Sexual Dimorphism of Morphometric Parameters of the Vertebral Artery: A Retrospective CT Angiographic Study

Abstract

Background and Objectives: Despite the well-documented clinical significance of the Vertebral Artery (VA) in posterior cerebral circulation, standardised normative data stratified by biological sex remain scarce. The aim of this study was to compare morphometric parameters of the extracranial VA between males and females using Multidetector Computed Tomography Angiography (MDCTA).

Materials and Methods: A retrospective analysis of 120 consecutive MDCTA examinations performed between January 2025 and March 2026 was conducted. Sixty males and 60 females, aged 25-75 years, were included. VA diameters were measured at three standardised levels: V1 (origin), V2 (C4 vertebra), and V3 (suboccipital segment). Dominance pattern, asymmetry index, and the prevalence of VA hypoplasia (diameter <2.0 mm) were assessed. Statistical comparisons used the independentsamples t-test and chi-square test.

Results: Males consistently exhibited larger VA diameters than females at all measured levels (p<0.001). The mean right V1 diameter was 4.12±0.68 mm in males versus 3.58±0.61 mm in females. Left VA dominance was predominant in both sexes (56.7% overall). VA hypoplasia was identified in 14 subjects (11.7%), with a higher frequency in females (16.7%) than in males (6.7%), although the difference did not reach statistical significance (p=0.087). Right-sided hypoplasia accounted for 71.4% of all cases.

Conclusions: Significant sexual dimorphism exists in VA diameter across all extracranial segments. These findings underscore the necessity of sex-stratified reference values in clinical imaging interpretation and preoperative planning for cervical and posterior cranial interventions.