Continuous measurement of the mandibular cortical bone in dental panoramic radiographs for the diagnosis of osteoporosis using a clustering algorithm on histograms

This study aimed to realize a newly developed method of continuous measurements of the cortical width of the lower border of the mandible, between the upper and lower margins of the cortical bone to identify women with low bone mineral density (BMD) or osteoporosis. An automatic clustering algorithm is applied to obtain a robust estimate of the cortical width. This continuous measurement method provides more accurate cortical width than the conventional one-point method. The system's efficacy in identifying low BMD at the lumbar spine and femoral neck in 100 postmenopausal women (≥50 years) with no history of osteoporosis was evaluated. The mandibular cortical width below the mental foramen was measured by enhancing the original image of the panoramic radiograph, determining cortical boundaries and evaluating the distance between boundaries continuously, by applying the clustering algorithm to a significant portion of the histogram. It is experimentally shown that the improved sensitivity and specificity provided more stable and significant diagnostic accuracy than the conventional one-point method.