Vertebral Artery Asymmetry: Frequency, Degree, and Clinical Significance
DOI:
https://doi.org/10.47363/JIMRR/2026(5)154Keywords:
Vertebral Artery, Asymmetry, Hypoplasia, MRI, Posterior Circulation, Vertebrobasilar InsufficiencyAbstract
Background: Vertebral Artery (VA) asymmetry is a common anatomical variant associated with altered hemodynamics and increased risk of posterior circulation ischemia. Despite its clinical relevance, population-specific data on VA asymmetry remain limited, particularly in Eastern European cohorts.
Objective: To assess the frequency and degree of VA asymmetry using Magnetic Resonance Imaging (MRI) and to evaluate its potential clinical significance in a hospital-based patient population.
Materials and Methods: Fifty patients (22 men, 28 women; mean age 52.3±14.1 years) who underwent cranial and cervical MRI at the Grodno Regional Emergency Hospital were retrospectively enrolled. VA diameters were measured bilaterally at the C5-C6 level. Asymmetry was defined as an Asymmetry Index (AI) exceeding 25%. Hypoplasia was defined as a diameter below 2.0 mm. Statistical analysis was performed using the Mann-Whitney U test and chi-square test.
Results: The mean right VA diameter was 3.42±0.61 mm and the mean left VA diameter was 3.18±0.58 mm (p=0.043). Significant asymmetry (AI>25%) was detected in 14 patients (28.0%). Right-sided dominance was observed in 31 patients (62.0%), left-sided dominance in 12 (24.0%), and codominance in 7 (14.0%). VA hypoplasia was identified in 10 patients (20.0%). Patients with VA hypoplasia reported a significantly higher prevalence of vestibular symptoms and headache (p<0.05).
Conclusion: VA asymmetry and hypoplasia are common findings on routine MRI. These variants should be considered in clinical practice when evaluating patients with posterior circulation symptoms. Population-based morphometric data can contribute to improved radiological interpretation and neurosurgical planning.
