Aberrant Origin of Left Vertebral Artery – Multidetector Computed Tomography Study

Abstract

Background: The vertebral arteries originating from respective subclavian arteries are the major source of oxygenated blood to posterior cerebral circulation and supply the upper spinal cord, brain stem, cerebellum, and occipital lobes of the cerebrum. Paucity of radiological studies prompted us to undertake this study which aims to analyze the variations in origin of left vertebral artery (LVA). Materials and Methods: This is a retrospective cross-sectional study of contrast-enhanced computed tomography chest scans of 710 subjects retrieved from the archives of a single imaging center. Observations and Discussion: Normal origin of LVA from the left subclavian artery (LSA) in the root of the neck was noted in 90.56% and variant origin in 9.44% of cases. Four-branched aortic arch (AA) with direct AA origin of LVA was observed in 6.76% of cases. An atypical three-branched pattern with LVA origin between the bovine trunk (common trunk of brachiocephalic trunk [BCT] and left common carotid artery [LCCA]) and LSA was seen in 0.84% of cases. Common origin of both LVA and LSA from a vertebro-subclavian trunk (VST) is found in 0.98% of cases. LVA as the last branch of arch distal to LSA and LVA of arch origin associated with aberrant right subclavian artery were noted in 0.14% of cases each. A rare but important observation is the presence of two common trunks (bovine trunk (BCT + LCCA) and VST (LVA + LSA) in an atypical two-branched fashion found in 0.56%. Conclusion: Critical knowledge of variations of the origin of LVA is clinically relevant as such variations are more prone to vascular pathologies. Variations of the LVA are thought to alter cerebral hemodynamics and can produce cerebral dysfunction. Preprocedural knowledge of such variations aids in the successful accomplishment of catheterization of LVA and avoids complications during neuroradiological interventions and surgical procedures.