目的 评价磁共振弥散加权成 像(DWI)在肝硬化背景下对小肝癌的诊 断价值。方法 在PubMed、EMBASE、Web of science、The Cochrane Library、 中国知网、维普数据、万方数据及中国 生物医学文献数据库上，计算机检索 1990年5月至2015年5月有关DWI在肝硬 化背景下诊断小肝癌的文献，由两位研 究者根据纳入与排除标准独立筛选文 献、获取资料，采用诊断精确性研究的 质量鉴定法(QUADAS-2)进行质量评价以 及Meta-Disc 1.4软件进行Meta分析， 提取数据合并灵敏度、特异度、阳性似 然比、阴性似然比，绘制综合受试者工 作特征(summary receiving operating characteristic,SROC)曲线，计算曲线 下面积(area under the curve,AUC)， 并进行亚组分析。结果 符合纳入标准 的共有5篇文献，纳入研究病人总数359 人，病灶数共444个。DWI汇总的灵敏 度为0.91(95%CI:0.89-0.93)，汇总的 特异度为0.91(95%CI:0.87-0.94)，汇 总的阳性似然比为8.39 (95%CI:5.59- 1 2 . 6 1 ) ， 汇 总 的 阴 性 似 然 比 0 . 0 7 (95%CI:0.04-0.15)，SROC曲线下面积 AUC为0.9631(Q*=0.9091)。在亚组分 析中，直径≤2cm的小肝癌组合并后的 灵敏度为89%，特异度为91%，AUC为 0.9565(Q*=0.8995)。结论 在常规MRI增 强的基础上，应用DWI对肝硬化背景下 小肝癌有较高的诊断价值，并且对直径 ≤2cm的小肝癌也有较好的诊断效能。

Objective To perform a meta-analysis of Diffusion-Weighted Imaging as a diagnostic tool for small hepatocellular carcinoma(HCC) in patients with cirrhosis. Methods A computer-based retrieval system was first used to identify reports on the diagnostic efficacy of Diffusion-Weighted Imaging for small HCC in patients with cirrhosis that were published between May 1990 and May 2015 in the following literature databases, including PubMed, EMBASE, Web of science, The Cochrane Library, China National Knowledge Infrastructure(CNKI), VIP Journal Integration Platform(VJIP), Wanfang Chinese Periodical Database, and Chinese Biomedicine Database(CBM). Two investigators, working independently, then selected cases from the relevant based on specific inclusion and exclusion criteria. The extracted data was subjected to quality assessment of diagnostic accuracy studies (QUADAS-2). The MetaDisc version 1.4 software was used to conduct meta-analyses, and subgroup analyses were performed. Results 5 studies were included in this meta-analysis with a total of 359 patients and 444 lesions. Diagnosis of small HCC in patients with cirrhosis By DWI had pooled sensitivity of 0.91 (95%CI:0.89-0.93), pooled specificity of 0.91 (95%CI:0.87-0.94), pooled positive likelihood ratios of 8.39 (95%CI:5.59-12.61), pooled negative likelihood ratios of 0.07 (95%CI:0.04-0.15), respectively. The area under the curve of the summary receiving operating characteristic (SROC) of DWI was 0.9631 (Q*=0.9091). In the subgroup analysis, the sensitivity of less than 2cm for small hepatocellular carcinoma combined was 89%, the specificity was 91%, AUC was 0.9565 (Q*=0.8995). Conclusion Combined use of DWl with conventional MRI could be valuable diagnostic tool for small HCC in cirrhotic patients.Furthermore, DWI could provide additional valuable information for small HCC(≤2.0cm)．