Supplementary Material for: Quality Assessment of Ultrasound and Magnetic Resonance Imaging for Hepatocellular Carcinoma Surveillance: A Systematic Review and Meta-Analysis

<b><i>Introduction:</i></b> To achieve early detection and curative treatment options, surveillance imaging for hepatocellular carcinoma (HCC) must remain of quality and without substantial limitations in liver visualization. However, the prevalence of limited liver visualization during HCC surveillance imaging has not been systematically assessed. Utilizing a systematic review and meta-analytic approach, we aimed to determine the prevalence of limited liver visualization during HCC surveillance imaging. <b><i>Methods:</i></b> MEDLINE and Embase electronic databases were searched to identify published data on liver visualization limitations of HCC surveillance imaging. An analysis of proportions was pooled using a generalized linear mixed model with Clopper-Pearson intervals. Risk factors were analysed using a generalized mixed model with a logit link and inverse variance weightage. <b><i>Results:</i></b> Of 683 records, 10 studies (7,131 patients) met inclusion criteria. Seven studies provided data on liver visualization limitations on ultrasound (US) surveillance exams: prevalence of limited liver visualization was 48.9% (95% CI: 23.5–74.9%) in the overall analysis and 59.2% (95% CI: 24.2–86.9%) in a sensitivity analysis for cirrhotic patients. Meta-regression determined that non-alcoholic fatty liver disease was associated with limited liver visualization on US. Four studies provided data for liver visualization limitations in abbreviated magnetic resonance imaging (aMRI), with inadequate visualization ranging from 5.8% to 19.0%. One study provided data for complete MRI and none for computed tomography. <b><i>Conclusion:</i></b> A substantial proportion of US exams performed for HCC surveillance provide limited liver visualization, especially in cirrhosis, which may hinder detection of small observations. Alternative surveillance strategies including aMRI may be appropriate for patients with limited US visualization.

**引言：** 为实现肝细胞癌（hepatocellular carcinoma，HCC）的早期检出与根治性治疗，肝细胞癌监测成像需保证成像质量且在肝脏可视化层面无显著局限。然而，目前尚未有研究对肝细胞癌监测成像过程中肝脏可视化受限的发生率开展系统评估。本研究采用系统评价与荟萃分析方法，旨在明确肝细胞癌监测成像中肝脏可视化受限的发生率。

**方法：** 检索MEDLINE与Embase电子数据库，以获取肝细胞癌监测成像肝脏可视化受限相关的已发表数据。采用广义线性混合模型（generalized linear mixed model）结合克洛珀-皮尔逊置信区间（Clopper-Pearson intervals）进行合并比例分析；采用带有logit连接函数与逆方差权重的广义混合模型分析危险因素。

**结果：** 在683条检索记录中，共10项研究（纳入7131例患者）符合纳入标准。其中7项研究提供了超声（ultrasound，US）监测成像的肝脏可视化受限相关数据：总体分析中肝脏可视化受限发生率为48.9%（95%置信区间：23.5%~74.9%），肝硬化患者敏感性分析中该发生率为59.2%（95%置信区间：24.2%~86.9%）。Meta回归分析显示，非酒精性脂肪性肝病（non-alcoholic fatty liver disease）与超声监测成像的肝脏可视化受限存在显著关联。4项研究提供了缩略磁共振成像（abbreviated magnetic resonance imaging，aMRI）的肝脏可视化受限相关数据，其可视化不足率为5.8%~19.0%。另有1项研究提供了完整MRI的相关数据，尚未检索到计算机断层扫描（computed tomography，CT）相关研究数据。

**结论：** 相当一部分用于肝细胞癌监测的超声检查存在肝脏可视化受限的情况，尤其在肝硬化患者中，这可能会阻碍微小病灶的检出。对于超声可视化受限的患者，采用包括缩略磁共振成像在内的替代监测策略或许是合适的选择。