Estimating the Prevalence of Osteoporosis in Screening Eligible Women Based on the Thoracolumbar Hounsfield Unit (HU) Attenuation on Computed Tomography (CT)

Objective: The objective of this study was to determine the distribution of vertebral body trabecular attenuation on Computed Tomography (CT) in women who would be eligible for osteoporosis screening in order to create a framework to prioritize women for Dual Energy X-ray Absorptiometry (DXA) studies. Methodology: This retrospective study analyzed CT scans which included the T12 or L1 vertebral body performed between January 1, 2018 and July 31, 2023 in women between the ages of 65 - 75 who were members of our integrated healthcare system. For each CT scan, the mean attenuation of the trabecular bone of the L1 vertebral body was measured on three contiguous axial images centered at the mid-vertebral body. The T12 vertebral body was measured if the L1 vertebral body was not adequately visualized. The presence of vertebral body compression fractures was also noted. Results: The study comprised 1096 subjects with a mean (SD) age of 68.3 (3.2) years. Of these, 349 (31.8%) had a mean vertebral body HU value of 110 or less, and 478 (43.6%) had a mean vertebral body HU value of 120 or less. There was no statistical difference in the mean vertebral body HU between women of Asian/PI ethnicity and those who did not self-identify as being of Asian/PI ethnicity. Conclusion: We suggest that the opportunistic measurement of the CT attenuation of the L1 vertebral body can provide a framework to prioritize women 65 years or older for DXA studies and improve screening in at-risk populations. This method would lead to earlier diagnosis of osteoporosis, decreasing the negative impact on the individual, healthcare, and society.