基于三维重建骨盆模型的骨盆指数测量

Pelvic incidence measurement based on three-dimensional computed tomography pelvic reconstruction

目的介绍一种基于成人高分辨率骨盆CT数据三维重建骨盆模型测量骨盆指数(PI)的方法,并描述PI在样本人群中的分布特征及与年龄的相关性。方法回顾性收集上海交通大学医学院附属第九人民医院影像数据库中因非骨科疾患而行骨盆CT检查的304例成人患者数据,进行模型重建,利用最近点迭代法等算法确定前平面、中矢状面等参考面与相关骨性标志,完成PI测量。分析PI值在性别之间的差异及与年龄的相关性。使用简单随机抽样法选取30位研究对象的CT数据,通过计算组间和组内相关系数进行可靠性分析。结果 304例研究对象中,178例女性PI为46.03°±9.05°与126例男性的PI值(44.12°±8.04°)无差异(t=1.895,P=0.059)。PI与年龄在样本人群中存在较弱相关性(r=0.120,P=0.037)。小于40岁年龄组PI值为43.83°±7.33°显著小于40~80岁年龄组PI值(46.14°±9.35°)(t=-2.409,P=0.017)。对随机抽取的30例研究对象进行PI算法的可靠性研究显示,组内相关系数和组间相关系数分别为0.961 2(95%CI为0.891 7~0.989 3,P<0.001)和0.986 7(95%CI为0.961 1~0.996 4,P<0.001)。结论基于三维重建骨盆模型的PI测量方法具有较高的可靠性与精确性。在本研究样本人群中,PI无性别差异,与年龄有弱相关性,40~80岁个体PI值大于年轻个体PI值。

Objective To introduce a method of measuring pelvic incidence（PI） based on three-dimensional computed tomography （CT） pelvic reconstruction, and to analyse the distribution characteristics of PI in the sample population, and the correlation between PI and patient age.Methods A total of 304 adult patients receiving pelvic CT due to non-orthopaedic disorders in the Shanghai Ninth People′s Hospital Affiliated to Shanghai Jiaotong University School of Medicine were retrospectively included. The CT data were used to 3D reconstruct pelvic models. According to the interactive closest points algorism, hip axis and midpoint of the sacral endplate were calculated after anterior pelvic plane and mid-sagittal plane were determined. Differences in parameters between groups were evaluated, and the correlation between PI and age was analyzed. To quantify the method′s accuracy and reliability, a subgroup of 30 DICOM files was randomly selected to perform a validation study with intraobserver and interobserver correlation coefficients.Results PI between males （44.12°±8.04°） and females （46.03°±9.05°） was not significantly different （ t =1.895, P =0.059）. There was a weak correlation between PI and age in the whole group （ r =0.120, P = 0.037 ）. PI was larger in the group aged between 40-80 years（46.14°±9.35°）than the group aged below 40 years （43.83°±7.33°）. Reliablitiy study showed intraobserver correlation coefficient was 0.961 2 （95% CI 0.891 7-0.989 3, P 〈0.001）, and interobserver correlation coefficient was 0.986 7 （95% CI 0.961 1-0.996 4, P 〈0.001）.Conclusion Pelvic incidence measurement based on three-dimensional computed tomography pelvic reconstruction was reliable and accurate. In this study, we found no significant difference between male and female subjects in PI. There was a weak correlation between PI and age in the whole group and PI was significantly larger in the senior group aged 40 to 80 years than the young group below 40 years old.