Morphology and morphometry of the vertebrobasilar system intracranial segment: a computed tomography angiography...

The current computed tomography angiography (CTA) study aimed to investigate the vertebrobasilar system (VBS) intracranial segment variant morphological anatomy and morphometry. Two hundred CTAs of 142 male and 58 female patients (with a mean age of 62.85±14.08) were retrospectively evaluated. Four hundred vertebral arteries (VAs) and 200 basilar arteries (BAs) were studied. In the V3 segment, the vessel's high riding course was identified in 10.8%. An arcuate foramen (AF) was identified surrounding the V3 segment in 12.0%. When AF was present, the V3 diameter was statistically significantly narrower (P<0.001). The V4 segment was hypoplastic in 11.0% and fenestrated in one case (0.3%). The posterior inferior cerebellar artery typically originated from the V4 segment in 76.5%. On the BA morphology, we classified the vessel according to its inclination. The most common type was the J-shaped (55.5% of cases). The BA inclination was positively correlated with the vessel's length (P=0.002). The VBS intracranial segment was systematically investigated. Knowledge of the VBS typical and variant anatomy is essential for anatomists, radiologists, and clinicians. The most important findings was the following: (1) the AF presence significantly narrowed the VA diameter, which could lead to the vessel's compression, (2) the BA linear length (bending or inclination) positively correlated with the BA length, and (3) the V4 length was positively correlated with its diameter.