Wider ICA Bifurcation Angles Precede Aneurysm Formation

Background: Cerebral bifurcation arterial regions are prone to intracranial aneurysm formation due to increased hemodynamic stress. Although internal carotid artery (ICA) bifurcation (ICAB) aneurysms have a low incidence, they incur high rupture rate of approximately 40% to 50% and are associated with higher rate of recurrence (14% to 22%). Objective: To examine ICAB morphology on healthy, aneurysmal, and nonaneurysmal contralateral bifurcations, including analysis of the vascular optimality principle and the effect of A1 dominance. Design: Single-center, retrospective analysis. Methods: Patients with ICAB aneurysms with high-resolution 3D catheter angiographic volumetric data sets were included. 3D rotational angiography was performed on the nonaneurysmal side as well. Angiographic data from patients without cerebral aneurysms who underwent evaluation for unrelated medical conditions were considered if bilateral angiography was of adequate quality. Angiographic filling of the A1 seg more...