常规MRI、DWI和动态增强扫描在肝脏局灶性病变诊断中的应用

The application of conventional MRI, DWI and DCEI in focal liver lesions

目的评价1.5 T MRI常用检查序列:常规T2WI、DWI、动态增强扫描(DCEI)在肝脏局灶性病变(FLLs)诊断中的应用价值。材料与方法由2名研究者分析23例FLLs患者肝脏T2WI、DWI和DCEI图像,按Couinaud八段分法分别记录所有检出的病灶并测量其直径,将结果与"标准诊断"对照,计算单独应用T2WI、DWI和DCEI,以及DCEI联合DWI四种检查方法的病灶检出率。对所有检出的病灶按5分法对其良恶性进行评分,作受试者工作特征(ROC)曲线分析。采用SPSS 16.0统计软件和SASS统计软件包对数据进行统计学分析,P≤0.05差异有统计学意义。结果 T2WI、DWI、DCEI三种方法检出率两两比较,DWI序列对直径≤5 mm病灶检出率较T2WI低(P=0.004),其余三种检查方法的各项检出率之间的差异均无统计学意义(P≥0.052)。DCEI联合DWI的各项检出率均为100%,总检出率均较T2WI、DWI和DCEI序列单独应用时高,且差异有统计学意义(P≤0.006);对良性病灶和直径≤5 mm病灶的检出率较DWI高,差异有统计学意义(P≤0.029)。DCEI联合DWI的Az值(0.982)最大,与DCEI间差异无统计学意义(P=0.075),与DWI、T2WI间的差异有统计学意义(P≤0.0199)。结论单独运用DWI或DCEI序列相对于常规T2WI,并不能提高MRI对FLLs的检出率。DCEI联合DWI序列相对于单独应用T2WI、DWI或DCEI序列能提高MRI对FLLs的总检出率。DCEI联合DWI相对于DWI序列能提高良性病灶和直径≤5 mm病灶的检出率,提高了MRI对FLLs的诊断效能。

Objective： The purpose of this study was to compare the diagnostic performances of conventional respiratory triggered T2WI, DWI and dynamic contrast enhanced imaging sequences in the evaluation of focal liver lesions （FLLs）. Materials and Methods：We collected liver MRI data of twenty-three patients from 2011.9 to 2013.1. Two observers reviewed T2WI, DWI and DCEI for FLLs detection and characterization, then compared T2WI, DWI, DCEI and DCEI combined with DWI for FLLs detection. The reviewers then characterized each detected lesion using a 5-point scale, the sensitivity, speciifcity and areas under the receiver operating characteristic curve （Az） for the detection of liver lesions were evaluated using receiver operating characteristic analysis. Results：Overall detection rate was equal for T2WI, DWI and DCEI, but ≤5 mm lesions detection rate was lower for DWI （44.44%） versus T2-weighted imaging （66.67%） （P=0.004）. Overall detection rate of DCEI combined with DWI （100%） was signiifcantly higher than T2WI （87.14%）, DWI （88.57%） and DCEI （87.14%） alone （P≤0.006）. Benign and≤5 mm lesions detection rate are higher for DCEI combined with DWI （100%、100%）versus DWI （87.23%、44.44%） （P≤0.029）. There was no significant difference between the three image sets （T2WI, DWI,DCEI） in the detection of FLLs with regards to Az （≥0.075）. However, the Az values of DCEI combined with DWI （0.982） was signiifcantly higher than those of DWI （0.886） and T2WI （0.858） （P≤0.0199）. Conclusions：The diagnostic performance of DCEI and DWI is equal to conventional respiratory triggered T2WI. Combination of DCEI and DWI increases the lesions detection and diagnostic performance.