The broad, long term goals of this research is to improve the diagnosis and treatment of ischemic stroke. In this proposed work we will develop new biomedical imaging technologies based on MRI. In light of recent MRI- based imaging trials which successfully use MRI for stroke triage, there is an unmet need to improve acute- phase physiologic and angiographic imaging in stroke. In this proposal we will develop, validate and perform a pilot study of new MRI pulse sequences that are capable, for the first time, the imaging of volumetric changes in cerebral perfusion, pail collateral flow, and tissue oxygenation in under 10 minutes. Our research group brings together two top-tier research institutes to interactively alter and image cerebral physiology using a novel animal model of ischemic stroke. The use of this model will allow direct visualization of the pial collateral flow, local alterationin cerebral physiology and the hypothesized response to flow augmentation therapy.