Opportunistic screening of hip osteoporosis using Phantom-Less quantitative CT-Derived thoracic volumetric BMD from routine chest CT: A Multicentre, retrospective study

To develop and validate diagnostic thresholds for thoracic volumetric bone mineral density (vBMD) derived from routine chest CT scans, and to evaluate the performance of this metric for opportunistic screening of hip osteoporosis (hOP) and hip osteopenia in adults aged 60 years and older.

This multicenter retrospective study enrolled 568 patients aged 60 years and older who underwent both non-contrast chest computed tomography (CT) and dual-energy X-ray absorptiometry (DXA). Thoracic quantitative CT-derived volumetric bone mineral density (Th-vBMD) was measured using a phantomless quantitative CT (PL-QCT) system. The robustness of the diagnostic model was evaluated through internal validation, including 500-iteration bootstrap resampling. The diagnostic performance of Th-vBMD was compared against the reference hip DXA T-score.

A total of 568 patients were included. The prevalence of hOP and hip osteopenia was 36.3 % and 42.6 %, respectively. Th-vBMD demonstrated performance with an area under the curve (AUC) of 0.873 (95 % CI: 0.837-0.910). The optimal Th-vBMD threshold for hOP was 85.4 mg/cm³, sensitivity 0.851 and specificity 0.864. The optimal threshold for hip osteopenia was 120.7 mg/cm³, sensitivity: 0.860 and specificity: 0.811. Logistic regression identified Th-vBMD ≤ 85.4 mg/cm³ as an independent predictor of hOP (adjusted OR: 26.70; 95 % CI: 16.3-45.0; p < 0.001).

This study establishes and validates Th-vBMD thresholds derived from routine chest CT for opportunistic hOP screening in elderly. This cost-effective strategy leverages clinical imaging data to identify individuals at osteoporosis risk, facilitating intervention and advancing osteoporosis prevention.