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

This study was jointly developed and is jointly led by Massachusetts General Hospital and the NINDS. This is a multi-center, open-label, Phase IIa safety study in adult acute ischemic stroke patients to determine if it is safe to extend intravenous thrombolytic treatment to subjects who are evaluated within 24 hours from last known well ("stroke onset") and eligible to receive thrombolytic treatment within 4.5 hours from symptom discovery with the assistance of an MRI-based "witness" when no human witness of stroke onset is available. The study is designed to investigate the safety in using standard diagnostic MRI in selecting patients for thrombolytic therapy when the last known well time places the patient beyond the current IV thrombolytic time-window.