Hepatocellular carcinoma (HCC) is the sixth most common malignant tumor worldwide, with a significantly increased incidence among patients with liver diseases. Even if HCC can be treated by surgical resection and ablation, the 5-year recurrence rate is as high as 50-70%. The Liver Imaging Reporting and Data System (LI-RADS), released by the American College of Radiology (ACR), is a classification management system specifically designed to evaluate liver lesions in high-risk HCC patients. Since its release in 2011, the CT/MRI LI-RADS has been updated to the 2018 version. Subsequently, the CEUS LI-RADS was introduced in 2016 and updated in 2017. The CEUS LI-RADS standard has relatively high specificity but lacks sensitivity. The ESCULAP (Erlanger Synopsis of Contrast-enhanced Ultrasound for Liver lesion Assessment in Patients at Risk) standard proposed by Schellhaas et al. in Germany has high sensitivity in diagnosing HCC in patients with liver diseases . However, there is currently a lack of research on the diagnostic efficacy of these two standards for the re-discovery of liver space-occupying lesions in patients with a history of HCC. This study aims to compare the diagnostic efficacy of the two standards for recurrent HCC in patients with a history of HCC.

This study is a cross-sectional study.

Inclusion Criteria:

• (1) At least 18 years old; (2) Has a previous history of liver cell cancer surgery or ablation, and has a newly developed liver lesion this time; (3) The new lesion completed a complete contrast-enhanced ultrasound examination within two weeks before the final diagnosis, and the dynamic imaging data is completely preserved; (4) The new lesion has a clear pathological or clinical diagnosis.

Exclusion Criteria:

• (1) The quality of contrast-enhanced ultrasound images is poor, making it impossible to assess the critical phases; (2) New lesions that have been treated locally or systemically.

The study population consisted of outpatients and inpatients who visit the Department of Abdominal Ultrasound at First Hospital of Jilin University and undergo liver contrast-enhanced ultrasound between May 2026 and May 2027.