mDIXON-Quant技术评估中老年女性骨质量的临床研究

目的 探讨中老年女性腰椎骨髓脂肪分数（fat fraction, FF）和T2*值与骨密度（bone mineral density, BMD）的关联性及mDIXON-Quant技术对骨量下降的诊断效能。方法 招募中老年女性健康志愿者共126名，采用双能X线吸收测量仪（dual-energy X-ray absorptiometry, DXA）、定量CT（quantitative CT, QCT）测量腰椎椎体BMD，运用mDIXON-Quant技术测量腰椎FF和T2*值。分别根据DXA和QCT测量的BMD将受试者分为骨量正常组、骨量减少组、骨质疏松（OP）组。分析三组间FF、T2*值的差异并对FF、T2*值与BMD（DXA/QCT）进行相关分析，绘制受试者工作特征曲线(receiver operating characteristic curve, ROC)，分析FF、T2*值评估低骨量的诊断效能。结果 以DXA为标准分组：骨量正常组与骨质疏松组FF和T2*值、骨量减少组与OP组FF差异有统计学意义（P＜0.05），FF与BMD呈负相关（r= -0.365，P=0.000；校正年龄因素后r= -0.205，P=0.022），T2*值与BMD呈负相关（r= -0.221，P=0.013；校正年龄因素后r= -0.205，P=0.022），FF、T2*值、FF+T2*值评估低骨量的曲线下面积（area under curve, AUC）分别为0.625、0.631、0.657。以QCT为标准分组：骨量正常组与骨量减少组、与OP组FF及T2*值差异有统计学意义（P＜0.05），FF与BMD呈负相关（r= -0.687，P=0.000；校正年龄因素后r= -0.497，P=0.000），T2*值与BMD呈负相关（r= -0.360，P=0.000；校正年龄因素后r= -0.393，P=0.000），FF、T2*值、FF+T2*值评估低骨量的AUC分别为0.799、0.700、0.813。结论 mDIXON-Quant技术能够同时定量FF与T2*值，其评估以QCT为标准的低骨量的效能优于DXA，联合应用QCT与mDIXON-Quant技术能更准确评估中老年女性骨质量。

Clinical study of mDIXON-Quant technique in evaluating the bone quality of middle-aged and elderly women

Objective To investigate the correlations between fat fraction (FF) , T2* value and bone mineral density (BMD) and the diagnostic efficacy of mDIXON-Quant technique for bone mass loss in middle-aged and elderly women. Methods A total of 126 middle-aged and elderly female health volunteers were recruited, used dual-energy X-ray absorptiometry (DXA), quantitative CT (QCT) to measure the lumbar vertebral body BMD, used the mDIXON-Quant technique to measure the FF and T2* value of the lumbar spine. According to the BMD measured by DXA and QCT, the subjects were divided into the normal group, the osteopenia group, and the osteoporosis (OP) group. Analyzed the differences between FF and T2* value among the three groups and analyzed the correlations between FF, T2* value and BMD (DXA / QCT), drew the receiver operating characteristic curve (ROC), and analyzed the diagnostic efficacy of FF and T2* value to predict low bone mass. Results Group by DXA fas standard: the differences of FF and T2 * value between the normal group and the OP group, the difference of FF between the osteopenia group and the OP group were statistically significant (P<0.05),FF was negatively correlated with BMD (r = -0.365, P = 0.000; after adjusting for age factors, r = -0.205, P = 0.022), T2* value was negatively correlated with BMD (r = -0.221, P = 0.013; after adjusting for age factors, r = -0.205, P = 0.022), The area under curve (AUC) of FF, T2* value and FF + T2* value to predict low bone mass were 0.625, 0.631 and 0.657, respectively. Group by QCT as standard: the differences of FF and T2* value between the normal group and the osteopenia group, the differences of FF and T2* value between the normal group and OP group were statistically significant (P <0.05), FF was negatively correlated with BMD (r = -0.687, P = 0.000; after adjusting for age factor r = -0.497, P = 0.000), T2* value was negatively correlated with BMD (r = -0.360, P = 0.000; corrected age After factor r = -0.393, P = 0.000), the AUC of FF, T2* value and FF + T2* value to predict low bone mass were 0.799, 0.700 and 0.813 respectively. Conclusion The mDIXON-Quant technique can simultaneously quantify the FF and T2* value, and its'' performance in predicting low bone mass of QCT standard is better than that of DXA standard. The combined application of QCT and mDIXON-Quant technique can more accurately evaluate the bone quality of middle-aged and old women quality.