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

This study demonstrated the feasibility of obtaining mandible bone mineral density (BMD) scores using spectral panoramic imaging.

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).

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.

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.