Value of threshold growth as a major diagnostic feature of hepatocellular carcinoma in LI-RADS

Abstract

The Liver Reporting and Data System (LI-RADS) version 2018 simplified the definition of threshold growth to '≥50% size increase in a mass in ≤6 months. However, the diagnostic value of threshold growth for HCC remained unclear. We evaluated the value of threshold growth, as defined by the LI-RADS v2018, in diagnosing HCCs. Patients who underwent preoperative gadoxetate disodium-enhanced MRI because of the presence of LI-RADS category 2, 3, or 4 rather than category 5 on prior CT/MRI between January 2017 and December 2020 were retrospectively evaluated. Pathologic or clinical diagnoses were used as reference standards. Imaging features were evaluated by three readers according to LI-RADS v2018. The frequency and diagnostic odds ratio of threshold growth were calculated. The diagnostic performance of LI-RADS category 5 was separately evaluated when threshold growth was and was not considered a major feature, and results were compared using generalized estimation equations. Subgroups of patients who underwent CT/MRI during the previous 3-6 months were analyzed. Analysis of 340 observations in 243 patients found that the frequency of threshold growth was 18.8% and it gradually increased over time. Threshold growth was significantly associated with HCC 5.2 (95% confidence interval=2.1-12.7; p<0.001). Use of threshold growth as a major feature significantly increased sensitivity in both the overall (66.4% vs. 57.3%, p<0.001) and subgroup (73.4% vs. 58.2%, p<0.001) cohorts, but had no effect on specificity in either the overall (97.5% vs. 98.3%, p=0.319) or subgroup (95.9% vs. 98.0%, p=0.323) cohorts. The revised threshold growth of LI-RADS v2018 was significantly associated with HCC. Use of threshold growth as a major feature can improve the sensitivity for diagnosing HCC. We found that the revised threshold growth in the Liver Imaging Reporting and Data System version 2018 was a significant predictor of hepatocellular carcinoma (HCC). The use of threshold growth as a major imaging feature significantly increased the sensitivity of diagnosing HCC, especially small HCC (≤3.0cm), compared with its non-use. Because these small HCCs are eligible for curative treatments, the additional detection of small HCCs would be clinically meaningful.