探讨美国放射学会超声造影（CEUS）肝脏影像报告与数据系统（LI-RADS）LR-5类标准联合甲胎蛋白（AFP）在有无高危因素背景人群中对肝细胞癌（HCC）的诊断价值。

回顾性分析2018年10月至2020年10月于浙江大学医学院附属第二医院就诊的共574例患者的592个肝内局灶性病变的CEUS及AFP等临床资料，病灶均经过病理或影像学随访证实。若患者有乙型肝炎、肝硬化、HCC既往史等HCC高风险因素则归为高危风险组，无高风险因素者归入无高危风险组，无高危风险组中符合代谢相关脂肪性肝病（MAFLD）患者归入无高危MAFLD组。根据CEUS LI-RADS v2017分类标准对所有结节进行分类。联合AFP后高危风险组具有以下任一特点诊断为HCC：（1）LR-5类；（2）LR-3、4类且AFP≥20 μg/L；（3）LR-M类中造影表现为动脉期高增强、出现廓清时间为30~60 s、120 s内呈轻度或无廓清且AFP≥20 μg/L；（4）LR-M类且AFP≥400 μg/L；无高危风险组及无高危MAFLD组符合LR-5类表现且AFP≥20 μg/L时诊断为HCC。绘制受试者操作特征（ROC）曲线，分别计算各组CEUS LI-RADS LR-5类标准联合AFP前后诊断HCC的效能，并采用χ²检验或Delong's检验比较各组内两种诊断效能的差异。

592个结节的病理学结果中，HCC 180个，非HCC恶性病变257个，良性病变155个。高危风险组LR-5类联合AFP相比于LR-5类单独诊断HCC的敏感度、ROC曲线下面积明显提高（74.36% vs 58.33%，0.854 vs 0.781），差异具有统计学意义（χ²=8.268，P=0.004；χ²=4.695，P<0.001）。无高危风险组和无高危MAFLD组LR-5类联合AFP与LR-5类单独诊断HCC相比AUC减小（0.583 vs 0.765，0.571 vs 0.754），2组联合诊断效能下降，差异具有统计学意义（Z=3.598、3.344，P均<0.001）。

ACR CEUS LI-RADS系统在高危风险人群中具有较高的诊断价值，联合不同水平AFP使用可以使效能进一步提升，但在无高危因素下可否联合AFP诊断HCC仍有待进一步研究。

To assess the value of the combination of the American College of Radiology (ACR)'s contrast-enhanced ultrasound (CEUS) liver imaging reporting and data system (LI-RADS) category LR-5 criteria and alpha-fetoprotein (AFP) in the diagnosis of hepatocellular carcinoma (HCC) among populations with and without high-risk factors.

A retrospective analysis was performed on the CEUS and AFP data for 592 intrahepatic focal lesions in 574 patients who were treated at the Second Affiliated Hospital of Zhejiang University School of Medicine from October 2018 to October 2020. All lesions were confirmed through pathological examination or imaging follow-up. Patients with high-risk factors for HCC such as hepatitis B, cirrhosis, or a history of HCC were classified into a high-risk group, while those without these high-risk factors were categorized into a non-high-risk group. In the non-high-risk group, patients meeting the criteria for metabolic associated fatty liver disease (MAFLD) were further classified into a non-high-risk MAFLD subgroup. All nodules were categorized according to the CEUS LI-RADS v2017 classification criteria. After combined AFP, in the high-risk group, a diagnosis of HCC was made if any of the following criteria were met: (1) categorized as LR-5; (2) categorized as LR-3 or LR-4 with an AFP level ≥20 μg/L; (3) categorized as LR-M with contrast enhancement characteristics including arterial phase hyperenhancement, washout appearance within 30-60 seconds, and mild or no washout within 120 seconds, combined with an AFP level ≥20 μg/L; (4) categorized as LR-M with an AFP level ≥400 μg/L. In the non-high-risk group and the non-high-risk MAFLD subgroup, a diagnosis of HCC was made when the criteria for LR-5 were met along with an AFP level ≥20 μg/L. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the diagnostic efficacy of CEUS LI-RADS category LR-5 criteria combined with AFP for HCC across different groups. The diagnostic performance of CEUS LI-RADS LR-5 criteria, alone or in combination with AFP, was calculated for each group. The chi-square (χ²) test or Delong's test was used to compare the differences in diagnostic efficacy between the two diagnostic approaches within each group.

Out of the 592 nodules, pathological results identified 180 as HCC lesions, 257 as non-HCC malignant lesions, and 155 as benign lesions. In the high-risk group, the combination of LR-5 category and AFP significantly improved the sensitivity and the area under the ROC curve (AUC) for diagnosing HCC compared to using the LR-5 category alone (74.36% vs 58.33% and 0.854 vs 0.781, respectively, χ²=8.268, P=0.004 and χ²=4.695, P<0.001). In the non-high-risk group and the non-high-risk MAFLD subgroup, the AUC of the combination of LR-5 category and AFP in diagnosing HCC decreased significantly compared to using the LR-5 category alone (0.583 vs 0.765 and 0.571 vs 0.754, respectively, Z=3.598, 3.344, P<0.001 for both).

ACR CEUS LI-RADS demonstrates substantial diagnostic value for HCC in high-risk populations, and its efficacy can be further enhanced by combining it with AFP levels at various thresholds. However, the effectiveness of ACR CEUS LI-RADS combined with AFP in the diagnosis of HCC in populations without high-risk factors remains to be further investigated.