Opportunistic osteoporosis assessment from routine CT—effect of intravenous contrast agents on absolute values, T-scores, and derived classifications in single- and dual-energy CT
摘要
Computed tomography (CT) is widely used for bone health assessment, impacting osteoporosis diagnosis and treatment. However, the influence of intravenous contrast agents on CT-based bone mineral density (BMD) measurements remains debated. This study evaluates the effect of contrast agents on Hounsfield measurements, T-scores, and Z-scores, assessing their impact on diagnostic accuracy to reduce misclassification and optimize CT-based BMD assessment.
Materials and methodsA retrospective analysis of 597 patients (median age: 66 years, 157 females, 440 males) was performed using dual-energy CT (DECT) scans of the abdomen and chest. All patients underwent non-contrast, arterial, and venous phase CT. Automated segmentation (nnU-Net) delineated L1 and L1–L4 trabecular bone, validated by two radiologists. T-scores were calculated according to DEXA-equivalent guidelines.
ResultsBased on non-contrast CT, 35% were diagnosed with osteoporosis, 46% with osteopenia, and 18% had normal bone status. Median T-score was −2.0 (L1) and −2.1 (L1–L4) (p < 0.001). Contrast agents significantly altered BMD values, with median changes of 22.9% (arterial) and 20.1% (venous). The most pronounced changes occurred in patients under 50 years (+99% at L1, p < 0.001). In older females, 21% were misclassified as osteopenic instead of osteoporotic (p < 0.001).
ConclusionsContrast agents significantly affect BMD measurements, leading to diagnostic misclassification. This effect should be considered when using CT for osteoporosis diagnosis and treatment planning.
Key Points