Influência de protocolos de aquisição de imagens de tomografia computadorizada de feixe cônico na avaliação volumétrica de cabeças da mandíbula

Abstract

The condyle is a bony structure that serves as the primary growth center of the mandible. Due to its anatomical intricacy, the assessment of bone through cone beam computed tomography (CBCT) may be warranted. Typically, several CBCT acquisition protocols are available, and it is imperative to choose the ones most aligned with clinical requirements and the anatomical characteristics of the region of interest. The utilization of low radiation dose protocols can introduce noise and reduce image quality, potentially impacting the accuracy of volumetric measurements of this structure. Hence, the objective of this study was to assess whether variations in milliamperage and voxel size values can exert an influence on the volumetric measurements of mandibular condyles in CBCT examinations. CBCT images of 36 temporomandibular joints (TMJs) from 18 dry skulls and their corresponding mandibles were acquired using two different milliamperage settings (4.5 and 6.3 mA) and varying voxel sizes (0.085, 0.125, and 0.280 mm), resulting in a total of 216 images. These images were exported in DICOM format and subsequently assessed using the ITK-SNAP® software by two independently trained evaluators. Inter- evaluator agreement demonstrated an excellent level of concordance with a coefficient of 0.904. No statistically significant differences in condylar volume were observed among the different milliamperage values and voxel sizes employed (p>0.05). Therefore, the milliamperage values and voxel size did not influence the volumetric evaluation of maintenance heads on the tested device. This study suggests that tomographic protocols employing lower radiation doses, as used in this investigation with lower voxel values and larger voxel sizes, should be considered for the evaluation of condylar volume.