Numerous meetings have been devoted to cerebral The angiographic study specifies the indications vascular accidents during the last few years. Never of angiography in the study of cerebral ischemia, and theless our experience at La Salpetriere shows that the techniques to be used. It shows the main etiologic cerebral infarcts are not always well explored. Indi aspects. Because of the important place of vascular cations for angiography today, as well as the main surgery today, it seemed necessary to show also the CT aspects during the evolution of ischemia seem main post operative angiographic aspects. not to be always well known by radiologists. We After CT and angiography, some pages are re therefore thought it useful to have a special issue de served to more modem techniques: positron emis voted to cerebral ischemia; this is also the reason sion tomography which will perhaps allow us to bet why this special issue looks more like a thoroughly ter understand the pathophysiological signification worked out study than one exclusively devoted to a of imaging and magnetic resonance imaging, which limited number of scientific papers. will perhaps allow us to detect ischemic edema in the After a brief clinical and pathophysiological ap reversible stage, prior to frank infarction.