بررسی واریاسیونهای آناتومیک حلقه عروقی مغز(حلقه ویلیس) از طریق آنژیوگرافی مغزی

ABSTRACT Anatomical variations have great importance among various medical disciplins. The significance of these variations differ from some points of view including system, site and degree of variation. Vascular system is a common site of variations. The importance of this system in supplying the organs, specially the brain has made it to be in focus for its variations. The main source of the brain blood supplying is the circle of willis. Many anatomical variations of the adult arterial circle have been described. To our knowledge, despite of many documents of anatomical variations of willis circle in other population, no documents have been reported regarding to Iranian population. Thus, in order to determine the kind and the incidence of the variants of willis circle, by using cerebral angiography we studied the willis circle in Iranian race patients referred to department of radiology. Variants for the main branches of willis, including abnormal site of ramification, number of branching, agenesy and external diameter were noticed. In addition, other ones like internal & external carotid, basilar artery and middle cerebral artery were noticed too. Results of this study showed some variations in anterior and posterior communicating artery, middle cerebral artery and basilar artery. The recognition of anatomical variations of the circle of willis is important in diagnostic procedures, prognosis of the patients with cerebrovascular disorders and also allows the neurosurgeons to construct better and safer microdissection plan to save time on the one hand and to prevent postoperative neurological deficits on the other hand.