Dot Gauthier, Rafflenbeul Frédéric, Kerbrat Adeline, Rouch Philippe, Gajny Laurent, Schouman Thomas
Institut de Biomecanique Humaine Georges Charpak, Arts et Metiers Paristech, 75013 Paris, France.
UFR d'Odontologie, Universite de Paris, 75006 Paris, France.
J Clin Med. 2021 Nov 15;10(22):5303. doi: 10.3390/jcm10225303.
In some dentofacial deformity patients, especially patients undergoing surgical orthodontic treatments, Computed Tomography (CT) scans are useful to assess complex asymmetry or to plan orthognathic surgery. This assessment would be made easier for orthodontists and surgeons with a three-dimensional (3D) cephalometric analysis, which would require the localization of landmarks and the construction of reference planes. The objectives of this study were to assess manual landmarking repeatability and reproducibility (R&R) of a set of 3D landmarks and to evaluate R&R of vertical cephalometric measurements using two Frankfort Horizontal (FH) planes as references for horizontal 3D imaging reorientation. Thirty-three landmarks, divided into "conventional", "foraminal" and "dental", were manually located twice by three experienced operators on 20 randomly-selected CT scans of orthognathic surgery patients. R&R confidence intervals (CI) of each landmark in the -x, -y and -z directions were computed according to the ISO 5725 standard. These landmarks were then used to construct 2 FH planes: a conventional FH plane (orbitale left, porion right and left) and a newly proposed FH plane (midinternal acoustic foramen, orbitale right and left). R&R of vertical cephalometric measurements were computed using these 2 FH planes as horizontal references for CT reorientation. Landmarks showing a 95% CI of repeatability and/or reproducibility > 2 mm were found exclusively in the "conventional" landmarks group. Vertical measurements showed excellent R&R (95% CI < 1 mm) with either FH plane as horizontal reference. However, the 2 FH planes were not found to be parallel (absolute angular difference of 2.41°, SD 1.27°). Overall, "dental" and "foraminal" landmarks were more reliable than the "conventional" landmarks. Despite the poor reliability of the landmarks orbitale and porion, the construction of the conventional FH plane provided a reliable horizontal reference for 3D craniofacial CT scan reorientation.
在一些牙颌面畸形患者中，尤其是接受外科正畸治疗的患者，计算机断层扫描（CT）有助于评估复杂的不对称情况或规划正颌手术。对于正畸医生和外科医生来说，三维（3D）头影测量分析能使这种评估变得更容易，这需要确定标志点的位置并构建参考平面。本研究的目的是评估一组3D标志点的手动标志点定位的重复性和再现性（R&R），并使用两个法兰克福平面（FH）作为水平3D成像重新定向的参考，评估垂直头影测量的R&R。33个标志点分为“传统”、“孔性”和“牙性”三类，由三名经验丰富的操作人员在20例随机选择的正颌手术患者的CT扫描图像上手动定位两次。根据ISO 5725标准计算每个标志点在-x、-y和-z方向上的R&R置信区间（CI）。然后使用这些标志点构建2个FH平面：一个传统的FH平面（左侧眶点、右侧和左侧耳点）和一个新提出的FH平面（内耳道中点、右侧和左侧眶点）。使用这2个FH平面作为CT重新定向的水平参考，计算垂直头影测量的R&R。仅在“传统”标志点组中发现重复性和/或再现性的95%CI>2mm的标志点。以任一FH平面作为水平参考，垂直测量均显示出极好的R&R（95%CI<1mm）。然而，未发现这2个FH平面平行（绝对角度差为2.41°，标准差为1.27°）。总体而言，“牙性”和“孔性”标志点比“传统”标志点更可靠。尽管眶点和耳点标志点的可靠性较差，但传统FH平面的构建为3D颅面CT扫描重新定向提供了可靠的水平参考。
