Radiological observations of the branches of circle of willis for surgical perception

Introduction and Aim: The Circle of Willis (CoW) is an arterial hexagon in the interpeduncular fossa formed by the basilar and internal carotid arteries. It permits anastomotic circulation between that two-arterial system. Variations in the pattern and the calibre of the arteries that make up the CoW were common. Few noted variations include hypoplasia or aplasia of either one or both posterior or anterior communicating arteries, aplasia, or fenestrations of the anterior communicating artery. Considering the surgical importance of this arterial circle, as it allows equalization of blood flow between the two sides of the brain, this observational study was done to identify the variations in the formation pattern and the gross morphometry of CoW. Materials and Methods: Thirty radiological images of patients undergoing neurovascular imaging for various reasons in the Department of Radiology and patients were obtained for the study. Results: Among the 30 studied CT and MR angiographic images, 21 (73.3%) of the circles exhibit the usual pattern of CoW formation, and the remaining 9 (27.7%) showed variations. Among the 30 radiological images, 25 (83.33%) were complete circles, 4 (13.33%) were incomplete in the posterior part and 1 (3.33%) was incomplete in the anterior part of the CoW. Conclusion: Understanding the typical formation of CoW and its variations is essential in the surgical correction of a few intracranial emergencies like hemorrhage, infarction, aneurysms, and other neurovascular surgeries of the brain.