A Study of Intravenous Thrombolysis With Alteplase in MRI-Selected Patients

This study was jointly developed and is jointly led by investigators at Massachusetts General Hospital and the intramural division of NINDS. We are doing this research study to find out if Activase ® (also called alteplase or rt-PA) can safely be given to people with an acute ischemic stroke when their stroke onset was not witnessed making them ineligible for standard thrombolytic (clot busting) therapy. We also want to find out if rt-PA can help people recover better from their stroke. The purpose of this study is to: 1) see if it is safe to give intravenous (IV) rt-PA to people with unwitnessed stroke but with MRI evidence of early ischemic stroke, 2) see if rt-PA is effective if given to people who are selected for treatment based on MRI evidence of an early stroke, and 3) get information about this new MRI diagnostic methods for guiding stroke treatment.