常用正颌外科三维头影测量标志点的可重复性研究

目的 研究正颌外科手术中常用软硬组织三维头影测量标志点的可重复性,为精确的正颌外科三维头影测量提供参考依据.方法 选取59名颅颌面骨骼及咬合关系正常的志愿者拍摄螺旋CT,并三维重建.由同一研究者选取54个头影测量标志点进行定点测量,共3次,每次间隔一周.共定点3186个,每个点包括x,y,z三个坐标数据,共获取数据9558个.采用组间相关系数（InterclassCorrelation,ICC）进行一致性检验,研究每个标志点测量的可重复性.结果 86.5％的标志点ICC值大于0.9,其中硬组织标志点与软组织标志点分别为86.4％和87.0％.软硬组织标志点在各个轴向定点的可重复性最好的是上下方向,最差的是前后方向.结论 计算机三维头模上软硬组织标记点的确定具有较高的可重复性,能准确地反映头颅软硬组织的真实情况.

Reproducibility of landmarks on three-dimensional cephalometric analysis for orthognathic surgery

Objective To study the Reproducibility of landmarks of soft and hard tissueso as to provide reference to accurate three-dimensional cephalometric analysis for orthognathic surgery. Methods The study population consisted of 59 volunteers examined with spiral 3D computed tomography （CT）. For each analysis, 54 cephalometric reference landmarks were identified on the three spatial axes（x, y, z）. All the identifications were performed by the same observer. This was repeated three times during 3 sessions at least 1 week apart. In total, 3186 imaging measurements were taken,as each determination has 3 coordinates, 9558 data were processed with SASg. 2 statistical package. To discover the reproducibility of the method on landmark location, an ICC was undertaken using one variation factors： time （t1, t2 and t3） for each axis （x, y, z） and landmark. Results The ICC was〉0. 9 for 86.48X of all the landmarks,which with high reliability. The ICC was 〉0. 9 for 86.38 ~of the hard tissue landmarks, and for 87 G of the soft tissue landmarks. The reproducibility of landmarks in three axis was z〉x〉y. Those with lower ICC were Me＊ , Zy＊ R, Zy＊ L and ZyL. Conclusions Three dimensional landmark identification using CT can offer consistent and reproducible data so as to create cephalometric analyses reflectingthe 3D reality.