磁共振扩散加权成像表观扩散系数、信号强度比对腰椎骨质疏松的定量评价

目的:探讨磁共振扩散加权成像(diffusion weighted imaging,DWI)表观扩散系数(apparent diffusion coefficient,ADC),信号强度比(signal intensity ratio,SIR)在腰椎骨质疏松定量评价中的应用价值。方法:选取2017年5月至2019年10月接受双能X线吸收(dualenergy X ray absorption,DXA)骨密度(bone mineral density,BMD),腰椎常规MRI扫描和DWI扫描检查的腰椎疾病患者175例。根据DXA骨密度T值分为骨质疏松组(64例)、骨量减少组(53例)、骨量正常组(58例)。测量比较3组腰椎L_2-L_4的ADC、SIR值;分析ADC、SIR值与BMD的相关性;采用受试者工作特征(receiver operator characteristic,ROC)曲线分析ADC,SIR值对腰椎骨质疏松与骨量减少,腰椎骨质疏松与骨量正常及腰椎骨质疏松的鉴别诊断价值。结果:3组ADC、SIR值比较差异均有统计学意义(F=41.386、37.114,均P=0.000);骨质疏松组ADC值低于骨量减少组、骨量正常组(t=3.540、9.069,P=0.001、0.000);骨质疏松组SIR值高于骨量减少组、骨量正常组(t=5.083、8.523,均P=0.000)。Spearman相关性分析显示:ADC值与BMD呈正相关(r=0.313,P=0.004);SIR值与BMD呈负相关(r=-0.589,P=0.000)。ROC曲线分析显示:ADC、SIR诊断腰椎骨质疏松骨量减少的曲线下面积(area under curve,AUC),敏感度,特异度分别为0.742,89.1%,52.8%和0.729,89.1%,50.9%(均P=0.000);ADC、SIR诊断腰椎骨质疏松骨量正常的AUC,敏感度,特异度分别为0.815,100.0%,50.0%和0.856,65.6%,93.1%(均P=0.000);ADC、SIR诊断腰椎骨质疏松的AUC,敏感度,特异度分别为0.78,89.1%,51.4%和0.795,50.0%,94.6%(均P=0.000);均有一定诊断价值。结论:ADC、SIR能够较好地反映腰椎疾病患者BMD情况,可对骨质疏松的椎体进行定量评价,二者水平对腰椎骨质疏松具有重要的辅助诊断作用。

Quantitative evaluation of lumbar spine osteoporosis by apparent diffusion coefficient and signal intensity ratio of magnetic resonance diffusion-weighted magnetic resonance imaging

Objective: To investigate the application value of apparent diffusion coefficient (ADC) and signal intensity ratio (SIR) of MR diffusion-weighted imaging (DWI) in quantitative evaluation of lumbar spine osteoporosis.Methods: A total of 175 patients with lumbar spine diseases who received dualenergy X-ray absorption (DXA) bone mineral density (BMD),routine MRI and DWI of the lumbar spine from May 2017 to October 2019 were selected. According to the T-value of DXA,the patients were divided into osteoporosis group (64 cases),osteopenia group (53 cases) and normal bone mass group (58 cases). The ADC and SIR values of L₂-L₄ were measured and compared among the three groups and the correlation between ADC,SIR and BMD was analyzed. The ROC curve was used to evaluate the differential diagnosis value of ADC and SIR for osteoporosis,osteopenia and normal bone mass.Results: There were statistically significant differences in ADC and SIR values among three groups(F=41.386,37.114,all P=0.000). The ADC value of the osteoporosis group was lower than that of the osteopenia group and the normal bone mass group,and the difference was statistically significant (t=3.540,9.069,P=0.001,0.000);the SIR value of the osteoporosis group was higher than that of the osteopenia group and the normal bone mass group,and the difference was statistically significant(t=5.083,8.523,all P=0.000). Spearman correlation analysis showed that ADC value was positively correlated with BMD (r=0.313,P=0.004);SIR value was negatively correlated with BMD (r=-0.589,P=0.000). Receiver operator characteristic (ROC) curve analysis showed that the area under curve (AUC),sensitivity and specificity of ADC and SIR in the diagnosis of lumbar osteoporosis and osteopenia were 0.742,89.1%,52.8% and 0.729,89.1%,50.9% respectively (P=0.000);the AUC,sensitivity and specificity of ADC and SIR in the diagnosis of lumbar osteoporosis and normal bone mass were 0.815,100.0%,50.0% and 0.856,65.6%,93.1%,respectively (P=0.000);the AUC,sensitivity and specificity of ADC and SIR in the diagnosis of lumbar osteoporosis were 0.78,89.1%,51.4% and 0.795,50.0% and 94.6% respectively (P=0.000);All have a certain diagnostic value.Conclusion: ADC and SIR can better reflect the BMD of patients with lumbar diseases,and can quantitatively evaluate the vertebral body of osteoporosis,which play an important role in the diagnosis of lumbar osteoporosis.