Acute Stroke Studies

Stroke is the third leading cause of death and the leading cause of adult morbidity in the United States. Recent thrombolytic trials using tissue-plasminogen activator (t-PA) have established new treatment options for acute stroke patients, however, a benefit has only been shown if t-PA can be given within three hours after the onset of a new ischemic stroke. No overall benefit for the study groups has been shown beyond the three-hour time window. However, there was evidence in recent studies that t-PA might helpful even beyond the three hour time window if appropriate selection criteria could be established to determine which patients would have the greatest benefit and which patients might be at risk for harmful side effects from thrombolytic therapy. Those selection criteria have to incorporate information on tissue pathophysiology and not solely on a ticking clock. Multimodality magnetic resonance imaging is able to provide the pathophysiological basis for selecting patients presumed to have the highest benefit from thrombolytic therapy and for identifying those patients at greatest risk for adverse side effects. We will evaluate MR imaging based treatment rules to predict patients most likely to benefit from t-PA beyond the three-hour time window. Furthermore, we will assess the safety and tissue efficacy of intravenous and intraarterial t-PA in patients with certain MR imaging patterns. This will help us to tailor appropriate therapeutic interventions such as giving potentially harmful thrombolytic medications to only those patients that may have the greatest benefit from it based on data determined in this study. Cerebrovascular disease is the third leading cause of death in the United States and a major cause of adult disability. Most patients that survive an ischemic or hemorrhagic stroke have persistent and disabling deficits. The mechanisms of recovery following stroke are poorly understood and therefore poorly manipulated by therapeutic interventions. Good functional outcome has been associated with smaller size and specific location of the stroke, particularly important is the integrity of the pyramidal system. However, the precise brain areas and physiological processes that are important to enable recovery have not been determined.

We are currently involved in several experimental treatment trials assessing the use of innovative neuroimaging techniques in making treatment decisions.