Basilar Artery Plaque Distribution, Pontine Infarction and Vertebrobasilar Artery Geometry: A Magnetic Resonance Imaging Study

Background: Basilar artery (BA) atherosclerosis is a common cause of posterior-circulation ischemic stroke. In this study, we investigate the relationship between BA plaque distribution, pontine infarction (PI) and vertebrobasilar artery (VBA) geometries. Methods: 86 patients with BA plaque were enrolled in this study, the VBA geometry was classified into four configurations: walking, tuning fork, lambda, and no confluence. The AP-Mid-BA, Lateral-Mid-BA, and VA-BA angles were measured on three-dimensional time-of-flight magnetic resonance angiography. Patients underwent high-resolution magnetic resonance imaging to evaluate the BA plaque distribution (either anterior, posterior, or lateral wall). Acute and subacute PIs were identified by T2 weighted imaging-fluid-attenuated inversion recovery and diffusion-weighted imaging.Results: BA plaques in patients with PI were more frequently located at the posterior wall (50.00%) than at the anterior (10.00%) and lateral (37.50%) walls (P =0.028).Compared with patients without pontine infarction, patients with pontine infarction were more likely to have plaque distributed at the posterior wall (P = 0.009). In the tuning fork group, BA plaques were evenly distributed. BA plaques were more frequently located at the lateral wall than at the anterior and posterior walls in patients with walking, lambda, and no confluence geometry (all P ≤ 0.05). The AP-Mid-BA angle in patients with a tuning fork configuration (14.950±11.660) was lower than that in patients with other vascular geometries (P=0.001); there was no significant difference in the VA-BA angle and lateral-mid-BA angle among the four VBA geometries (P >0.05).Conclusion: VBA configuration strongly influences BA plaque distribution and BA plaque distribution was associated with PI.