THE TEMPORAL EVOLUTION OF MRI TISSUE SIGNATURES AFTER TRANSIENT MIDDLE CEREBRAL-ARTERY OCCLUSION IN RAT

We have developed a multiparameter magnetic resonance imaging (MRI) cl uster analysis model of acute ischemic stroke using T-2 relaxation tim es and the diffusion coefficient of water (ADC(W)). To test the abilit y of this model to predict cerebral infarction, male Wistar rats (n = 7) were subjected to 2 h of transient middle cerebral artery (MCA) occ lusion, and diffusion and T-2 weighted MRI were performed on these rat s before, during and up to 7 days after MCA occlusion, MRI tissue sign atures, specified by values of ADC(W) and T-2 were assigned to tissue histopathology. Significant correlations were obtained between MRI sig natures at different time points and histopathologic measurements of l esion area obtained at 1 week. In addition, we compared the temporal e volution of MRI tissue signatures to a separate population of animals at which histological data were obtained at select times of reperfusio n. A significant shift (p less than or equal to 0.05) within signature s reflecting tissue histopathology was demonstrated as the ischemic le sion evolved over time. Our data suggest, that the MRI signatures are associated with the degree of ischemic cell damage. Thus, the tissue s ignature model may provide a noninvasive means to monitor the evolutio n of ischemic cell damage and to predict final outcome of ischemic cel l damage. (C) 1997 Elsevier Science B.V.