Objective To expand MSCT obseration and cognition in the ponticulus of atlas,and to improve the diagnosis for it. Methods 263 cases were collected among the patients undergone the examine of MSCT angiography in intracranial and cervical and volume rendering technique(VRT)with unenhance images,and observation and analysis was focused on the posterior arch of atlas. Results 69 cases(97 sides)were detected ponticulus in this group,including unilateral in 41 cases,bilateral in 28 cases.The simple type ponticulus were 82 sides,including the ponticulus posterior (PP)were 60 sides,the ponticulus lateralis (PL)were 1 5 sides,the ponticulus borderland (PB)were 5 sides,The ponticulus middle (PM)were 2 sides.According to the shape of the ponticulus:simple root in 43 sides,opposite beaked in 21 sides,complete type in 18 sides.The ponticulus compound (PC)were 1 5 sides.Conclusion The images of MSCT VRT can showed accurately the ponticulus of atlas,and it can provide reliable imaging evidence on its diagnosis and classification,and it can be used as an unearthly method for its examination.

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 byχ2 test. Results A total of 195 sides (157 cases) ponticulus were detected in 613 cases (1 226 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% (103/1 226), combination ponticulus was 35.4% (69/195), uncombination ponticulus was 3.3%(34/1 031), 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 performanced 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 borderl 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.

Objective To explore the belongingness,name and clinical significance of a sort of osteal structure variation (OSV) posterior,outboard and superior to the ditch of vertebral artery of atlas.Methods 23 cases of OSV were collected among 426 patients underwent MSCT intracranial and cervical angiography with volume rendering technique (VRT)to notice the pier point,shape and direction of protuberance,and the relation and influence to the vertebral artery.Results The incidence of OSV was 5.40%(23/426) in which 31 sides were detected,and 1 5 cases in unilateral and 8 cases in bilateral.Simple type was showed at 1 9 sides,compound type at 12 sides with other ponticulus.According to the shape of the ponticulus,simple root was seen at 1 7 sides(13 inferior root and 4 lat-erial root),opposite beaked at 5 sides,complete type at 9 sides.OSV was located at posterior,outbord and superior to the ditch of vertebral artery of atlas and closed to the vertebral artery.The vertebral artery was influenced by OSV as following:in simple OSV vertebral artery stenosis was seen at 4 sides in which unite convulsion was showed at one side;in compound OSV vertebral artery ste-nosis was seen at 5 sides,in which unite convulsion was showed at 2 sides.Conclusion OSV is similar to ponticulus posticus(PP)and ponticulus lateralis(PL),and has similarly importance clinical significance,and should belong to the ponticulus of atlas,and to be named as ponticulus borderland(PB).