A comparison of manual traced images and corresponding scanned radiographs digitally traced

The aim of this study was to compare the accuracy of cephalometric measurements made with digital tracing software (FACAD) with equivalent hand-traced measurements, and to evaluate the reproducibility of each method. Pre- and post-surgical lateral cephalographs of 30 adult patients (12 males and 18 females, median age = 25 years, standard deviation = 8.7) who had undergone orthognathic treatment were scanned into a computer. One operator identified 25 landmarks digitally on the computer display and manually on acetate paper. Measurements on the 60 radiographs were duplicated, and measurement error of each method was determined with interclass correlation. A paired t-test was used to detect differences between the manual and digital methods. Overall, greater variability in digital cephalometric measurements was found. Differences in Gn', Li, Si, and Ii-Li measurements between the two methods were statistically (P < 0.05), but not clinically significant. The findings indicate that the results of the two investigated tracing methods are similar and that digital tracing with FACAD is reliable and can be used routinely.