Performance of contrast-enhanced ultrasound liver imaging reporting and data system for differentiation of patients at risk of hepatocellular carcinoma and liver metastasis.

Background: Hepatocellular carcinoma (HCC) and metastatic liver tumors (MLT) are the most common malignant liver lesions, each requiring distinct therapeutic approaches. Accurate differentiation between these malignancies is critical for appropriate treatment planning and prognostication. However, there is limited data on the performance of contrast-enhanced ultrasound liver imaging reporting and data system (CEUS-LI-RADS) in this differentiation.

Objective: To evaluate the diagnostic efficacy of the CEUS-LI-RADS in distinguishing between HCC and MLT in an expanded population at risk for both tumors.

Methods: Between June 2017 and January 2022, 108 patients with HCC and 138 patients with MLT who were pathologically diagnosed, where included in this retrospective study. Two radiologists independently reviewed the CEUS features and liver imaging reporting and data system (LI-RADS) categories of the lesions, and based on their consensus, we calculated the diagnostic performance, including the area under the receiver operating characteristic curve, sensitivity, specificity, and accuracy of the CEUS-LI-RADS criteria.

Results: The sensitivity, specificity, and accuracy of CEUS LI-RADS category 5 (CEUS-LR-5) for predicting HCC were 49.1% [95% confidence interval (CI)) 39.3-58.9], 97.1% (95% CI 92.7-99.2), and 76%, respectively, whereas the corresponding values for LI-RADS category M (LR-M) for diagnosing MLT were 89.1% (95%CI 82.7-93.8), 72.2% (95%CI 62.8-80.4), and 81.7%, respectively. Based on current LR-M criteria, a small proportion of HCCs were classified as LR-M due to the presence of early cessation (45-60s). In the analysis of the MLT subgroup, we found that the tumor size affects the distribution of LI-RADS (LR) classification in the subgroup (p = 0.037), and LI-RADS category 3 (LR-3) classification was observed more frequently in tumors of small size (≤3cm) than those of larger size. In addition, LR-3 metastases were more frequently characterized by hypovascular supply.

Conclusions: CEUS-LI-RADS demonstrates high specificity in distinguishing HCC from MLT, providing a reliable noninvasive diagnostic tool that can enhance clinical decision-making. These findings are clinically significant as they can improve patient management and treatment outcomes, and they underscore the need for future research to refine and expand the use of CEUS-LI-RADS in diverse clinical settings.