腰椎定量CT与双能X线骨密度测量对老年患者骨质疏松检出率的比较分析

Comparison of osteoporosis detected by DXA and QCT in elderly population

目的评估腰椎定量CT骨密度测定(QCT)与双能X线骨密度测量(DXA)在老年骨质疏松症的检出中是否存在差异,并分析其可能的影响因素。方法对短期内行腰椎正位DXA和腰椎QCT2项检查的108例老年人骨质疏松的检出率进行比较,通过腰椎CT对腰椎退行性变和腹主动脉钙化进行半定量分析。结果腰椎正位DXA对骨质疏松的检出率为17.6%,腰椎QCT为44.4%,检出率差异有统计学意义(P<0.01)。单因素与多因素分析结果表明,重度椎体骨赘形成可造成腰椎正位DXA对骨质疏松的检出率低于腰椎QCT,而年龄、小关节增生、棘突骨质增生、终板硬化、椎体变形及腹主动脉钙化对骨质疏松的检出率无显著影响。结论腰椎QCT测量骨密度在老年患者骨质疏松的诊断中可能具有较高的临床价值。

Objective To investigate the difference and reason of spinal bone mineral density （BMD） measured by quantitative CT （QCT） and dual X-ray absorptiometry （DXA） in assessing the osteoporosis in a group of relative old population. Methods Spinal BMD was measured by both QCT and posterior-anterior DXA （PA-DXA） in 108 subjects in two months. The detecting rate of osteoporosis by two methods was calculated and the difference was assessed. The lumbar CT images of 108 subjects were reviewed using semi quantitative method for evaluation of spinal degeneration and abdominal aortic calcification （AAC）. Results The detecting rate of DXA was 17.6% , while QCT picked up 44.4%. The detecting rate of osteoporosis was different significantly between DXA and QCT （P 〈0. 01 ）. Single and multiple factor analysis indicated that the difference between the detecting rate of DXA and QCT was significantly higher in subjects with serious vertebral osteophytes than those without or with mild vertebral osteophytes. And it was seldom correlated with age, facet joint osteoarthritis, spinous process osteophytes, end plate sclerosis, vertebral body compres,sion and AAC. Conclusion QCT is superior to PA-DXA in detecting osteoporosis in elderly patients.