摘要目的:探讨磁共振表观扩散系数（ADC）值术前预测肝细胞癌（HCC）微血管侵犯（MVI）的可行性，并比较ADC平均值（ADC mean）和ADC最小值（ADC min）术前定量预测HCC MVI的诊断效能。 方法:检索PubMed、Embase、Web of Science、Cochrane Library和中国知网、万方数据库中关于磁共振ADC对HCC MVI诊断的相关研究，检索时间从建库至2020年10月。根据纳入与排除标准筛选文献，提取研究的基本特征和诊断参数，采用诊断试验质量评价工具-2量表对研究质量进行评分。绘制总受试者工作特征（SROC）曲线，计算曲线下面积（AUC），组间差异的比较采用Mann-Whitney U检验。采用Egger's漏斗图及独立样本 t检验比较纳入文献的发表偏倚。 结果:最终纳入13篇文献，共1432例HCC患者，2303个HCC病灶。MVI阳性病灶的ADC mean和ADC min明显低于MVI阴性病灶，组间的均数差分别为-0.17× 10 -3 mm 2/s [95% CI：（-0.23~-0.12）×10 -3 mm 2/s， Z=6.58， P<0.001]和-0.15×10 -3 mm 2/s [95% CI：（-0.18~-0.12）×10 -3 mm 2/s， Z=9.91， P<0.001]。以最大Youden指数确定ADC mean和ADC min术前诊断HCC MVI阳性的最佳阈值分别为1.11×10 -3 mm 2/s和0.959×10 -3 mm 2/s。ADC mean和ADC min术前定量预测HCC MVI阳性的合并灵敏度分别为0.74和0.65、特异度分别为0.69和0.68、SROC的AUC分别为0.7722和0.7326，差异均无统计学意义（ Z=-0.917、-0.525、-0.131，均 P>0.05）。亚组分析结果显示，发表年份、MVI阳性与阴性病灶数的比例及b值数可能为异质性来源。ADC mean和ADC min的Egger's漏斗图结果显示，差异均无统计学意义（无发表偏倚， t=-1.58、-0.71，均 P>0.05）。 结论:ADC值可作为一种可靠、无创的术前定量预测HCC MVI的检查指标。与ADC min相比，ADC mean术前定量预测HCC MVI阳性的诊断效能更优。

abstractsObjective:To investigate the feasibility of magnetic resonance apparent diffusion coefficient (ADC) value for preoperative quantitative prediction of microvascular invasion (MVI) in hepatocellular carcinoma (HCC) and to compare the diagnostic efficacy of ADC mean value (ADC mean) and ADC minimum value (ADC min) for preoperative quantitative prediction of MVI in HCC. Methods:PubMed, Embase, Web of Science, Cochrane Library, CNKI, and Wanfang data were researched from establishment to October 2020. Literature was screened in accordance with the inclusion and exclusion criteria; the basic characteristics and diagnostic parameters of the study were extracted, and the research quality was scored using the quality assessment of diagnostic accuracy studies-2 scale. The summary receiver operating characteristic (SROC) curve was drawn, and the area under curve (AUC) was calculated. In addition, the Mann-Whitney U test was used to compare the differences among the groups. Egger's funnel chart and independent sample t test were used to compare the publication bias for the included literature. Results:A total of 13 up-to-standard literature with 1432 cases of HCC (2303 lesions of HCC) were included in the meta-analysis. ADC mean and ADC min in MVI-positive lesions were significantly lower than those in MVI-negative lesions, with mean differences of-0.17×10 -3 mm 2/s (95% CI: (-0.23 - -0.12)×10 -3 mm 2/s, Z=6.58, P<0.001) and-0.15×10 -3 mm 2/s (95% CI: (-0.18 - -0.12)×10 -3 mm 2/s, Z=9.91, P<0.001), respectively. Moreover, the best cutoff values of ADC mean and ADC min for preoperative diagnosis of HCC MVI were 1.11×10 -3 mm 2/s and 0.959×10 -3 mm 2/s, respectively, based on the maximum Youden index. The pooled sensitivity of ADC mean and ADC min in the preoperative quantitative prediction of MVI-positive lessions with HCC was 0.74 and 0.65; the specificity was 0.69 and 0.68, and SROC AUC was 0.7722 and 0.7326, respectively. However, this result showed no significant difference ( Z=-0.917, -0.525,-0.131; all P>0.05). Furthermore, subgroup analysis showed that the year of publication, MVI positive and negative ratio, and the number of b-values might cause heterogeneity, and Egger's funnel plots of ADC mean and ADC min showed no statistically significance (no publication bias; t=-1.58,-0.71; both P>0.05). Conclusions:The ADC value can be used as a reliable and noninvasive indicator for preoperative quantitative prediction of MVI in HCC. Compared with ADC min, ADC mean has superior diagnostic efficacy in predicting MVI-positive patients with HCC.