Infundibular widening mimicking anterior communicating artery aneurysm: report of 2 cases.

Because infundibular widening most commonly appears at the origins of the posterior communicating artery and anterior choroidal artery from the internal carotid artery, its occurrence in association with the anterior communicating artery (ACoA) or the A1-A2 junction can be misinterpreted as an ACoA aneurysm on angiograms. The authors report on 2 such cases; one in a 73-year-old woman with infundibular widening of the recurrent artery of Heubner, and the other in a 44-year-old woman with infundibular widening of a perforating vessel from the ACoA. The correct diagnosis was established based on surgical exploration. In addition, grayscale modification of 3D reconstruction images of preoperative digital subtraction angiography revealed the cases of the recurrent artery of Heubner and perforating artery of the ACoA arising from the apex of the infundibular widening.