In vivo differentiation of edematous changes after stroke in spontaneously hypertensive rats using diffusion weighted MRI.

Apparent diffusion coefficients (ADCs) of tissue water were determined in chronic brain lesions of a rat stroke model, the stroke-prone spontaneously hypertensive rat, and compared with histology. ADCs increased in the order normal < edema < gliosis < cyst. The differences between individual groups were statistically significant. The increase in ADC is thought to mainly reflect a relative increase in the extracellular space in brain tissue. ADC may be a new parameter for tissue characterization.