IVIM-DWI对早期活动性AS骶髂关节炎的诊断价值

Diagnostic value of intravoxel incoherent motion diffusion-weighted imaging for early active ankylosing spondylitis

[目的]探讨基于体素内不相干运动(IVIM)模型的磁共振扩散加权成像(IVIM-DWI)序列在早期活动性强直性脊柱炎(AS)中的诊断价值。[方法]收集2017年1月～2017年12月诊断的42例早期活动性强直性脊柱炎患者和40例健康志愿者的临床及影像资料。根据MRI常规序列上是否有明确骨髓水肿将活动期AS患者分为阳性组(32例)和阴性组(10例),将健康志愿者作为对照组(40例)。测量三组IVIM-DWI相关参数D_(slow)、D_(fast)、f。采用独立样本t检验分析各组IVIM-DWI参数的统计学差异,绘制ROC曲线,分析各参数对阳性组与对照组、阴性组与对照组的诊断效能。[结果] D_(slow)、D_(fast)及f的平均值分别为阳性组[(0.75±0.07)×10^(-3)mm^2/s,(10.76±0.86)×10^(-3)mm^2/s,(0.47±0.08)]、阴性组[(0.34±0.05)×10^(-3)mm^2/s,(13.02±1.50)×10^(-3)mm^2/s,(0.45±0.04)]、对照组[(0.34±0.04)×10^(-3)mm^2/s,(10.51±1.24)×10^(-3)mm^2/s,(0.38±0.03)]。阳性组的D_(slow)和f值显著高于对照组,差异有统计学意义(P<0.05),而阴性组的D_(fast)和f值显著高于对照组,差异有统计学意义(P<0.05)。根据ROC曲线分析得出,鉴别阳性组与对照组的最佳临界值为D_(slow)=0.51×10^(-3)mm^2/s (1.00、100%、100%)。鉴别阴性组与对照组的最佳临界值(ROC曲线下面积、敏感度及特异度)分别为D_(fast)=11.86×10^(-3)mm^2/s (0.91、90.0%、80.0%)及f=0.41(0.95、90.0%、85.0%)。[结论]当早期活动性AS患者常规序列出现明确骨髓水肿时,D_(slow)的鉴别诊断价值较高。而常规序列无明确骨髓水肿时,D_(fast)及f值的鉴别诊断价值较高。

[Objective] To assess the diagnostic value of intravoxel incoherent motion(IVIM) diffusion-weighted imaging(DWI) for the active ankylosing spondylitis(AS) in early stage. [Methods] From January 2017 to December 2017, 42 patients with early active ankylosing spondylitis and 40 healthy volunteers were included into this study. According to whether or not a definitive bone marrow edema was noted in the images of routine MRI sequences, the patients were divided into the positive group(n=32) and negative group(n=10), additionally, the healthy volunteers were used as control group(n=40). The IVIMDWI related parameters, such as Dslow, Dfast andf, were measured in the three groups. The independent sample t test was used to analyze the statistical differences of IVIM-DWI parameters among groups, and the ROC curve was drawn to analyze the diagnostic efficacy of each parameter in the positive group and control group, the negative group and control group. [Results] The mean values of Dslow, Dfast and f were [(0.75±0.07)×10^-3mm^2/s,(10.76±0.86)×10^-3mm^2/s and(0.47±0.08)] in the positive group,[(0.34±0.05) ×10^-3mm^2/s,(13.02±1.50)×10^-3mm^2/s and(0.45±0.04) ] in the negative group, whereas [(0.34±0.04) ×10^-3mm^2/s,(10.51±1.24) ×10^-3mm^2/s and(0.38± 0.03)] in the control group. The positive group had statistically higher Dslow and f than the control group(P<0.05), while the negative group had statistically higher Dfast and f than the control group(P<0.05). In term of slow 0.51 × 10^-3mm^2/s in area of 1.00, sensitivity of 100% and specificity of 100% to discriminate the positive group from the control group, whereas Dfast=11.86×10^-3mm^2/s in 0.91,90.0%, 80.0% and f=0.41 in 0.95, 90.0%, 85.0% to differentiate the negative group from the control group. [Conclusion] The differential diagnosis value of Dslow is higher as no definite bone marrow edema is noted in the routine sequence MRI in early active AS, whereas the Dfast and f are higher valuable with definite bone marrow edema in routine sequence.