肝细胞癌IVIM和DCE-MRI定量评估及相关性分析

Quantitative Evaluation and Correlation Analysis of Hepatocellular Carcinoma with IVIM and DCE-MRI

目的采用体素内不相干运动(IVIM)扩散加权成像(DWI)及动态增强磁共振成像(DCE-MRI)定量评估肝细胞癌(HCC)的扩散及灌注特征,并分析两者参数之间的相关性。方法使用飞利浦1.5 T MR对37例HCC的患者行上腹部常规MRI及IVIM-DWI检查,其中25例同时完成了DCE-MRI检查,纳入HCC病灶50个。测量HCC病灶和背景肝实质的表观扩散系数(ADC)及IVIM参数真性扩散系数(D)、灌注相关的扩散系数(D*)、灌注分数(f)值,测量HCC的DCE-MRI定量参数容积转运常数(Ktrans)、回流速率常数(Kep)、血管外细胞外间隙容积分数(Ve)及血浆容积分数(Vp)。采用Student’s T test或Mann-Whitney U test比较肝实质和HCC的ADC值及IVIM参数值,采用Spearman相关分析评估HCC的IVIM参数与DCE-MRI参数之间的相关性。结果HCC的ADC、D、f、D*值均显著低于背景肝实质(t/Z-8.035~12.059,P<0.001)。D与Ve呈正相关(r=0.340,P=0.046),D*与Vp呈负相关(r=-0.418,P=0.024),而f、f×D*与DCE-MRI各参数间均无显著相关性(r-0.075~0.118,P>0.05)。结论HCC的ADC值及IVIM参数值显著低于背景肝实质;IVIM参数与DCE-MRI定量参数的相关性较弱,提示二者在反映HCC的微循环特征方面可能存在一定差异。

Objective To quantify the characteristics of hepatocellular carcinoma(HCC)with both intravoxel incoherent motion(IVIM)diffusion-weighted imaging(DWI)and dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI),and to evaluate the correlation between the resultant parameters.Methods 37 patients with HCC underwent routine MRI and IVIM-DWI scans using Philips 1.5 T MR,including 25 subjects who underwent DCE-MRI scans simultaneously.50 HCC lesions were enrolled.Apparent diffusion coefficient(ADC)and IVIM parameters including true diffusion coefficient(D),perfusion-related diffusion coefficient(D*)and perfusion fraction(f))of HCCs and background liver parenchyma were measured.Meanwhile,the quantitative DCE-MRI parameters of HCCs were extracted:volume transfer coefficient(Ktrans),reverse reflux rate constant(Kep),the volume fraction of extravascular extracellular space(Ve)and the volume fraction of intravascular plasma(Vp).ADC and IVIM parameters were compared between liver parenchyma and HCCs by using Student’s T test or Mann-Whitney U test.In addition,Spearman rank correlation analysis was performed to evaluate the relationship between parameters of IVIM and DCE-MRI perfusion parameters in HCCs.Results When compared with liver parenchyma,HCCs showed significantly lower ADC,D,f and D*values(P<0.001).Correlation analysis demonstrated that D showed significantly weak correlation with Ve(r=0.340,P=0.046),and D*was also negatively correlated with Vp(r=-0.418,P=0.024).However,no significant correlation was observed between f,f×D*and DCE-derived parameters(r-0.075~0.118,P>0.05).Conclusion ADC value and IVIM parameters of HCC are significantly lower than those of background liver parenchyma.The correlation between parameters of HCC from IVIM and DCE-MRI is weak,suggesting there may be differences in their microcirculation characteristics.