Role of Magnetic Resonance Angiography in Evaluation of Variants of Posterior Cerebral Circulation

Background: Anomalies of the posterior cerebral circulation comprising vertebrobasilar arterial system are encountered incidentally in magnetic resonance angiography. Aim: To investigate the role of magnetic resonance angiography in identification of vertebrobasilar arterial anomalies. Methods: This is a retrospective observational study. The study enrolled 39 cases (18 males and 21 females) with variations in the vertebrobasilar arteries out of 59 cases that performed brain magnetic resonance angiography. Cerebral magnetic resonance angiography examinations were analysed for frequency and distribution of variants of vertebrobasilar arteries and their branches. Statistics: Independent t-test was used to compare diameters of hypoplastic vertebral arteries to diameters of normal vertebral arteries. Results: The commonest anomaly of the vertebrobasilar arterial circulation was vertebral artery aplasia/hypoplasia (74%) followed by anomalous foetal origin of posterior cerebral artery (15%). Significant reduction in diameters of hypoplastic vertebral arteries compared to normal vertebral arteries (t=6.6, p<0.0001) was noted. Conclusion: magnetic resonance angiography is a reliable rapid imaging method for detection of vertebrobasilar anomalies.