基于磁共振扩散加权成像的虚拟弹性成像在肝脏局灶性病变中的应用价值

The application value of virtual magnetic resonance elastography based on diffusion weighted imaging in focal liver lesions

目的探究基于磁共振扩散加权成像(diffusion weighted imaging,DWI)的虚拟弹性成像(virtual magnetic resonance elastography,vMRE)在肝脏局灶性病变(focal liver lesion,FLL)的应用价值。材料与方法回顾性分析2021年11月至2022年6月于西安交通大学第一附属医院进行上腹部MRI检查的224例FLL患者临床及影像资料。所有患者的上腹部MRI检查序列包括常规抑脂T2WI(fat saturation T2WI,FS-T2WI)和多b值DWI,以病理或临床诊断结果将病例分为肝细胞癌、转移瘤、胆管细胞癌、血管瘤及肝囊肿五组。通过t检验或Mann-Whitney U检验比较各组间的测量值差异是否存在统计学意义,并绘制受试者工作特征(receiver operating characteristic,ROC)曲线评价vMRE的诊断效能。结果良恶性FLL的硬度值差异存在统计学意义(Z=-12.309,P<0.01),血管瘤与恶性病变的硬度值差异存在统计学意义(Z=-6.733,P<0.01)。vMRE鉴别良恶性FLL的敏感度为92.2%,特异度为96.7%,曲线下面积(area under the curve,AUC)为0.981;vMRE鉴别血管瘤与恶性病变的敏感度为92.2%,特异度为88.0%,AUC为0.926。血管瘤分别与肝细胞癌(Z=-6.232,P<0.01)、转移瘤(Z=-5.975,P<0.01)、胆管细胞癌(Z=-4.313,P<0.01)三组之间差异具有统计学意义。在恶性病变中,肝细胞癌组与转移瘤组差异无统计学意义(K=1.231,P>0.05);转移瘤组与胆管细胞癌组差异具有统计学意义(K=-2.062,P<0.05);肝细胞癌组与胆管细胞癌组差异无统计学意义(K=-1.403,P>0.05)。结论基于DWI的vMRE可作为一种无创性指标反映组织的硬度,有助于肝脏常见的良恶性病变鉴别诊断,可为临床中不典型血管瘤与恶性病变的鉴别诊断提供一种新型指标。

Objective:To explore the application value of virtual magnetic resonance elastography(vMRE)based on diffusion weighted imaging(DWI)in focal liver lesion(FLL).Materials and Methods:A retrospective analysis was made of 224 patients with FLL who underwent upper abdomen MRI in the First Affiliated Hospital of Xi'an Jiaotong University from November 2021 to June 2022.All patients upper abdominal MRI examination sequences including outine fat suppression T2WI(FS-T2WI)and multi b-value DWI.The study subjects were divided into five groups based on pathological or clinical diagnosis:hepatocellular carcinoma,metastatic tumor,cholangiocarcinoma,hemangioma,and liver cyst.Compare the measured values between groups for statistical differences using t-tests or Mann Whitney U-tests,and draw receiver operating characteristic(ROC)curves to evaluate the diagnostic efficacy of vMRE.Result:There was a statistically significant difference in the stiffness value of vMRE in distinguishing benign and malignant lesions(Z=-12.309,P<0.01),and there was a statistically significant difference in the stiffness value between differentiating hemangiomas and malignant lesions(Z=-6.733,P<0.01).The sensitivity,specificity and area under the curve(AUC)of virtual elastography were 92.2%,96.7%and 0.981 respectively in differentiating benign and malignant FLL.The sensitivity of virtual elastography in differentiating hemangioma from malignant lesions was 92.2%,the specificity was 88.0%,and the AUC was 0.926.There were statistical differences between hemangioma and hepatocellular carcinoma(Z=-6.232,P<0.01),metastatic tumor(Z=-5.975,P<0.01),and cholangiocarcinoma groups(Z=-4.313,P<0.01).In malignant lesions,there was no significant statistical difference between the hepatocellular carcinoma group and the metastatic tumor group(K=1.231,P>0.05),and the hepatocellular carcinoma group and the cholangiocarcinoma group(K=-1.403,P>0.05);There was a statistical difference between the metastatic tumor group and the cholangiocarcinoma group(K=-2.062,P<0.05).Conclusions:vMRE based on DWI is a non-invasive indicator that reflects the stiffness of tissues.It is helpful for the differential diagnosis of common benign and malignant liver lesions,and may provide a new indicator for the differential diagnosis of atypical hemangiomas and malignant lesions in clinical practice.