MR扩散加权成像评估椎体骨量状况的初步研究

目的 探讨椎体MR扩散加权成像(DWI)测量值与双能X线(DXA)、定量GT(QCT)所测骨密度的相关性.方法 152例女性志愿者分别进行以下检查:胸腰椎侧位(T4～L4)X线平片,并采用Genant半定量法对其进行评阅;腰椎(L2～L4)DXA和QCT骨密度测量;腰椎常规行MR矢状面T2 WI、T1 WI和横断面T2 WI扫描;MR常规扫描结束后采用单次激发自旋回波平面回波扩散加权序列(SS-SE-EPI DWI)扩散敏感因子(b)=500 s/mm2]进行L2～L4椎体横断面DWI扫描,并使用GE-Functool分析软件测量相应椎体表观扩散系数(ADC值).计量资料间的相关性采用Pearson相关分析.结果 随年龄增加,椎体ADC值呈逐步降低趋势.L2～L4椎体平均ADC值(0.241×10-3 mm2/s)与相应椎体平均骨密度DXA(I.038 s/cm2)、QCT(104.2 mg/cm3)具有相关性(r值分别为0.461、0.731,P值均＜0.01).结论 DWI可在常规2腰椎MRI基础上无创性评估椎体骨髓变化状况,进而来评估骨髓的变化对于骨量状况所带来的影响.

MR diffusion weighted imaging in evaluating bone mineral density:a pilot study

Objective To investigate the correlation between vertebral diffusion weigllted imaging (DWI)and dual X-ray absorptiometry(DXA),quantitative computed tomography(QCT)for the evaluation of bone mineral density(BMD).Methods A total of 152 female volunteersaged from 30 to 80 years,mean age(58.2±14.2)years 1 were recruited in this study.All subjects underwent lateral thoracicolumbar radiographs,dual X-ray absorptiometry(DXA)and quantitative computed tomography(QCT),as well as DWI examination.Lateral spine radiographs(T4-L4)were evaluated with Genant's semiquantitative assessment.BMD was obtained by both DXA and QCT at lumbar spine(L2-L4).Axial vertebral(L2-4)DWI was performed with single shot spin-echo echo-planar imaging(SS-SE-EPI)sequenee (b value=500 s/mm2)after routine MRI examination(saginal T2 WI,T1 WI and axial T2 WI).Apparent diffusion coefficient(ADC)was measured with GE-Functool DWI software.Pearson correlation analysis was used for the statistics.Results There was a decreasing tendency in ADC value with age.A positive correlation was found between ADC(0.241×10-3 mm2/s)and BMD results measured by both DXA (1.038 S/cm3)and QCT(104.2 mg/cm3)examinations(r=0.461,0.731,respectively,P＜0.01).Conclusion DWI is an useful tool for noninvasive evaluation of the pathophysiologic changes of bone marrow in volunteers with difierent bone mineral density.