Sensitivity, Specificity, and Interrater Reliability in the use of Computed Tomography as an Alternative to Dual X-ray Absorptiometry to Detect Osteoporosis and Osteopenia

Osteoporosis and osteopenia are one of the significant public health problems due to related low bone mineral density (BMD) and increased risk of fracture.Dual X-Ray Absorptiometry (DXA) is considered the gold standard for BMD assessment but is limited in availability and cannot assess bone microachitecture.This study assessed the diagnostic performance of Computed Tomography (CT) against DXA based on sensitivity, specificity and interrater reliability.This prospective study was done over 12 months in a tertiary health care hospital in Chennai which included 128 adult patients who underwent routine CT Abdomen and Pelvis for unrelated conditions.CT-derived Hounsfield Unit (HU) measurements were compared with T-scores from DXA. Sensitivity, Specificity and interrater reliability (Intraclass Correlation Coefficient, ICC) were calculated.Statistical methods included Pearson correlation and linear regression analysis.CT had a sensitivity of 0.88 and specificity of 0.92 for identifying osteoporosis, while DXA had a sensitivity of 0.85 and specificity of 0.90 when compared to CT.For osteopenia, CT was also more sensitive (0.78) and specific (0.85) than DXA (0.75 and 0.80, respectively) The interrater reliability of radiologists interpreting CT scans was strong, with intraclass correlation coefficient (ICC) of 0.92 for osteoporosis and 0.85 for osteopenia.A significant positive correlation (r = 0.75, p < 0.05) was found between HU values and BMDCT provides a reliable alternative to DXA for pathologic identification of osteoporosis and osteopenia, with high sensitivity, specificity and reproducibility.Opportunistic supplementation of HU values during routine CT scans is easy to perform in practice, and provides a tool for detecting individuals at high risk for metabolic bone disease.