Imaging anatomy and research of ponticulus posticus with three-dimensional CT

Objective To use three-dimensional CT display ponticulus posticus(PP), make the classification and measurement of PP, and provide the anatomical basis for the related application. Methods A total of 63 cases of PP were found from CT angiography(CTA)of head and neck in our hospital of PACS system from January 2008 to December 2014.On the three-dimensional images, these parameters of PP were measured, including the anteroposterior diameter(AD), vertical diameter(VD), breakpoint distance(BD), third segment diameter of VA(D-VA), the distance between peak of groove ring and occipital(D-RO), the distance of groove ring to midline diameter(D-RL), distance from posterior arch nodule of atlas to the occipital bone(D-NO). Results Three-dimensional CT found the PP in 63 cases with 104 sides, which male of 53 cases, female of 10 cases, left side PP of 49 sides, including the complete type of 23 sides and incomplete type 26 and the right PP of 55 sides, including complete type 22 sides and incomplete type 33.In the left PP, measurements of AD, VD, BD, D-VA, D-RO, D-NO and D-RL were(5.02±1.17)mm, (3.59±1.26)mm, (3.91±2.51)mm, (3.88±0.78)mm, (2.15±2.58)mm, (18.62±3.01)mm and(5.19±3.32)mm, respectively, the right PP were(5.13±1.29)mm, (3.87±0.88)mm, (4.02±2.77)mm, (3.59±0.89)mm, (2.14±2.63)mm, (4.89±3.36)mm, (18.89±3.74)mm and(4.8±3.36)mm, respectively.Statistical comparison showed that AD of PP was greater than VD, D-VA, bilateral BD of PP was greater than that of the unilateral and D-VA, while unilateral BD of PP was less than D-VA, VD, D-RL of complete type PP were less than that of incomplete, D-RO, D-NO of complete type PP were greater than that of incomplete. Conclusion CT three-dimensional imaging can clearly and directly display the PP.Incidence of PP in the male is more than the female.The typing, incidence, size and shape of PP in the left are similar the right.AD of PP is greater than VD, which may limit the VA activities in vertical direction, especially that of complete PP.The PP opening of incomplete type in the bilateral is larger than in the unilateral, which may relate to the degree of degradate evolution. Key words: Ponticulus posticus; Vertebral artery; Anatomy measurement; Three-dimensional CT