Accurate prediction of final lesion is critically important for clinical decision making in the management of acute ischemic stroke patients. In addition to the widely utilized perfusion and diffusion parameters, an MR derived cerebral oxygen metabolism index OMI_R2?, may be a potential candidate for infarction prediction. In this study, I evaluated how these MR parameters may delineate infarction in rats with ischemic injury. In addition, there is overwhelming evidence from animal studies showing that cooling may improve outcome after cerebral ischemia. However, how physiology parameters during ischemic injury are modulated by brain temperature is largely unknown. In this book, I designed an MR compatible focal brain temperature manipulation system, which can regulate brain temperature quickly and accurately. The relationship between T1 and temperature in brain tissue was investigated, which can be used to derive the brain temperature under hypothermic conditions. The relationship between CBF and temperature was also studied under ischemic condition.