The Reliability of 3D CT Analysis for Facial Asymmetry

ABSTRACT

3-dimensional computed tomography(3D-CT) imaging has been used in the diagnosis and surgical treatment planning of patients with craniofacial deformities, but its measurements were not commonly accepted contrary to the measurements in cephalometric analysis which was accepted as the best way to evaluate the facial profile on craniofacial & orthognathic fields. The purpose of this study was to compare the measurements from cephalometric analysis and 3D-CT analysis in facial asymmetric patients in order to show the reliability of the latter. 10 facial asymmetry patients had taken both cephalometry x-ray & 3D-CT. The 8 measurements were obtained from cephalometric analysis and 3D-CT analysis on each patient. The cephalometric analysis was based on the manual tracing of PA cephalometry x-ray film and the 3D-CT analysis was performed using the 'measuring tools' of Medical PACS system. The measurements included the maxillar & mandibular height, mandiblular body length, and vertical & horizontal deviation degree of maxilla and mandible. The paired t-test was used to compare differences between measurements from two methods. And also the ratio(affected side/unaffected side) in 3 measurements was calculated and compared using paired t-test to show the reliability. There were no statistically significant differences between measurements from cephalometric analysis and 3D-CT analysis(P > 0.05) except mandibular body length. Also no statistically significant differences were noted between the ratio of 3 measurements on cephalometric analysis and 3D-CT analysis(P > 0.05). 3D-CT analysis of facial asymmetry presents reliable data as much as cephalometric analysis. Moreover, it is very easy and simple method to use. The 3D-CT analysis as described herein is a practical method of evaluation the morphology of facial asymmetry and can replace the cephalometric analysis.