Exploring the Variations in Angles Around Basilar Bifurcation Categorized by Aneurysm Locations

Vascular bifurcation sites have been identified as preferential locations for intracranial aneurysm presence. The distal bifurcation of the basilar artery (BA) is known for its intricate geometry and frequent association with basilar aneurysms. Previous research on BA apex angles and BA aneurysms predominantly focused on tip aneurysms of the BA. Meanwhile, BA trunk aneurysms have not received much attention. Furthermore, limited attention has been given to the angles between the posterior cerebral artery (PCA) and the superior cerebellar artery (SCA). Our study aimed to address this lack of information and explored potential variations in BA angles across different types of BA aneurysms (basilar tip and trunk aneurysms). The study group comprised a cohort of thirty-three patients selected through a retrospective analysis of patient data from the AneuX project, a multicenter database on intracranial aneurysms. These patients were categorized into basilar trunk, basilar tip aneurysm, and non-BA aneurysm subgroups, each consisting of eleven patients. We investigated the angles among PCA, PCA-SCA, and SCA-BA in all patients. Significant differences were observed between the basilar trunk and tip aneurysm groups in the PCA and PCA-SCA angles. Notably, the angles within the non-BA group were found to fall within the range between the basilar tip and trunk groups. In conclusion, we propose a classification scheme for BA aneurysms and suggest considering PCA-SCA angles in exploring the correlation between BA angles and the presence of aneurysms.