[Cerebral ischemia and hemorrhage; computed tomography and angiography]

Neuroradiological characteristics of cerebral embolism and hemorrhage were discussed on computed tomography (CT) and angiography. Clinically, cardiogenic embolism was one of major problems in cerebral embolism. On CT, size of the ischemic region, mass effect and frequency of hemorrhagic infarct were most prominent in cerebral embolism. It is difficult to diagnose cerebral infarction within 6 hours of their onset on CT findings. The following signs by Tomura would be important criteria for identifying embolic infarction in the middle cerebral and internal carotid arteries: (a) obscured outline or partial disappearance of the lentiform nucleus, (b) slight decrease in tissue density, (c) effacement of the cortical sulci. Angiographic characteristics of embolism and thrombosis were discussed in terms of shape and configuration at the stump of the occluded arteries, formation of collateral pathway and recanalization. Cerebral hemorrhage were also compared between pathological and CT findings. Indication of cerebral angiography to patients of cerebrovascular disease was also discussed.