Thesis (M.Sc.) - Cairo University - Faculty of Oral and Dental Medicine- Department of Oral (Radiology daignosis)

Accurate volumetric measurements have become an important requirement in most of dental branches. The aim of this study to evaluate the accuracy of the volumetric measurement acquired from CBCT images. The study was conducted on 14 dry human skulls, 28 maxillary sinuses of dry human skull. The skulls were scanned using Planmeca Promax 3DMID CBCT and volumetric segmentation was conducted using Planmeca Romexis viewer. The physical volume of the sinuses was determined indirectly using water displacement technique following Arquimedes principle. The volumes of the maxillary sinuses obtained from manual segmentation of CBCT were compared with their volumes obtained by water displacement technique. Statistical analysis showed excellent reliability of 0.989 between the mean volumetric measurements of the maxillary sinus obtained by manual segmentation and the mean of the real measurements on dry skull with 95% confidence limits of 0.98 and 0.994. Within the limitations of this study, the following could be concluded: Manual segmentation of volumetric measurements should be further enhanced for better time and workflow management if it is intended for everyday use of volume calculation. 1-Modifications in the Planmeca Romexis viewer3.1.8 R software are strongly required in terms of changing the circular area tracing region into a point or line to eliminate masking of the underlying structure to be traced after aiming of the area. This certainly will allow better tracing and easier checkup of the segmented volume. 2-Correction tools should be added to allow adjustments of the finally segmented volume either by erasing or adding excess.

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