Opportunistic screening for osteoporosis on routine computed tomography? An external validation study.

Area of Science:

• Radiology
• Osteoporosis Diagnosis
• Medical Imaging

Background:

• Osteoporosis screening can be opportunistic using computed tomography (CT) scans that visualize the spine.
• Vertebral Hounsfield unit (HU) measurements offer a potential method for identifying patients with osteoporosis.

Purpose of the Study:

• To verify the diagnostic performance of vertebral HU measurements on routine CT scans for diagnosing osteoporosis.
• To assess this diagnostic capability in a separate, external patient population.

Main Methods:

• Retrospective inclusion of patients who underwent CT (chest or abdomen) and dual-energy X-ray absorptiometry (DXA).
• Evaluation of CTs for vertebral fractures and measurement of vertebral attenuation (density) values.
• Calculation of diagnostic performance measures and area under the receiver operator characteristics curve (AUC).

Main Results:

• Included 302 patients (mean age 57.9 years); 27% had osteoporosis by DXA, 22% had vertebral fractures.
• Vertebral HU measurements demonstrated modest diagnostic performance with a maximal AUC of 0.74.
• Optimal threshold sensitivity was 62% and specificity was 79%.

Conclusions:

• Routine CT vertebral density measurements contain diagnostic information for bone mineral density, validating previous findings.
• Diagnostic accuracy was substantially lower than previously reported in external validation.
• Findings may inform the implementation of opportunistic osteoporosis screening strategies.