Objectives: The diameters of the vertebral arteries (VAs) are very often unequal. Therefore, we investigated if unequal VA flow contributes to the development of basilar artery (BA) curvature and if it is a link to the laterality of pontine or cerebellar infarcts occurring around the vertebrobasilar junction.
Methods: We analyzed radiological factors (infarct laterality, VA dominance, BA curvature, and their directional relationships) of 91 patients with acute unilateral pontine or posterior inferior cerebellar artery (PICA) territory infarcts. The 'dominant' VA side was defined as either that the VA was larger in diameter or the VA was more straightly connected with the BA, if both VAs looked similar in diameter on CT angiography. Multiple regression analysis was performed to predict moderate-to-severe BA curvature.
Results: The dominant VA was more frequent on the left side (p<0.01). Most patients had an opposite directional relationship between the dominant VA and BA curvature (p<0.01). Pontine infarcts were opposite to the side of BA curvature (p<0.01) and PICA infarcts were on the same side as the non-dominant VA side (p<0.01). The difference in the VA diameters was the single independent predictor for moderate-to-severe BA curvature (OR per 1-mm, 2.70; 95% CI, 1.22-5.98).
Conclusions: Unequal VA flow is an important hemodynamic contributor of t BA curvature and development of peri-vertebrobasilar junctional infarcts.