diffusion and T2-Weighted Magnetic Resonance Imaging

Abstract

Background and Purpose We sought to identify MRI measures that have high probability in a short acquisition time to predict, at early time 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 T ₂ to ischemic brain tissue histopathology. In eight stroke patients we measured ADC _w and T ₂ 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 T ₂ can now be tested for its potential to predict reversible and identify irreversible cellular damage in human ischemic brain regions.