Muramatsu Atsushi, Nawa Hiroyuki, Kimura Momoko, Yoshida Kazuhito, Maeda Masahito, Katsumata Akitoshi, Ariji Eiichiro, Goto Shigemi
Department of Orthodontics, Aichi-Gakuin University School of Dentistry, Nagoya, Japan.
Angle Orthod. 2008 May;78(3):396-402. doi: 10.2319/040207-166.1.
To assess the plotting reproducibility of landmarks on 3-dimensional computed tomography (3D-CT) images through use of the 95% confidence ellipse in order to propose sufficiently stable coordinate systems for 3D-CT measurements.
Six dentists plotted 19 landmarks twice on 3D-CT images. Scatterplots and the 95% ellipses were produced 3-dimensionally, and the areas of the ellipses were calculated for evaluating the reproducibility of landmarks.
The plotting reproducibility of each landmark showed characteristic features. Among five landmarks (the sella [S], nasion [N], basion [Ba], orbitale [Or], and true porion [Po]) that are frequently used as reference points on cephalograms, Ba showed the smallest areas for all three coordinate axes, indicating high reproducibility. The coronoid process (CP) and the tooth-related landmarks showed relatively high reproducibility.
Sufficiently stable coordinate axes could be proposed for different treatments and studies.
通过使用95%置信椭圆评估三维计算机断层扫描（3D-CT）图像上标志点的绘图再现性，以便为3D-CT测量提出足够稳定的坐标系。
六名牙医在3D-CT图像上对19个标志点进行了两次绘制。三维生成散点图和95%椭圆，并计算椭圆面积以评估标志点的再现性。
每个标志点的绘图再现性呈现出特征。在头影测量中常用作参考点的五个标志点（蝶鞍[S]、鼻根点[N]、颅底点[Ba]、眶点[Or]和真性耳点[Po]）中，Ba在所有三个坐标轴上的椭圆面积最小，表明再现性高。冠突（CP）和与牙齿相关的标志点显示出相对较高的再现性。
可为不同的治疗和研究提出足够稳定的坐标轴。
