Mandible bone mineral density estimation using spectral panoramic X-ray imaging

Purpose: This study demonstrated the feasibility of obtaining mandible bone mineral density (BMD) scores using spectral panoramic imaging. Materials and Methods: Areal BMD scores were measured from the body and angle of the mandible in 3 anthropomorphic head phantoms using a spectral panoramic system (Planmeca Promax Mid, Planmeca Oy, Helsinki, Finland) equipped with a DC-Vela detector (Varex Imaging Corporation, Salt Lake City, USA). These results were compared to synthetic panoramic images generated from dual-energy CT acquisitions. Reproducibility was evaluated by repeatedly scanning 1 phantom with minor patient positioning errors, and the linearity of the BMD scores was assessed using calcium inserts in a Gammex 472 phantom (Sun Nuclear, Melbourne, USA). Results: The experimental and synthetic panoramic images appeared visually similar. The mean synthetic score was 0.640 g/cm², and the anthropomorphic phantoms produced a root mean squared error of 0.0292 g/cm² with a correlation coefficient of 0.969. Typical patient positioning errors did not substantially increase the error, which measured 0.0296 g/cm² and 0.0474 g/cm² for the left and right sides, respectively. Linearity tests using the Gammex phantom yielded a correlation coefficient of 0.998 for BMD scores ranging from 0.03 to 2.7 g/cm². Conclusion: The BMD data obtained from spectral panoramic imaging are consistent with both dual-energy CT and Gammex phantom measurements. Consequently, spectral panoramic imaging shows potential as a method for osteoporosis screening, leveraging the widespread use of panoramic imaging.