Retrospective Study of Normal Variations in Vertebral Artery on CT angiography with special emphasis on relevant embryology

Abstract

Purpose:The Vertebral arteries (VA) nourishes the posterior circulation supplying the brain. These variant patterns can be correlated to their development and such embryological variants should be well known before diagnosing or planning interventions in the head and neck regions. Methods: After due ethical clearence, CT angiography of 70 subjects were studied for variations of VA under, V1 – From origin to entrance into the FT (foramen transversarium), V2- Part inside FT, V3- from its exit from FT till it pierces the cranial Dura mater, V4- Intracranial part. Further, VA was observed for its origin, dominance, level of entry in FT, and any associated anomalies. Results:The VA was found mostly to be codominant. There was an opposite directional relationship between the BA curvature and the dominance of VA. The association of ischemic events with hypoplastic VA was more on the left side (66.67%). Left VA originated from Aorta in 4.3% subjects. 1.4% cases presented with dual origin of VA. The abnormal origin of the LVA from Aorta presented with a higher rate of anomalous entry (C4, C5) into FT (C6) and was found to be statistically significant. Conclusion:Our study attempts to identify and document anatomical variations present in VA in the population of North-East India by CT angiography and to correlate their relevant development which may further help us understand these patterns for better diagnostic and therapeutic outcomes.