1. Symptomatic cerebral infarction within 30 days of enrollment attributed to 70-99% stenosis of a major intracranial artery (carotid artery, MCA stem (M1), vertebral artery, or basilar artery) that is documented by any of the following: MRA, CTA, or catheter angiography. Percent stenosis will be measured according to WASID criteria (= 1 - [Ds / Dn]) x 100% with Ds [diameter of stenosis] and Dn [diameter of normal vessel]).19