Correlation between ponticulus of atlas and abnormal morphology of V3 segment of vertebral artery using multi-slice spiral CT angiography

Objective: To explore the correlation between ponticulus of atlas and abnormal morphology of V3 segment of vertebral artery. Methods: All patients included in this study were underwent CTA and 3D reconstruction examination of intracranial ponticulus and cervical in our workstation, as well as the site, shape of petals and its relationship with vertebral artery was observed. The diameter, shape and trail of vertebral V3 segment were measured and analyzed. The results were analyzed by χ² test. Results: A total of 195 sides (157 cases) ponticulus were detected in 613 cases (1226 sides), the abnormal morphology of V3 segment of vertebral artery were 103 sides and combined with ponticulus 69 sides among them, including (according to side): the collectivity was 8.4% (103/1226), combination ponticulus was 35.4% (69/195), uncombination ponticulus was 3.3% (34/1031), and the risk with ponticulus was increased compared with no ponticulus, and showed statistical significance by Chi-square test (χ² = 215.679, P = 0.001). The difference of abnormality of vertebral artery was performed in number, site and shape of ponticulus, we found that the ponticulus composite was 57.1% (12/21) and higher than ponticulus simple 32.8%(57/174)(χ² = 4.873, P = 0.027), the ponticulus borderline was 68.8% (11/16) which was also higher than ponticulus posticus (27.2%) and ponticulus lateralis (36.4%) in the ponticulus simple (χ² = 11.357, P = 0.030), the sharp ones (64.2%) were higher than the blunt(14.6%) in the tip of bony processes of the incomplete type ponticulus(χ² = 26.813, P = 0.001), the smaller ones were higher than the larger in the distance of the gap between the two tips of bony processes in the incomplete type ponticulus (χ² = 9.212, P = 0.010), and the smallerones (87.5%) were also higher than the larger (28.6%) in the diameter of the hole of complete type ponticulus(χ² = 18.193, P = 0.001), all of the above ones showed statistical significance among all groups by Chi-square test (P < 0.05). Conclusions: Ponticulus of atlas can significantly increase the risk of abnormal morphology of V3 segment of vertebral artery, and the differences of abnormality of vertebral artery were performed in number, site and shape of ponticulus, which included the ponticulus composite, ponticulus borderland, the shape tip of bony processes, the moderate distance between the two lip of bony processes, and the smaller diameter of complete type Ponticulus. (authors)