Improving the accuracy of bone mineral density using a multisource CBCT

Abstract

Because of the inherent limitations, conventional cone beam computed tomography (CBCT) systems are inaccurate in quantifying bone mineral density (BMD). A multisource CBCT (ms-CBCT) was recently developed. The aim of this study was to evaluate the accuracy of the ms-CBCT system in estimating the BMD of mandibular and maxillary bones and to compare it with the conventional CBCT, utilizing a multi-detector CT (MDCT) as a reference standard. For this purpose, an anthropomorphic adult skull and tissue equivalent head phantom, along with a homemade calibration phantom containing inserts of calcium hydroxyapatite of varied densities, were imaged. The phantoms were imaged using the ms-CBCT, the ms-CBCT operating in the conventional CBCT mode using one source, two clinical dental CBCT scanners, and an MDCT, under similar imaging doses. The images were reconstructed, registered and segmented. The scanner-specific calibration curves were utilized to establish a relation to convert the measured CT Hounsfield Unit (HU) and Greyscale Value (GV) at multiple region-of-interests to the BMD. Statistical analysis showed that a significant enhancement in the accuracy of the HU and BMD values derived from the ms-CBCT as compared to the conventional clinical dental CBCT. These findings suggest that the ms-CBCT system may serve as a reliable and lower-dose alternative for precise BMD quantification.