老年女性骨质疏松三维骨容积和定量CT骨密度比较

Comparison of bone mineral density between volumetric quantitative CT and quantitative CT for the elderly women with osteoporosis

目的采用多层螺旋CT的容积扫描和定量CT（QCT）测量老年女性骨密度,以评估容积定量CT（vQCT）技术在诊断骨质疏松性骨折中的价值。方法42例52～84岁女性,平均（67.8±9.5）岁,分为3组：骨质疏松骨折组、骨质疏松无骨折组、健康对照组,每组14例。骨折的确定方法为非外力或非严重外力下发生的椎体或股骨颈骨折,根据X线摄片诊断确定;骨质疏松的诊断采用双能X线骨密度测量仪确定。每例均采用了第3腰椎椎体的vQCT和1～3腰椎QCT扫描。三维图像的处理和分析采用了CT机的容积测量分析软件。结果3组的vQCT参数两两比较,差异有统计学意义（F=16.45,P〈0.01）;3组松质骨QCT比较,骨质疏松骨折组、骨质疏松无骨折组与健康对照组比较,差异有统计学意义（F=13.27,P〈0.01）;皮质骨QCT骨质疏松骨折组与健康对照组比较,差异有统计学意义（F=4.27,P=0.015）。组内相关性比较,骨质疏松骨折组的vQCT参数与QCT的皮质骨呈正相关（r=0.7813,P〈0.01）。结论vQCT和QCT是2种同样采用CT的检测方法,vQCT测量采集数据的范围大于QCT,且测量和计算着重于骨的容积.因此,vQCT是一种对骨质疏松骨性折预测可靠、有效的检查方法。

Objective To determine the effect of vertebral fracture status on trabecular and cortical bone mineral density measurements obtained in spine by volumetric and non-volumetric quantitative computed tomography （QCT）. Methods Fouty-two Chinese women [average age （67. 7±6.9） years] were subdivided into 3 groups： a fractured osteoporotic group （n= 14） with radiographically confirmed atraumatic vertebral fractures, a non-fractured osteoporotic group （n= 14） and a healthy group （n= 14）. Diagnosis of osteoporosis was confirmed by dual X-ray absorptiometry （DXA）. The subjects received spiral CT scans of L3 vertebral bodies （Siemens AG, Germany）. To compare the vQCT results, the quantitative CT scans of L1-3 were also obtained. The three dimensional CT images were processed and analyzed using volumetric analysis software （Siemens AG, Germany）. Results The vQCT and trabecular and cortical QCT in the osteoporotic fractured subjects, the osteoporotic non-fractured subjects and the age-matched healthy controls were computed and analyzed. The results showed statistical differences among the three groups of vQCT （P〈0. 01）. And trabecular QCT demonstrated statistical differences only between the osteoporotic fractured subjects and the age-matched healthy controls, and the osteoporotic subjects without fractures and the age-matched healthy controls （F = 13.27, P〈 0. 01）. The cortical QCT comparison among 3 groups, only fractured and healthy control groups showed less significant differences （F= 4.27,P = 0.015）. In the fractured group, vQCT was also associated with cortical QCT （r = 0. 7813, P 〈 0.01） . Conclusions The vQCT and QCT techniques are equivalent in modality used, however, vQCT is effective and could be used more reliably in patients with vertebral fractures for predicting osteoporotic fractures since a bigger volume of data is covered and calculated.