Accuracy and Reliability of Ultra Low Dose CBCT Versus CBCT Imaging in Semi-Automated Segmentation of the Mandibular Condyle (A Diagnostic Accuracy Study)

Abstract

Aim: The aim of this study was to evaluate the effect of conventional or ultra-low dose CBCT imaging on the accuracy of semi-automated segmentation of the mandibular condyles, and their effect on volumetric measurements when compared to the actual volumetric measurements of the mandibular condyles as a gold standard.

Methodology: Dry human skulls and dry human mandibles were recruited from the Anatomy Department, Faculty of Medicine, Cairo University. Gutta-percha points were secured horizontally parallel to the lowest part of the sigmoid notch all around the mandibular condyles to locate the condylar area for volumetric assessment. Reference standard for mandibular condyle volumes was calculated by using the Archimedes Principle.The dry skulls and mandibles were scanned in the Oral and Maxillofacial Radiology Department, Faculty Dentistry, Cairo University; using CBCT machine Planmeca ProMax® 3D Mid, using two scan protocols; conventional and ultra-low dose. After applying the index test, DICOM files of both CBCT conventional and ultra-low dose CBCT scanning protocols were imported from Romexis software (Romexis® software (Planmeca- Helsinki-Finland) to 3D slicer free segmentation software and semi-automated segmentation was performed. Volumetric measurements were calculated on the segmented condyles by 3D slicer software and compared to the real gold standard measurements.

Results: There was no clinical significant difference between the volumetric measurements obtained from the semi-automated segmented condyles scanned by using ULD CBCT protocol, in comparison to the measurements obtained from conventional CBCT scanning protocols, as well as the actual real gold standard measurements.

Conclusion: ULD scanning protocols should be considered effective when mandibular condyle semi-automated segmentation to be performed. 3D slicer software is an accurate and reliable free segmentation software for maxillofacial structures segmentation, especially mandibular condyles.