The diagnosis of cerebral infarction by angiography is based on a variety of findings, involving both anatomical and pathophysiological considerations. These findings at the time of angiography are dependent upon the type of infarction that we are dealing with (hemorrhagic versus nonhemorrhagic), its location, and the time interval between the onset of symptoms and the performance of the angiographic procedure. Rapid serial angiography is indispensable in the study of cerebral infarction. Most patients are never referred to the Department of Radiology for cerebral angiography, but the number seen has increased of late because of the importance given to possible correctible lesions in the extracranial vessels. Other cases are referred because a hemorrhagic infarction requiring surgical intervention is suspected or because the diagnosis of cerebral infarction cannot be made with certainty on clinical grounds. Because of our desire to arrive at an accurate diagnosis and because the morbidity of the procedure...