跟骨定量超声在筛查结缔组织病患者合并骨质疏松中的应用

Quantitative ultrasound scans of the calcaneus:a useful tool for screening osteoporosis in patients with connective tissue disease

目的：通过与双能X线（dual-energy X-ray absorptiometry,DXA）进行对比,确定跟骨定量超声（quantitative ultrasound,QUS）在结缔组织病患者骨质疏松诊断中的价值.方法：随机选取126名女性结缔组织病患者,采用DXA检测腰椎及右髋部骨密度,同时采用QUS扫描其右侧跟骨.结果：本组患者平均年龄（43.4±19.8）岁（30.0~80.0岁）.根据DXA结果,36例（28.6%）骨密度正常（T值≥-1.0）,90例（71.4%）骨密度异常,其中45例（35.7%）骨量减少（-2.5 〈T值〈-1．0），4-2例（33．3％）骨质疏松（T值≤-2．5），3例（2．4％）曾经发生过脆性骨折。在骨密度正常与异常者之间，QUS扫描结果BUA、SOS、SI、T值差异均有统计学意义。跟骨QUS扫描所得T值与腰椎及髋部DXA的T值正相关，相关系数分别为0．491和0．648（P〈0．01）。在校正了年龄和体重指数的影响后，跟骨QUS的T值与DXA的T值仍然呈正相关关系（腰椎：r=0．430，P=0．006；髋部：r=0．593，P〈0．001）。诊断腰椎和髋部骨质疏松的ROC曲线下面积分别为0．836（95％CI：0．695，0．977）和0．647（95％CI：0．579，0．957）。在跟骨QUS中选择T值-1．5作为界点时，诊断腰椎骨质疏松的灵敏度是70％，特异度为83．3％；选择T值-1．85作为界点时，诊断髋部骨质疏松的灵敏度是72．7％，特异度为88．9％。使用跟骨QUS的SI值诊断骨质疏松的最佳界点值为76（灵敏度为o．800，特异度为0．741）。结论：跟骨QUS扫描可以作为筛查女性结缔组织病患者中轴骨质疏松的辅助工具。

Objective：To evaluate the ability of calcaneus quantitative ultrasound （QUS） to diagnose osteoporosis in connective tissue disease （CTD） patients. Methods： In the study, 126 female patients with established CTD underwent dual-energy X-ray absorptiometry （DXA） of the lumber and right hip and QUS of the right heel at the same time. Sensitivity, specificity, as well as positive and negative pre- dictive values were calculated to determine the correlation between cases of osteoporosis detected by the QUS heel scan and by DXA. Results： The mean age of the 126 patients was （43.4 _＋ 19.8 ） years （ran- ging from 30.0 to 80.0 years）. Based on their DXA data, 36 （28.6%） patients had normal bone miner- al density （BMD, T score≥-1.0）, 90 （71.4%） patients had abnormal BMD. In abnormal BMD pa- tients, 45 （35.7%） had osteopenia （ -2.5 〈 T score 〈 -1.0）, and 42 （33.3%） were osteoporotic （T score≤ -2.5 ）, while 3 （2.4%） patients had fragile fracture. Broadband ultrasound attenuation （ BUA）, speed of sound （SOS） and stiffness index （SI） were all significantly different between osteope- nia and the normal group when scanning with QUS. QUS T score was positively correlated with DXA T score, both at lumber and right hip respectively （ r = 0. 491, 0. 648, P 〈 0.01 ）. After correction by age and BMI, QUS T score remained positively correlated with DXA T score by partial correlation analysis （ Pearson partial vertebral r = 0. 430, P = 0. 006 ; right hip r = 0. 593, P 〈 0.001 ）. The area under the ROC curve for diagnosis of lumber and hip osteoporosis were 0. 836 （95 % CI： O. 695, 0.977 ） and 0. 647 （95% CI： O. 579, 0.957） separately. The sensitivity and specificity for identifying osteoporosis in lum- ber were 70% and 83.3% respectively when the T score threshold of QUS was defined as - 1.5 ; howev- er, the sensitivity and the specificity for identifying osteoporosis at right hip were 72.7% and 88.9%