CT Anatomic Measurement Of Ponticulus Posticus And Medical Imaging Comparison

Objective To display the ponticulus posticus(PP) with X-ray, CT and MRI, and make a comparison in three imaging technology; to have the PP classification and imaging anatomy measurement, to provide the anatomical basis for the related clinical application.Methods 447 patients with PP were from PACS in our hospital from January 2008 to May 2015, of which 380 cases were found by X-ray, 63 cases by CT angiography(CTA) and 15 cases by MRI. Imaging data of 63 cases have be done the three-dimensional imaging to display and measure the PP, the parameters include the anteroposterior diameter of PP(AD), vertical diameter(VD), breakpoint diameter(BD) and the diameter of third segment vertebral artery(D-VA) and so on,and related data in statistical t test.Results There are 447 patients with PP, of which 380 cases found by X-ray, 204 cases in male and 176 in female; 63 cases by CTA, male 53 cases and female10, 15 cases by MRI, 8 cases in male and 7 in female; Among them, 16 cases of PP were found in 0-10 years old, and 0 cases were complete PP. Three dimensional CT imaging clearly showed the location, shape and size of PP, and space relationship of stereoscopic display and vertebral artery; The complete type,The first half of the ring, After half a ring, broken ring PP are respectively 55 sides,44 sides,3 sides,12 sides; The left and right ponticulus posticus of measurement values AD, VD, BD, D-VA are respectively 5.02±1.17mm、3.59±1.26 mm、3.91±2.51 mm、3.88±0.78 mm;5.13±1.29 mm、3.87±0.88 mm、4.02±2.77 mm、3.59±0.89 mm;The statistical comparison found that PP of AD is greater than VD、D-VA,bilateral PP of BD is greater than the unilateral,bilateral PP of BD is greater than D-VA,unilateral PP of BD is less than D-VA, complete type of PP of VD、D-RL is less than the incomplete type, complete type of PP of D-RO、D-NO is greater than the incomplete type.Conclusion Imaging examination is beneficial to find the existence of PP, 3D-imaging can clearly and directly display and measure the PP. Incidence of PP is more in the male than in the female. Most of patients with PP are at 41 to 50 years old and the complete PP is more than the incomplete, patients with incomplete PP are under 10 years old, that may speculated that it may be related to ossification of atlanto-occipital membrane and atlanto-occipital ligament. AD of PP is greater than VD of PP, which can limit the VA activity, especially in the complete PP. the large opening is find in the bilateral incomplete PP, which may related to the evolution of degradation. Measurements of PP will provide anatomical foundation for the study on the surgery of atlantoaxial joint and blood supply of vertebral artery.