Objective
The purpose of the present study is to compare the bone mineral density (BMD) evaluated by dual energy
x-ray absorptiometry(DXA) and quantitative computed tomography (QCT).
Methods
From December 2008 to April 2009, 32 patients with hip fracture or hip disease were enrolled in our study.
BMD of the contralateral, normal side of the proximal femur was measured by DXA and QCT. The differences of
BMD in the femoral neck, trochanter, total proximal femur and ward area in the two methods were analyzed using the
Wilcoxon signed rank test. The relationship of each BMD in the two methods was evaluated using the Spearman
correlation coefficient.
Results
BMD of the femoral neck was 0.644 ± 0.132 g/cm2 by DXA and 0.516 ± 0.116 g/cm2 by QCT. Trochanter
BMD was 0.526 ± 0.141 g/cm2 by DXA and 0.407 ± 0.125 g/cm2 by QCT. Total proximal femur BMD was measured
as 0.660 ± 0.139 g/cm2 and 0.547 ± 0.129 g/cm2, while the BMD in the Ward area was 0.437 ± 0.131 g/cm2 and
0.299 ± 0.167g/cm2. respectively according to DXA and QCT. The Wilcoxon signed rank test confirmed the differences
of BMD between DXA and QCT in all areas (P < 0.001). The Spearman correlation coefficient was 0.699, 0.967, 0.951,
and 0.460, respectively, at the femoral neck, trochanter, total proximal femur, and Ward area, and these correlations
were statistically significant (P < 0.001).
Conclusion
The average BMD measured by QCT was lower than that by DXA. The BMD in the two methods showed
positive correlation. Therefore we conclude that BMD using QCT measured lower than BMD using DXA.
[Korean Journal of Bone Metabolism, 16(2): 71-77, 2009]
