Ruptured aneurysms of anterior cerebral or anterior communicating arteries: CT patterns.

We reviewed the CT findings in 40 patients with ruptured aneurysms of the anterior cerebral or anterior communicating arteries. Within 3 days of the ictus, the common patterns included blood in the pericallosal cistern and interhemispheric fissure, blood in the caval-septal region, unilateral or bilateral frontal hematoma, and diffuse symmetric intraventricular and basal cisternal blood. In 6 of 23 patients with postcontrast studies, an abnormal enhancing region delineated the aneurysmal sac.