Abstract

Objectives: Recent studies suggest mandibular inferior cortical erosion visually determined on panoramic radiographs may be useful as an indicator of low skeletal bone mineral density (BMD) in women. Our purpose of this study was to develop computer - aided diagnosis (CAD) system that automatically determines mandibular cortical erosion on panoramic radiographs, and to estimate the validation of CAD system for the identification of women with low skeletal BMD.

Methods: Two hundred panoramic radiographs of postmenopausal women who had BMD assessments at the lumbar spine and the femoral neck by dual energy X - ray absorptiometry were used for this study. CAD system was constructed by mathematical morphology. One hundred panoramic radiographs were used for the development of CAD system in order to identify women with low skeletal BMD, and another 100 panoramic radiographs were used to estimate the validation of CAD system. Low skeletal BMD was defined as a BMD T score of - 1.0 or less. The sensitivity, specificity, predictive values, and accuracy of CAD for the identification of low skeletal BMD were calculated in dichotomous 2x2 tables. The likelihood ratio for a positive risk index result was also calculated.

Results: The sensitivity and specificity were 73.8% (95% confidence interval [CI], 63.1 to 84.5) and 68.6% (95% CI, 53.2 to 84.0), respectively, when BMD of the lumbar spine was used as standard. Those were 66.2% (95% CI, 54.9 to 77.4) and 56.7% (95% CI, 38.9 to 74.4), respectively, when BMD of the femoral neck was used as standard. The likelihood ratio was 2.35 (95% CI, 1.41 to 3.91) at the lumbar spine and 1.53 (95% CI, 0.98 to 2.38) at the femoral neck, respectively. Conclusion: Our results suggest CAD system applied for panoramic radiographs may be useful for the identification of women with low skeletal BMD.