Observer reliability of three-dimensional cephalometric landmark identification on cone-beam computerized tomography

Abstract

To evaluate reliability in 3-dimensional (3D) landmark identification using cone-beam computerized tomography (CBCT). Twelve presurgery CBCTs were randomly selected from 159 orthognathic surgery patients. Three observers independently repeated 3 times the identification of 30 landmarks in the sagittal, coronal, and axial slices. A mixed-effects analysis of variance model estimated the intraclass correlations (ICC) and assessed systematic bias. The ICC was >0.9 for 86% of intraobserver assessments and 66% of interobserver assessments. Only 1% of intraobserver and 3% of interobserver coefficients were <0.45. The systematic difference among observers was greater in X and Z than in Y dimensions, but the maximum mean difference was quite small. Overall, the intra- and interobserver reliability was excellent. Three-dimensional landmark identification using CBCT can offer consistent and reproducible data if a protocol for operator training and calibration is followed. This is particularly important for landmarks not easily specified in all 3 planes of space.