Investigation of the formation and morpometric properties of circulus arteriosus cerebri by radiological methods

Circulus arteriosus cerebri is an important arterial ring that provides adequate cerebral blood flow in case of occlusion/stenosis of the arteria carotis interna. Knowing the structure and variations of the Willis polygon is important for understanding surgical interventions and vascular diseases. Our study was carried out on images created by 3D-TOF-MRA method of a total of 111 patients, 46 men and 65 women, without a pathological history. Variation models were determined by examining Willis polygons. The diameters of the arteries forming the Willis polygon were measured. In addition, the diameter of the arc made by the arteria carotis interna in the canalis caroticus and the diameter of the artery were measured and proportioned. The most common pattern in the anterior part of the Willis polygon was the absence of arteria communicans anterior with a rate of 27%. In the posterior part of the polygon, the most common pattern was the absence of arteria communicans posterior with 65%. The number of patients with a complete Willis polygon was 4. We determined that the variation types detected in our study were not different between female/male genders and right/left sides (p>0.05). We also determined that the diameters of the arteries forming the polygon were not different between female/male genders and right/left sides (p>0.05). We determined that the ratio between arteria carotis interna and the diameter of the artery was not different between genders and sides (p>0.05). We determined that the diameters of the right arteria carotis interna were statistically different between men and women (p<0.05). Also, we determined that there was a statistically significant difference between men and women in terms of left arteria communicans posterior diameters (p<0.05). This shows that there is an asymmetry in the blood circulation of the cerebral hemispheres. We think that, different studies should be conducted to determine whether this also indicates lateralization. In addition, we think that the variation types and frequency we detected, provide useful information for other studies and interventions in this region, and different studies should be conducted to determine the Willis polygon variations comparing with other radiological imaging methods.