Comparison of measurements from digital cephalometric radiographs and 3D MDCT-synthetized cephalometric radiographs and the effect of head position / 대한구강악안면방사선학회지

ABSTRACT

PURPOSE: To investigate the reproducibilities and compare the measurements in digital and MDCT-synthesized cephalometric radiograph, and to investigate the effect of head position on the measurement during imaging with MDCT. MATERIALS AND METHODS: Twenty-two dry skulls (combined with mandible) were used in this study. Conventional digital cephalometric radiograph was taken in standard position, and MDCT was taken in standard position and two rotated position (10degrees left rotation and 10degrees right tilting). MDCT data were imported in OnDemand(R) and lateral cephalometric radiograph were synthesized from 3D virtual models. Two types of rotated MDCT data were synthesized with default mode and with corrected mode using both ear rods. For all six images, sixteen angular and eleven linear measurements were made in V-Ceph(R) three times. Reproducibility of measurements was assessed using repeated measures ANOVA and ICC. Linear and angular measurements were compared between digital and five MDCTsynthesized images by Student t-test. RESULTS: All measurements in six types of cephalometric radiograph were not statistically different under ICC examination. Measurements were not different between digital and MDCT-synthesized images (P>.05). Measurements in MDCT-synthesized image in 10degrees left rotation or 10degrees right tilting position showed possibility of difference from digital image in some measurements, and possibility of improvement via realignment of head position using both ear rods. CONCLUSION: MDCT-synthesized cephalometric radiograph can substitute conventional cephalometric radiograph. The error on head position during imaging with MDCT have possibility that can produce measurement errors with MDCT-synthesized image, and these position error can be corrected by realignment of the head position using both ear rods.