Investigation of mandibular bone changes in osteoporosis patients by computed tomography

MANDIBULAR CT ASSESSMENT IN OSTEOPOROSIS: RADIOMORPHOMETRIC AND HU-BASED INDICATORS The aim of this study was to evaluate the effectiveness of mandibular radiomorphometric indices (CTMI, CTI(S), CTI(I)) and Hounsfield Unit (HU) values measured via computed tomography (CT) in the diagnosis of osteoporosis. The research was conducted at the Department of Radiology, Faculty of Medicine, Fırat University, using CT images obtained during routine radiological examinations. The study group consisted of 50 patients over the age of 50 (regardless of sex) who were diagnosed with osteoporosis by the Department of Physical Medicine and Rehabilitation and whose bone mineral density (BMD) was assessed at the L1–L4 vertebral levels using dual-energy X-ray absorptiometry (DEXA), with a T-score ≤ -2.5 according to the criteria of the World Health Organization (WHO). The control group comprised 50 individuals with T-scores ≥ -1, considered healthy with respect to osteoporosis. The CTMI, CTI(S), and CTI(I) values obtained from the CT images were calculated as the averages of bilateral measurements. Additionally, bone density measurements from various regions of the mandible were recorded in Hounsfield Units (HU). The results revealed that mandibular radiomorphometric indices and HU values were significantly lower in osteoporotic individuals compared to healthy controls. These CT-based measurements demonstrated potential utility in detecting mandibular bone alterations associated with osteoporosis. Specifically, threshold values of CTMI ≤ 3.35 mm (sensitivity 86%, specificity 98%), CTI(I) ≤ 0.36 mm (sensitivity 78%, specificity 92%), and CTI(S) ≤ 0.27 mm (sensitivity 78%, specificity 98%) were identified as significant indicators of osteoporosis risk. HU thresholds of ≤ 337 for the angulus, ≤ 209 for the corpus, and ≤ 470 for the interdental region between teeth 3 and 4 may serve as preliminary diagnostic indicators. Among these, the angulus region demonstrated the highest diagnostic performance, with an area under the curve (AUC) of 0.857 and sensitivity of 90%, supporting its utility as a screening site. The inferior region of the first molar and the interdental area between teeth 3 and 4 also provided supportive diagnostic value. These findings