Automated measurement of mandibular cortical width on dental panoramic radiographs

Abstract

Mandibular cortical width (MCW) measured on dental panoramic radiographs (DPRs) was significantly correlated with bone mineral density. We developed a computer-aided diagnosis scheme that automatically measures MCW to assist dentists in describing a possible osteoporotic risk and suggesting further examinations. In our approach, potential mandible edges are detected by modified Canny edge detector. On the basis of the edge information, a contour model is selected from the reference data and is fitted to the test case by using the active contour model. The reference mental foramina positions of the model are employed as the MCW measurement locations. The MCW is measured on the basis of the grayscale profiles obtained along the lines perpendicular to the fitted mandible contour. One hundred DPRs, including 26 DPRs from osteoporotic cases, were used to evaluate our proposed scheme. Experimental results showed that the average MCWs for osteoporotic and control cases were 2.2 and 3.9 mm, respectively. When a threshold of 2.7 mm was applied, the sensitivity and specificity for identifying osteoporotic patients were 88.5 and 97.3 %, respectively. An automated MCW measurement technique is feasible using DPRs, and this method has a potential to identify asymptomatic osteoporotic patients.