Cross Calibration of Two Dual-energy X-ray Densitometers for the Measurement of Bone Mineral Density in Young Adults

SMSU Event Center BC

The assessment of bone mineral density (BMD) is essential to skeletal health, and Dual-energy X-ray absorptiometry (DXA) is a type of bone densitometer that is widely used in both clinical and research settings. When changing a DXA system during longitudinal monitoring, it is important to conduct cross-calibration between the new scanner and the reference scanner to ensure that BMD values measured by the two systems are as close as possible (International Society for Clinical Densitometry Position Stand, 2015). Purpose: To properly cross calibrate between the GE iDXA and Prodigy in healthy young adults. Methods: Ten healthy college age individuals, including four males (24.2 ± 2.1 years; 170.2 ± 6.1 cm; 84.9 ± 11.3 kg) and six females (22.1 ± 1.3 years; 157.4 ± 3.1 cm; 60.9 ± 15.5 kg) participated in the study. The BMD at lumbar spine and dual femur were measured using the GE iDXA and Prodigy by the same licensed technician on the same day. Paired-T test and regression analysis were performed to compare the BMD values between the two systems. Results: There were no significant differences in BMD of left total femur and left femoral neck between the two systems. However, statistically significant differences of BMD at AP spine L1-L4 (p = 0.002), right total femur (p = 0.027) and right femoral neck (p = 0.038) were identified between the two systems. Conclusion: Our results suggest that calibration equations are needed when comparing the BMD at lumbar spine and right hip between the iDXA and Prodigy.