Chien P C, Parks E T, Eraso F, Hartsfield J K, Roberts W E, Ofner S
Department of Orthodontics and Oral Facial Genetics, Indiana University Shool of Dentistry, Indianapolis, IN, USA.
Dentomaxillofac Radiol. 2009 Jul;38(5):262-73. doi: 10.1259/dmfr/81889955.
To compare reliability for landmark identification on patient images from three-dimensional (3D) cone beam CT (CBCT) and digital two-dimensional (2D) lateral cephalograms.
Ten lateral cephalometric digital radiographs and their corresponding CBCT images were randomly selected. 27 observers digitally identified 27 landmarks in both modes. The x- and y-coordinates for each landmark, indicating the horizontal and vertical positions, were analysed for interobserver reliability by comparing each measurement to the best estimate of the true value. Intraobserver reliability was also assessed. Linear models and intraclass correlation coefficients (ICCs) were used for analyses.
For interobserver reliability, the following locations were farther from the best estimate for 2D than 3D: x-location in subspinale (A-point), anterior tip of the nasal spine (ANS), L1 lingual gingival border and L1 root; y-location in porion, ramus point and orbitale; x- and y-locations in basion, condylion, midramus, sigmoid notch and U6 occlusal. 3D y-locations were farther in the gonion, L1 tip, sella and U1 tip. For intraobserver reliability, 2D locations were farther in y-locations in orbitale and sigmoid notch, and both x- and y-locations in basion. 3D locations were farther in the x-location in U1 labial gingival border and y-locations in L1 tip, L6 occlusal, menton and sella. For intraobserver ICCs, greater variations in 2D than 3D included: A-point, ANS, midramus, orbitale, ramus point, sigmoid notch and U1 root.
3D imaging, as in CBCT, allows for overall improved interobserver and intraobserver reliability in certain landmarks in vivo when compared with two-dimensional images.
比较在三维(3D)锥形束CT(CBCT)和数字化二维(2D)头颅侧位片上对患者图像进行标志点识别的可靠性。
随机选取10张头颅侧位数字化X线片及其对应的CBCT图像。27名观察者在两种模式下对27个标志点进行数字化识别。通过将每个测量值与真实值的最佳估计值进行比较,分析每个标志点的x和y坐标(分别表示水平和垂直位置)的观察者间可靠性。同时也评估了观察者内可靠性。采用线性模型和组内相关系数(ICC)进行分析。
对于观察者间可靠性,与3D相比,2D中以下位置离最佳估计值更远:棘下点(A点)的x位置、鼻棘前端(ANS)、L1舌侧牙龈边缘和L1牙根;耳点、升支点和眶点的y位置;颅底点、髁突点、升支中部、乙状切迹和U6咬合面的x和y位置。3D中,角点、L1尖端、蝶鞍和U1尖端的y位置离最佳估计值更远。对于观察者内可靠性,2D中眶点和乙状切迹的y位置以及颅底点的x和y位置离最佳估计值更远。3D中,U1唇侧牙龈边缘的x位置以及L1尖端、L6咬合面、颏下点和蝶鞍的y位置离最佳估计值更远。对于观察者内ICC,2D比3D变化更大的包括:A点、ANS、升支中部、眶点、升支点、乙状切迹和U1牙根。
与二维图像相比,CBCT等三维成像在体内某些标志点的观察者间和观察者内可靠性方面总体上有所提高。