Department of Diagnostic Imaging, Juravinski Hospital and Cancer Centre, Hamilton Health Sciences, McMaster University, Hamilton, Ontario, Canada.
Division of Abdominal Imaging and Intervention, Department of Radiology, Brigham Women's Hospital, Harvard Medical School, Boston, Massachusetts; Liver Imaging Group, Department of Radiology, University of California-San Diego. San Diego, California.
Gastroenterology. 2019 Mar;156(4):976-986. doi: 10.1053/j.gastro.2018.11.020. Epub 2018 Nov 13.
BACKGROUND & AIMS: The Liver Imaging Reporting and Data System (LI-RADS) categorizes observations from imaging analyses of high-risk patients based on the level of suspicion for hepatocellular carcinoma (HCC) and overall malignancy. The categories range from definitely benign (LR-1) to definitely HCC (LR-5), malignancy (LR-M), or tumor in vein (LR-TIV) based on findings from computed tomography or magnetic resonance imaging. However, the actual percentage of HCC and overall malignancy within each LI-RADS category is not known. We performed a systematic review to determine the percentage of observations in each LI-RADS category for computed tomography and magnetic resonance imaging that are HCCs or malignancies.
We searched the MEDLINE, Embase, Cochrane CENTRAL, and Scopus databases from 2014 through 2018 for studies that reported the percentage of observations in each LI-RADS v2014 and v2017 category that were confirmed as HCCs or other malignancies based on pathology, follow-up imaging analyses, or response to treatment (reference standard). Data were assessed on a per-observation basis. Random-effects models were used to determine the pooled percentages of HCC and overall malignancy for each LI-RADS category. Differences between categories were compared by analysis of variance of logit-transformed percentage of HCC and overall malignancy. Risk of bias and concerns about applicability were assessed with the Quality Assessment of Diagnostic Accuracy Studies 2 tool.
Of 454 studies identified, 17 (all retrospective studies) were included in the final analysis, consisting of 2760 patients, 3556 observations, and 2482 HCCs. The pooled percentages of observations confirmed as HCC and overall malignancy, respectively, were 94% (95% confidence interval [CI] 92%-96%) and 97% (95% CI 95%-99%) for LR-5, 74% (95% CI 67%-80%) and 80% (95% CI 75%-85%) for LR-4, 38% (95% CI 31%-45%) and 40% (95% CI 31%-50%) for LR-3, 13% (95% CI 8%-22%) and 14% (95% CI 9%-21%) for LR-2, 79% (95% CI 63%-89%) and 92% (95% CI 77%-98%) for LR-TIV, and 36% (95% CI 26%-48%) and 93% (95% CI 87%-97%) for LR-M. No malignancies were found in the LR-1 group. The percentage of HCCs and overall malignancies confirmed differed significantly among LR groups 2-5 (P < .00001). Patient selection was the most frequent factor that affected bias risk, because of verification bias and case-control study design.
In a systematic review, we found that increasing LI-RADS categories contained increasing percentages of HCCs and overall malignancy based on reference standard confirmation. Of observations categorized as LR-M, 93% were malignancies and 36% were confirmed as HCCs. The percentage of HCCs found in the LR-2 and LR-3 categories indicate the need for a more active management strategy than currently recommended. Prospective studies are needed to validate these findings. PROSPERO number CRD42018087441.
肝脏影像报告和数据系统（LI-RADS）根据肝细胞癌（HCC）和整体恶性肿瘤的可疑程度对高危患者的影像学分析结果进行分类。类别范围从绝对良性（LR-1）到绝对 HCC（LR-5）、恶性（LR-M）或静脉内肿瘤（LR-TIV），这是基于计算机断层扫描或磁共振成像的发现。然而，每个 LI-RADS 类别中的 HCC 和整体恶性肿瘤的实际百分比尚不清楚。我们进行了一项系统评价，以确定每个 LI-RADS 类别中基于计算机断层扫描和磁共振成像的 HCC 或恶性肿瘤的观察百分比。
我们从 2014 年到 2018 年在 MEDLINE、Embase、Cochrane CENTRAL 和 Scopus 数据库中搜索了报道根据病理学、随访影像学分析或对治疗的反应（参考标准）确认每个 LI-RADS v2014 和 v2017 类别中观察结果为 HCC 或其他恶性肿瘤的百分比的研究。数据是基于每个观察进行评估的。使用随机效应模型确定每个 LI-RADS 类别的 HCC 和整体恶性肿瘤的汇总百分比。使用 HCC 和整体恶性肿瘤的对数转换百分比的方差分析比较类别之间的差异。使用诊断准确性研究质量评估工具 2 评估偏倚风险和适用性问题。
在确定的 454 项研究中，有 17 项（均为回顾性研究）最终纳入分析，共纳入 2760 名患者、3556 项观察和 2482 例 HCC。分别根据参考标准确认为 HCC 和整体恶性肿瘤的观察百分比的汇总百分比分别为 94%（95%置信区间 [CI] 92%-96%）和 97%（95%CI 95%-99%）为 LR-5，74%（95%CI 67%-80%）和 80%（95%CI 75%-85%）为 LR-4，38%（95%CI 31%-45%）和 40%（95%CI 31%-50%）为 LR-3，13%（95%CI 8%-22%）和 14%（95%CI 9%-21%）为 LR-2，79%（95%CI 63%-89%）和 92%（95%CI 77%-98%）为 LR-TIV，36%（95%CI 26%-48%）和 93%（95%CI 87%-97%）为 LR-M。LR-1 组未发现恶性肿瘤。LR 组 2-5 之间 HCC 和整体恶性肿瘤的确认百分比差异显著（P <.00001）。由于验证偏倚和病例对照研究设计，患者选择是影响偏倚风险的最常见因素。
在一项系统评价中，我们发现根据参考标准确认，LI-RADS 分类增加的类别包含了越来越多的 HCC 和整体恶性肿瘤。在归类为 LR-M 的观察中，93%为恶性肿瘤，36%被确认为 HCC。LR-2 和 LR-3 类别中发现的 HCC 百分比表明需要比目前推荐的更积极的管理策略。需要前瞻性研究来验证这些发现。PROSPERO 编号 CRD42018087441。
