Natural History of Stroke: Cause and Development

Study Description: This is a natural history/disease pathogenesis protocol for evaluation of patients with or at risk of acute stroke, transient ischemic attack (TIA), or other disturbances of cerebrovascular circulation. The purpose of this protocol is to generate natural history data to serve as the basis for future hypothesis-driven protocols as well as to contribute to the clinical and physiological understanding of cerebrovascular disease through the description of disease manifestation and the relationship among clinical, hematologic, and radiologic variables, as well as identifying potential subjects for future studies on stroke and other cerebrovascular diseases. Objectives: * To establish a registry of subjects with cerebrovascular disease including clinical, laboratory, and radiological variables associated with hemorrhagic and ischemic stroke, TIA, and other disturbances of cerebrovascular circulation. * To characterize the natural history of acute stroke, TIA, and other disturbances of cerebrovascular circulation on these variables. * To evaluate the relationship among these variables by exploratory analyses and to generate hypotheses for future testing. * To identify potential subjects for research studies on stroke and other cerebrovascular diseases. Endpoints: A primary purpose of this observational protocol is to discover and study new imaging biomarkers that are i) relevant to the acute presentation and severity, ii) predictive of clinical outcome, and iii) are useful for stratifying the biological response as reflected in blood-biomarker and gene expression studies. As such, the primary outcome is the results from the imaging studies. Primary Outcome Measures Prevalence and type of abnormalities seen on neuroimaging as a function of time from acute insult such as: * Imaging positive for acute ischemic cerebral vascular syndrome ( AICS positive )\[1\] * Presence of a lesion on diffusion, perfusion, and mismatch between the two * Evidence of a vascular occlusion on MR angiography * Evidence of a thrombus or hemorrhage on T2\* GRE imaging * Blood-brain barrier disruption as evidence by HARM \[2\] * The evolution of these markers with time and treatment Secondary Outcome Measures * Stroke severity as measured by NIHSS as a function of time since index event. * Clinical outcome measured using modified Rankin Scale and Barthel Index * Gene expression profiles and biomarker levels obtained from blood samples.