Aneurysms of the anterior communicating artery and gross anomalies of the circle of Willis.
D002339:Carotid Arteries / Q000002:abnormalities*; D002533:Cerebral Angiography; D002536:Cerebral Arteries / Q000002:abnormalities*; D002941:Circle of Willis / Q000002:abnormalities*; D003097:Collateral Circulation; D006801:Humans; D002532:Intracranial Aneurysm / Q000209:etiology*; D008297:Male; D008875:Middle Aged