Three-dimensional fetal cephalometry: An evaluation of the reliability of cephalometric measurements based on three-dimensional CT reconstructions and on dry skulls of sheep fetuses

Aim: To develop a 3D CT cephalometric analysis for maxillary growth evaluation of sheep fetuses operated in utero, and to evaluate the reliability of this analysis by comparing it with a direct cephalometric analysis on dry skulls. Material and methods: Five skulls of operated sheep fetuses were used, which after preparation were CT scanned and a 3D reconstruction was performed. A cephalometric analysis was performed directly on the dry skulls as well as on the reconstructed 3D CT images. In total, 56 linear distances were measured. In order to access the error of the method, the procedure was repeated after a 2 week interval. Results: The comparison between the direct cephalometric and the 3D CT analysis revealed that only 5 variables were significantly different. The evaluation of the error of method revealed that 7 variables of the direct cephalometric analysis and none of the 3D CT analysis differed significantly. Conclusions: According to the results of this study, it can be concluded that a cephalometric analysis on 3D CT reconstructed images of the skulls includes fewer identification errors and seems to be an accurate and reliable method that could be regarded at least as equivalent to conventional cephalometry.