VARIATIONS OF CIRCLE OF WILLIS - DIGITAL SUBTRACTION ANGIOGRAPHIC STUDY IN A SOUTH INDIAN POPULATION

Background: The Circle of Willis is an arterial polygon at the base of the brain, forming a vital collateral network for adequate cerebral perfusion. The pattern and caliber of vessels that comprise the circle show considerable individual variation. Some of these changes may increase the risk of formation of aneurysm and alter the severity of symptoms of cerebrovascular diseases, like stroke and infarcts. Objectives: The aim of this study is to analyse the variations of the circle of Willis with the help of digital subtraction angiography Methodology: This cross-sectional study was conducted in the department of Neurosurgery, Coimbatore Medical College Hospital, for a period ranging from January 2021 to March 2023. Patients admitted to undergo digital subtraction angiography (DSA) for various indications were included in this study. Circle of Willis was analyzed with reference to complete or incomplete circle, asymmetry in configuration, variations in size, presence of multiple anomalies and type of anomaly. Results: Morphology of the Circle of Willis and its variations were studied in digital subtraction angiography (DSA) of 188 patients. Normal pattern was noted in 118(62.76%) and the remaining 70(37.24%) had one or more variations 56(80%) had variations in anterior circulation and 14(20%) had variations in posterior circulation. Variations on the right were 28(40%) while 40(57.14%) were on the left. Incomplete circle was found in 22(31.42%). In 124 cases aneurysms were observed. Conclusion: Variation in the morphology of circle of Willis is common, with the most common being variation in the PCom in this study.