Quantitative Computertomographie der Knochenmineraldichte des Unterkiefers Darstellung der topographischen Verteilung der Knochenmineraldichte bei automatisierter Segmentierung der Kieferstrukturen

PURPOSE: Confirmation of a new technique for evaluating bone mineral density (BMD). Colored coded imaging of topographical distribution of bone mineral density in the spongy substance. METHOD: For 20 patients, dental CT examinations of the mandible were made in axial slices. Spongy substance and cortical bone pixels were automatically segmented at foramina mentalia level by means of threshold fixation. The segments were separated in areas relevant to implantology. For each region, BMD was measured by means of quantitative computed tomography (QCT). Spongiose substance of 20 mandibles was segmented by using three threshold intervals to image topographical BMD distribution. RESULTS: Cortical bone and spongy substance could be automatically segmented for 20 mandibles. BMD could be measured in each region. The results were comparable with those of other techniques. Three threshold intervals were segmented for 20 mandibles in the spongy substance to depict topographical BMD distribution. CONCLUSIONS: Areas of low BMD can be detected by imaging topographical BMD distribution. This way, subjective rating by the examiner is eliminated.