The Comparative Study between Bone Mineral Density Measured by Dual Energy X-ray Absorptiometry and Quantitative Computed Tomography

Objective To compare the relationship of values measured by two different bone density measure methods (QCT and DXA) with bone ash density, and evaluate the clinic value of QCT in bone density. Materials and Methods 15 pig lumbar vertebral bodies were recruited. After removal of surrounding parenchyma and adjunct, BMD was measured by both QCT and DXA. The adjunct-removed vertebrae were incinerated. The gross value of BMC and BMD respectively measured by QCT and DXA were compared with the bone ash weight and bone ash density of incinerated vertebrae. After calculated the volume BMD measured by DXA, we further calculated the skewness of cortical BMD、trabetical BMD measured by QCT and the volume BMD measured by DXA compared with bone ash density. Results The correlation of trabetical BMD、cortical BMD measured by QCT and bone ash weight、bone ash density were at a high level of significance (P0.005), and the correlation of BMC measured by DXA and the bone ash weight was the highest(r=0.9995)。The skewness of trabetical BMD (Average is 0.1489) was lower than the skewness of the volume BMD measured by DXA (Average is 0.2708). Conclusion Two bone density measure methods (QCT and DXA) are both good methods to measure BMD and diagnose osteoporosis。The trabetical BMD measured by QCT is more close to bone ash density( true BMD). Changes of bone metabolism in osteoporosis can be better and more accurately reflected BMD measured by QCT than that by DXA.