IVIM-DWI联合DCE-MRI诊断直肠癌盆腔淋巴结转移的价值

Diagnostic value of the combination of IVIM-DWI and DCE-MRI in pelvic lymphatic metastasis of rectal cancer

目的探讨体素内不相干运动扩散加权成像(intravoxel incoherent motion diffusion-weighted imaging,IVIM-DWI)及动态对比增强磁共振成像(dynamic contrastenhanced magnetic resonance imaging,DCE-MRI)对直肠癌盆腔淋巴结转移的诊断价值。材料与方法比较经手术病理证实的45例直肠癌患者盆腔转移组淋巴结(35枚)与非转移组淋巴结(28枚)的IVIM参数[表观扩散系数(apparent diffusion coefficient,ADC)、D、D^*及f值]和DCE-MRI参数(K^trans、Ve及Kep值)。比较正性和负性重构血管的斑块面积、负荷,观察责任斑块位置、分布及强化特点。结果转移组淋巴结的D及D*值明显低于非转移组,f值明显高于非转移组(P<0.05)。转移组淋巴结的K^trans及Ve值高于非转移组(P<0.05)。IVIM-DWI、DCE-MRI参数中纳入Logistic回归方程的因素分别为D值及K^trans值。受试者工作特征(reciver operating characteristic,ROC)曲线分析D值、K^trans值及二者联合诊断盆腔淋巴结转移的曲线下面积(area under curve,AUC)分别为0.822、0.789及0.923;敏感性分别为68.6%、85.7%及91.4%;特异性分别为85.7%,67.9%及82.1%。结论IVIM-DWI的D值及DCE-MRI的K^trans值对直肠癌盆腔淋巴结转移具有较高诊断价值,两者联合应用可提高诊断效能。

Objective:To investigate the value of intravoxel incoherent motion diffusionweighted imaging(IVIM-DWI)and dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI)in the identification of pelvic lymphatic metastasis in rectal cancer.Materials and Methods:63 pelvic lymph nodes of 45 patients with rectal cancer were divided into metastasis group(35 pieces)and non-metastasis group(28 pieces)by pathology,and the parameters of IVIM(ADC,D,D*and f values)and DCE-MRI(K^trans,Ve and Kep values)of the two groups were compared.Results:The mean D and D*value of metastatic lymph nodes were significantly lower than those of non-metastatic lymph nodes,and the mean f value of metastatic lymph nodes was significantly higher than that of non-metastatic lymph nodes(P<0.05).The mean K^trans and Ve value of metastatic lymph nodes were higer than those of non-metastatic lymph nodes(P<0.05).The factors adopted in the Logistic regression equation of IVIM-DWI and DCE-MRI were D value and K^trans value respectively.The AUC of D,K^trans value and their combination to diagnose pelvic lymph node metastasis were 0.822,0.789 and 0.923,respectively.The sensitivity in diagnosing pelvic lymph node metastasis of the three methods were 68.6%,85.7%and 91.4%,and the specificity were 85.7%,67.9%and 82.1%,respectively.Conclusions:D value of IVIMDWI and K^trans value of DCE-MRI have great value in diagnosing pelvic lymphatic metastasis in rectal cancer,and the combination of the two methods might improve the diagnostic efficiency.