Efficacy of Opportunistic Screening with Chest CT in Identifying Osteoporosis and Osteopenia in Patients with T2DM

Purpose: To explore the validity of the thoracic spine Hounsfield Unit (HU) measured by chest computed tomography (CT) for opportunistic screening of diabetic osteoporosis. The current study attempted to establish a diagnostic threshold for thoracic spine HU in a type 2 diabetes mellitus (T2DM) population with osteoporosis. Patients and Methods: The current study retrospectively included 334 patients with T2DM. They underwent chest CT and Dualenergy X-ray (DXA) between August 2021 and January 2022 in our hospital. HU values were measured on the resulting chest CT images at thoracic spine 11 and 12 to construct regions of interest. All patients were grouped according to the lowest T -value of DXA examination: osteoporosis, osteopenia and normal bone density. HU values were compared with T -values in each group of patients, and receiver operating characteristics curves were plotted to calculate diagnostic thresholds as well as sensitivity and specificity. Results: There was a strong correlation between the HU values of chest CT and the T -values of DXA (p < 0.01). The sensitivity for osteoporosis was 88.7% for T11 attenuation <= 98 HU and the specificity for osteoporosis was 87.5% for T12 attenuation <= 117HU; the specificity for normal BMD was 85.4% for T11 attenuation >= 147 HU and 82% for T12 attenuation >= 146 HU. Conclusion: Chest CT can be used to screen patients with T2DM for opportunistic osteoporosis and help determine if they need DXA screening. The current study suggests that when the HU threshold of T11 <= 98/T12 <= 117, patients may need further osteoporosis screening.