Anatomical Variations in the Circulus Arteriosus Cerebri with Clinical Importance – Results of an Magnetic Resonance Angiography Study and Review of Literature

OBJECTIVES: Anatomy of circulus arteriosus cerebri (CAC) shows wide variation in different individuals, and population groups and has vital clinical significance in causation and presentation of clinical disease. The literature revealed a connection between the variations of CAC and cerebrovascular disease, ischemia, stroke, aneurysms, and atherosclerosis. MATERIAL AND METHODS: In this study, 513 patients without clinical manifestation in regard to cerebrovascular diseases, who are considered healthy on CAC anatomy, are included. Patients were instructed by clinicians for head imagery with magnetic resonance angiography examination during 2016–2017 periods. RESULTS: After statistical analysis, 43.27% were male while 56.72% female, 39% were younger than 40 years old. Age interval lies from 11 to 84 years old, mean age 46. The most common variations or 9.74% is when communicant anterior artery absence and absence of both posterior communicant arteries (Type G*/E) more rarely is H*/G (0.2%), G*/D (1.75%), G*/G (0.6%), H*/D (0.4%), H*/E (3.39%), H*/H (0.4%), J*/E (0.6%), while combination J*/D, J*/G, J*/H, G*/H not found. The most often combination is absence of anterior communicant artery and absence of both posterior communicant artery (Type G*/E), more in male 10.36% than female 9.6%. CONCLUSION: The CAC is considered to play a critical role in preventing future stroke events in patients with absent of any of the arteries. Knowledge on variations in arteries forming the CAC is with clinical significance, as it is one of the components of CAC which stabilizes cerebral blood flow when principle conduits fail. Knowing the structure of arteries provide clinical knowledge to the surgeons before planning neurovascular surgeries.