Accuracy, agreement, and reliability of DECT-derived vBMD measurements: an initial ex vivo study

Objectives To assess the agreement and reliability of DECT (dual-energy CT)-derived vBMD (volumetric bone mineral density) measurements from excised human femoral heads and to compare DECT-derived BMD with that measured by DXA (dual-energy X-ray absorptiometry) and QCT (quantitative CT) to determine its accuracy. Methods Twenty patients that underwent total hip arthroplasty were enrolled to this study. Femoral heads were excised to rectangles without cortical bones for scanning. A dual-source DECT scanner generated images under 80/Sn140 kVp and 100/Sn140 kVp scanning conditions. Specimens were subsequently scanned by QCT and DXA to produce QCT-derived vBMD (mg/cm(3)) and DXA-derived BMM (bone mineral mass, g). DECT images were loaded to a post-processing workstation to calculate DECT-derived vBMD and BMM. Results Higher DECT-derived vBMD and BMM were found under 80/Sn140 and 100/Sn140 kVp compared with those for QCT and DXA (p = 0.005). DECT-derived vBMD was highly correlated with QCT-derived vBMD (r = 0.961 similar to 0.993,p < 0.05). Similarly, DECT-derived BMM was strongly correlated with DXA-derived BMM (r = 0.927 similar to 0.943,p < 0.05). Agreement of the inter- and intra-observation of DECT-derived vBMD was excellent. Linear regression was carried out to calibrate DECT-derived vBMD of 80/Sn140 kVp (14 + 0.7 x DECT-derived vBMD) and 100/Sn140 kVp (74 + 0.4 x DECT-derived vBMD) with the reference of QCT-derived vBMD. After calibration, excellent agreement was found for vBMD and BMM within various imaging modalities. Conclusions Our study showed that DECT-derived vBMD exhibited high agreement and reliability features, and after calibration, it also displayed a high degree of accuracy. However, in vivo studies are needed to extend its potential utility in clinical settings.