From the Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, 81 Irwon-Ro Gangnam-gu, Seoul 06351, Republic of Korea (J.H.M., M.W.L., D.I.C.); Department of Health Sciences and Technology, SAIHST, Sungkyunkwan University, Seoul, Republic of Korea (M.W.L.); Department of Radiology, Konkuk University School of Medicine, Seoul, Republic of Korea (H.S.P.); Department of Radiology, Seoul National University Hospital, Seoul, Republic of Korea (D.H.L.); Department of Radiology, Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Republic of Korea (H.J.P.); Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea (S.L.); Department of Radiology, Soonchunhyang University College of Medicine, Bucheon Hospital, Bucheon, Republic of Korea (S.Y.C., J.E.L.); Department of Radiology, Chungbuk National University Hospital, Cheongju, Republic of Korea (J.L.); Department of Pathology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea (S.Y.H.); Department of Mathematical and Statistical Sciences University of Alberta, Edmonton, Canada (K.C.C.); Biostatics and Clinical Epidemiology Center, Research Institute for Future Medicine, Samsung Medical Center, Seoul, Republic of Korea (J.H.A.).
Radiology. 2020 Dec;297(3):573-581. doi: 10.1148/radiol.2020201940. Epub 2020 Sep 29.
Background Accurate identification of microvascular invasion (MVI) in hepatocellular carcinoma (HCC) before treatment is critical for selecting a proper treatment strategy. Purpose To evaluate the interobserver agreement and the diagnostic performance of the MRI assessment of MVI in HCC according to the level of radiologist experience. Materials and Methods This retrospective study included 100 patients with surgically confirmed HCCs smaller than 5 cm who underwent gadoxetic acid-enhanced MRI between 2013 and 2016. Eight postfellowship radiologists (four with 7-13 years of experience [more experienced] and four with 3-6 years of experience [less experienced]) evaluated four imaging features (nonsmooth tumor margin, irregular rim-like enhancement in the arterial phase, peritumoral arterial phase hyperenhancement, peritumoral hepatobiliary phase hypointensity) and assigned the possibility of MVI. Interobserver agreement was determined by using Fleiss κ statistics according to reviewer experience and tumor size (≤3 cm vs >3 cm). With reference standards of histopathologic specimens, the diagnostic performance in the identification of MVI was assessed by using receiver operating characteristic curve analysis. Results In 100 patients (mean age, 58 years ± 10 [standard deviation]; 70 men) with 100 HCCs (mean size, 2.8 cm ± 0.9), 39 (39%) HCCs had MVI. The overall interobserver agreement was fair to moderate for the imaging features and their combinations (κ = 0.38-0.47) and MVI probability (κ = 0.41; 95% confidence interval: 0.33, 0.45). More experienced reviewers demonstrated higher agreement in MVI probability than less experienced reviewers (κ = 0.55 vs 0.36, respectively; = .002). Diagnostic performance of each reviewer was modest for MVI prediction (area under the receiver operating characteristic curve [AUC] range, 0.60-0.74). The AUCs for the diagnosis of MVI were lower for HCCs larger than 3 cm (range, 0.55-0.69) than for those less than or equal to 3 cm (range, 0.59-0.75). Conclusion Considerable interobserver variability exists in the assessment of microvascular invasion in hepatocellular carcinoma using MRI, even for more experienced radiologists. © RSNA, 2020 See also the editorial by Tang in this issue.
背景 在治疗前准确识别肝细胞癌（HCC）中的微血管侵犯（MVI）对于选择合适的治疗策略至关重要。目的 评估根据放射科医生经验水平，MRI 评估 HCC 中 MVI 的观察者间一致性和诊断性能。
材料与方法 本回顾性研究纳入了 2013 年至 2016 年间接受钆塞酸增强 MRI 检查且肿瘤直径小于 5cm、经手术证实为 HCC 的 100 例患者。8 名完成住院医师培训后的放射科医生（4 名经验 7-13 年[经验更丰富]，4 名经验 3-6 年[经验较少]）评估了 4 种影像学特征（肿瘤边缘不光滑、动脉期不规则边缘样强化、肿瘤周围动脉期强化、肿瘤周围肝胆期低信号）并对 MVI 的可能性进行了评估。根据观察者经验和肿瘤大小（≤3cm 与＞3cm），使用 Fleiss κ 统计量评估观察者间一致性。以病理组织学标本为参考标准，采用受试者工作特征曲线分析评估对 MVI 的诊断性能。
结果 在 100 例患者（平均年龄 58 岁±10[标准差]；70 例男性）的 100 个 HCC 中，有 39 个（39%）HCC 存在 MVI。对于影像学特征及其组合（κ=0.38-0.47）和 MVI 概率（κ=0.41；95%置信区间：0.33，0.45），整体观察者间一致性为中等至良好。经验更丰富的观察者在 MVI 概率方面的一致性高于经验较少的观察者（κ=0.55 与 0.36，P＜.002）。每位观察者对 MVI 的预测诊断性能均为中等（受试者工作特征曲线下面积范围，0.60-0.74）。对于直径大于 3cm（范围，0.55-0.69）的 HCC，MVI 诊断的 AUC 低于直径小于或等于 3cm（范围，0.59-0.75）的 HCC。
结论 即使对于经验更丰富的放射科医生，使用 MRI 评估 HCC 中的 MVI 也存在相当大的观察者间差异。
