The Study Of The Difference Of Bilateral Proximal Femur Bone Mineral Density In DXA Measurements

[Objective]Based on the process of dual-energy X-ray absorptiometry (DXA) densitometry measurement quality control, to investigate the differences of the bone mineral density (BMD) at the bilateral proximal femur and determine the diagnostic value of bilateral femoral BMD measurements in postmenopausal females. [Methods]Measured the lumbar vertebra phantom supplied by factory daily, and compared the results with real value, then calculated the accuracy. 30 subjects were chosen, each subject was scanned twice, the precision and the least significant change (LSC) of each examinated regions were calculated. Dual femur (femoral neck, upper neck, trochanter and total hip) measurements using GE Lunar Prodigy were performed in 817 women and 284 men in Guangzhou district. 504 postmenopausal women were diagnosed based on the lowest T-score of bilateral measurement sites, using the diagnostic classification established by the World Health Organization. [Results]The accuracy of DXA densitometer was -0.81%, Measurement precision (RMS-CV%) with single femur was 0.7-2.2%; dual femur precision was 0.6-1.2%, depending on the site. The dual femur mean BMD (average of L/R) provides an additional 20-45% improvement in precision compared to a single femur measurement. Strong correlations (r = 0.86-0.97, P<0.01) were found between left and right femur BMD values in each group. No significant differences between bilateral femoral BMD were observed in total, male and postmenopausal women groups (P>0.05). There was significant but small...