Quantitative calcium-based assessment of osteoporosis in dual-layer spectral CT

•Virtual calcium-only images (VCa) show good correlation with DEXA bone mineral density.•VCa might be used to estimate BMD as it is less prone to bone marrow changes.•A VCa cut-off of 126 HU can be used to identify abnormal bone mineral density. To evaluate a novel calcium-only imaging technique (VCa) with subtracted bone marrow in osteoporosis in dual-layer CT (DLCT) compared to conventional CT images (CI) and dual-energy X-ray absorptiometry (DXA). Images of a multi-energy CT phantom with calcium inserts, quantitative CT calibration phantom, and of 55 patients (mean age: 64.6 ± 11.5 years) were acquired on a DLCT to evaluate bone mineral density (BMD). CI, calcium-suppressed images, and VCa were calculated. For investigating the association of VCa and CI with DXA a subsample of 30 patients (