D113. Comparison of Methodologies for Craniofacial Soft-tissue Cephalometrics: The Value of Virtual Reality

Abstract

PURPOSE: Myriad options are available for soft-tissue analysis, which is vital to perioperative evaluation and research. Our objective is to compare accuracy, precision, and costs of available cephalometric modalities using facial soft-tissue measurements. METHODS: Twenty soft-tissue facial measurements were performed by 5 measurers of varying experiences on 5 adult subjects, using 6 methods - manual calipers, cone-beam CT, virtual reality (VR), 3D photogrammetry, iPad-based 3D photogrammetry, and 2-dimensional photos. Measurement sessions were timed and performed in triplicate, for a total of 9000 measurements. Intraclass correlation coefficient (ICC) was calculated for accuracy and one-way ANOVA was used for comparison. Coefficient of variation was compared among groups to evaluate precision of different methods, considering caliper measurements as the gold standard. RESULTS: ICC among raters was 0.932, indicating excellent reliability. VR was significantly faster than others (137 s vs 217 s for caliper, p<0.001). Coefficient of variation was highest for 2D photographs and lowest for VR (6.4 vs 11.0, p<0.001). The coefficient of variation of caliper was similar to all methods, except 2D photography which was significantly worse. Measurements with the greatest absolute difference from caliper measurements, across modalities, were those around the eyes (left to right exocanthion), tragion to antitragion, and tragion to exocanthion. CONCLUSION: 2D photography is not an accurate way for cephalometric measurements. Virtual reality is the fastest, has the lowest variation between measurements, and is equivalent to caliper measurements. For studies involving a large amount of cephalometrics, virtual reality measurements may be a good option to improve study throughput.