Leveraging Thoracic CT for Opportunistic Osteoporosis Screening

Routine thoracic CT scans offer an opportunity for opportunistic osteoporosis screening by assessing thoracic CT attenuation. This identifies low vertebral bone density on images obtained for other indications and enables earlier detection without dedicated scans, providing actionable findings within existing workflows and radiology reports.

Thoracic CT attenuation correlates strongly with bone mineral density measured by dual-energy X-ray absorptiometry (DXA), which remains the diagnostic standard guiding treatment. CT attenuation delivers image-derived density estimates that align with BMD thresholds and serves principally as a complementary risk-identification tool rather than a replacement for DXA.

In a retrospective cohort of 318 patients — including a 50-patient validation subset with paired chest CT and DXA — the primary endpoint was prediction of osteoporosis or low BMD. ROC analysis showed high discriminative performance, with reported sensitivity 90.7% and specificity 90.1% for the study’s thoracic CT metrics.

Reproducibility improved when measurements used standardized ROI placement on T10–T12 vertebral bodies, consistent Hounsfield-unit calibration (including phantom or calibration-bias checks), and automated segmentation or AI-assisted measurement alongside inter-reader agreement reporting.

Recommended operational steps include protocol templates, routine QA checks, and clear reporting language that specifies attenuation thresholds and uncertainty to support consistent measurement across scanners and readers.

Next steps for programs include piloting local workflows, validating attenuation thresholds within their populations, and integrating automated measurements into reporting pipelines. These pilots refine thresholds and QA processes while keeping patient burden low and increasing opportunities for earlier fracture-risk detection.