Measurement of the length of vertebrobasilar arteries: A three-dimensional approach

Under the assumption that neurovascular compression can be caused by elongation or kinking of the artery, we measured the length of each section of the vertebrobasilar artery, compared the lengths between various age groups, and evaluated the involvement of the arterial sections in brain stem compression in 1000 cases. The lengths of the posterior inferior cerebellar artery (PICA)-union of both vertebral arteries (union), union-anterior inferior cerebellar artery (AICA), AICA-superior cerebellar artery (SCA), and union- superior cerebellar artery were measured using an arterial length measuring tool applied to three-dimensional images. The presence of arterial compression of the brain stem was also evaluated. The mean age of the participants was 66.8 ± 12.9 years, and 44.8% were men. Intraclass correlation coefficients for both inter-rater reliability and intra-rater reliability were high in all sections. The vessel lengths of left AICA-SCA (P < 0.001), left union-SCA (P < 0.0001), left PICA-union (P = 0.03), right AICA-SCA (P = 0.002), right union-SCA (P < 0.0001), and right PICA-union (P = 0.04) increased with age, but each R² was less than 0.05. Brain stem compression by PICA or vertebral artery was identified in 13.8% of cases. The proportion of the presence of brain stem compression was significantly higher in the cases with arterial elongation than in those without (P = 0.01). Vessel length increased with age, but age had a relatively small impact on the elongation of vertebrobasilar arteries. Brain stem compression might be caused by kinking of the artery rather than arterial elongation.