Evaluating Diagnostic Efficacy of Cone Beam Computed Tomography Performed in Different Imaging Conditions Based on Field of View and Resolution in the Detection of Mandibular Condyle Erosions: An In Vitro Study

Background: New cone beam computed tomography (CBCT) devices have the ability to take images with different fields of views (FOVs) and resolutions. The larger the FOV and the higher resolution of the image, the higher the patient’s dose would be. Objectives: This research aims to analyze the diagnostic accuracy of FOV’s different dimensions and the various resolutions in the diagnosis of mandibular condyle erosions. Materials and Methods: CBCT images using NewTom VGi (Verona, Italy) system in five different FOVs and resolutions (voxel size) were taken from eight human dried mandibles in which the erosion-like lesions were created on both condyles. Imaging was performed before and after the formation of erosion; afterwards, the images were evaluated by two maxillofacial radiologists to analyze the absence or presence of the lesions. Resultant data was evaluated by SPSS V. 22.0, McNemar and Kappa statistical methods. Results: The highest sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were attributed to 8 × 8 FOV and the lowest was attributed to 12 × 8 FOV. In analyzing different resolutions, the highest sensitivity, specificity, PPV, and NPV were attributed to high resolution (0.125 and 0.15 mm voxel size). There was no statistically significant difference between sensitivity, specificity, PPV, and NPV of different FOVs and different resolutions. Inter-observer and intra-observer cofficiency were at excellent range. Conclusion: Considering there was no significant difference between the results, it is possible to use voxels in larger size to reduce patient’s dose in order to detect mandibular condyle erosions. In addition, FOV with lower patient’s dose is the method of choice.