Tissue-specific analysis of perfusion- and diffusion-weighted MR imaging of acute ischemic stroke

Magnetic resonance perfusion- and diffusion-weighted imaging can help identify tissue at risk of infarction in acute ischemic stroke. Parameters derived from these imaging methods have been shown to be moderately useful in predicting tissue outcome. Further refinement of these prediction methods is necessary to have a clinical impact in selecting patients for thrombolysis. One such refinement may include accounting for tissue-specific perfusion and diffusion characteristics of gray and white matter. This thesis proposes a novel technique for performing such a tissue-specific analysis and confirms different cerebral blood flow characteristics between these tissue types in ischemic compartments of acute ischemic stroke patients. It also describes a method for determining tissue-specific perfusion and diffusion thresholds that distinguish infarct from benignly oligemic tissue. This thesis confirms that gray and white matter have different perfusion and diffusion thresholds for infarction and that tissue-specific analysis is necessary to optimally identify tissue at risk.