Background: The pathogenesis of intracranial aneurysms (IAs) is multifactorial and includes genetic, environmental, and anatomical influences. Hemodynamic stress plays a particular role in the formation of IAs, which is conditioned by the geometry and morphology of the vessel trees.
Objective: To identify image-based morphological parameters that correlated with the formation of basilar artery tip aneurysms (BTA) in a location-specific manner.
Methods: Morphological parameters obtained from CTAs of 33 patients with BTA and 33 patients with aneurysms at other locations were evaluated with Slicer, an open source image analysis software, to generate 3-D models of the aneurysms and surrounding vascular architecture. We examined the diameters and vessel-to-vessel angles of the main vessels at the basilar bifurcation in patients with and without BTAs. In order to control for genetic and other risk factors, only patients with at least one aneurysm were included. Univariate and multivariate analyses were performed to determine statistical significance.
Results: Sixty-six patients (33 BTA, 33 other) were analyzed who were evaluated from 2008-2013. Multivariate logistic regression revealed that a larger angle between the posterior cerebral arteries (OR 1.04, p=1.42×10-3) and a smaller basilar artery diameter (OR 0.23, p=0.02) were most strongly associated with BTA formation after adjusting for other morphological and clinical variables.
Conclusion: Larger posterior cerebral artery angles and smaller basilar artery diameters are associated with the formation of basilar tip aneurysms. These parameters are easily measurable by the clinician and will aid in screening strategies in high-risk patients.
From: Effect of vascular anatomy on the formation of basilar tip aneurysms by Can et al.