The computerized tomographic appearance of angiographically occult arteriovenous malformations of the brain.

Eight patients with a histologically proven angiographically occult arteriovenous malformation of the brain had plain and infused computed tomographic (CT) examinations. In five cases angiography revealed a hypovascular mass in three cases the angiogram was normal. On CT examination a high density lesion (six cases) and ventricular asymmetry (five cases) were demonstrated. In three patients presenting with intracerebral hemorrhage, the high density appearance and ventricular compression were accounted for by the presence of hematoma. In three of five seizure patients the high density lesion was associated with calcification while ipsilateral (one case) and contralateral (one case) enlargement of the lateral ventricle was seen. In five of the eight cases the vascular nature of the lesion was suggested by vascular enhancement of the infused CT scan. Glioma was a common misdiagnosis.