Dolphin Imaging Software: An analysis of the accuracy of cephalometric digitization and orthognathic prediction

The purpose of this study was to examine and compare the reproducibility and reliability of digitization using Dolphin Imaging Software (Version 8.0) with traditional manual techniques. In addition, orthognathic prediction was compared with actual outcomes. Sixty lateral cephalograms were evaluated by two methods: manual tracing and indirect digitization using Dolphin Imaging Software (Version 8.0). Method error (reliability) using duplicate measurements for each method, and comparison of both techniques (reproducibility), were investigated using alternative statistical methods, Bland and Altman (1986) and Lin's Correlation of Concordance (1989). Each technique was significantly reliable at the 95% level (method error). Comparing the standard deviations of the differences, manual tracing proving more reliable for SNA (1.36° manually, 2.07° digitally), SNB (1.19° and 1.69°), SNMx (1.39° and 2.66°), and MxMd (1.77° and 2.26°), and Dolphin digital tracing more reliable for UIMx (3.49° digitally and 3.97° manually) and LIMd (2.90° and 3.04°). However, systematic error in the software's calculation of LAFH% resulted in measurements 4% larger than manual techniques, a difference which is clinically significant. Comparison of actual outcome and software generated prediction for 26 orthognathic cases demonstrated clinically significant differences for all measurements (ρc 0.32 for ANB to 0.91 for LIMd; P < 0.05). The investigation revealed the impact of radiographic magnification when used in an uncalibrated system. These findings indicate that Version 8.0 of Dolphin Imaging Software needs to be re-assessed for software errors that may result in clinically significant miscalculations, and to facilitate compensation of radiographic magnification when using linear measurements.