QCT与DXA对绝经后妇女骨质疏松症检出率的对比

目的 对比定量计算机断层扫描法（quantitative computed tomography,QCT）与双能X线吸收法（dual energy X-ray absorptiometry,DXA）在绝经后妇女中骨质疏松症的检出率，并分析两者差异性的原因。方法 收集的148例绝经后妇女，平均年龄（63.7±10.4）岁，分别采用DXA、QCT测量腰椎骨密度（bone mineral density,BMD），计算2种方法对骨质疏松症的检出率，并对测量的结果进行分析比较，查看诊断不一致患者的腰椎CT平扫图像，以评估是否有椎体骨折、脊柱退行性改变和腹主动脉钙化等情况。结果 148例受试者，QCT的检出率为45.9%(68/148),DXA的检出率为26.4%(39/148)，差异有统计学意义（P <0.05）。92例受试者（62.2%）的DXA和QCT的诊断是一致的；56例（37.8%）受试者DXA和QCT的诊断不一致，其中QCT诊断为骨质疏松，DXA为骨量减少的例数占48.2%(27/56);QCT为骨量减少，DXA为骨量正常的例数占33.9%(19/56)。在56例诊断不一致的患...

A Comparative Study of QCT and DXA on Detection of Osteoporosis in Postmenopausal Women

  Objective  To compare the detection rate of osteoporosis in postmenopausal women with quantitative computed tomography （QCT） and dual energy X-ray absorptiometry （DXA）, and analyze the causes for differences.   Methods   A total of 148 postmenopausal women were enrolled, with an average age of （63.7±10.4） years old. The lumbar spine bone mineral density was measured by DXA and QCT, respectively. The detection rate of osteoporosis by the two methods was calculated, and the measurement results were analyzed and compared. The plain CT images of patients with inconsistent diagnosis were checked to evaluate whether there were vertebral fracture, degenerative changes of spine and aorta abdominalis calcification.  Results   In 148 subjects, the detection rate of QCT was 45.9% （68/148）, and the detection rate of DXA was 26.4% （39/148）, the difference was statistically significant （P < 0.05）. The diagnosis of DXA and QCT was consistent in 92 subjects （62.2%）; the diagnosis of DXA and QCT was inconsistent in 56 subjects （37.8%）. 48.2% of the patients （27/56） were diagnosed as osteoporosis by QCT and bone mass reduction by DXA. 33.9% （19/56） of patients were diagnosed as bone mass reduction by QCT and normal bone mass by DXA. Of all patients with inconsistent diagnosis, 2 （2/56） had vertebral compression fractures, and 56 （56/56） had lumbar degeneration （osteophytes, endplate sclerosis, ligament ossification or facet joint osteoarthritis）, 9 （9/56） had abdominal aortic calcification.  Conclusion  The inconsistent detection rates of osteoporosis between QCT and DXA may be caused by the presence of spinal degeneration, abdominal aortic calcification and other sclerotic lesions, which will increase the BMD value of DXA, resulting in the higher detection rate of QCT than DXA. Compared with DXA, QCT is a more sensitive method for the diagnosis of osteoporosis in postmenopausal women.