An evaluation of the reproducibility of landmark identification in traditional versus computer-assisted digital cephalometric analysis system

Abstract

Objective To determine the reliability of Computer Assisted Digital Cephalometric Analysis System (CADCAS) in terms of landmark identification on the values of cephalometric measurements in comparison with those obtained from original radiographs. Materials and Methods The study material consisted of Twenty five lateral cephalograms selected randomly, 16 cephalometric points together with 10 angular and 5 linear cephalometric measurements. The landmarks were manually picked on the tracing & the measurements of X &Y axis done with reference grid. The same tracing was digitized & image loaded in the software (ViewBox 3.1.1) was checked for the magnification (metal ruler) & distortion. The second part of the study compared manual and the CADCAS since the landmarks were manually digitized on screen as against the manually picked ones on the tracing paper. The x and y-coordinates for 16 landmarks were measured, mean and standard deviation calculated, linear and angular measurements compared. Statistical Analysis A paired t-test was done to calculate the statistical significance of the differences. Intraclass reliability coefficient (signifying reproducibility) of the variable was recorded. The observations were tabulated and analysis was done using the paired t test at a P value <0.05. Results Out of 47 variables looked for, 21 showed statistical significance. Direct digitization onscreen (CADCAS) was the quickest and least tedious method. CADCAS was unreliable with linear measurements involving bilateral structures such as Gonion & Articulare. Conclusions Both the methods are equally reliable and reproducible. The intra-class reliability coefficient of all variables differed only slightly, which is not clinically significant.