Recurrence after Curative Resection of HBV‐related Hepatocellular Carcinoma: Diagnostic Algorithms on Gadoxetic Acid‐enhanced MRI

Small recurrent hepatocellular carcinoma (HCC) can show more atypical imaging patterns, and a specific diagnostic algorithm for HCC is lacking. The study aimed to better characterize postoperative recurrent HCC <20 mm in size with gadoxetic acid-enhanced MR imaging. We retrospectively evaluated 373 newly developed nodules after hepatectomy in 204 HCC patients with chronic hepatitis B virus (HBV) infection. The diagnostic performance of LI-RADS v2018 was calculated with gadoxetic acid-enhanced MRI to characterize recurrent HCC. Modified diagnostic algorithms were proposed by combining significant imaging biomarkers related to subcentimeter and 10-20 mm recurrence and were then compared with the LI-RADS system. A total of 256 recurrent HCCs (108 recurrent HCCs <10 mm in size; 148 recurrent HCCs 10-19 mm in size) were confirmed via histology or follow-up imaging. Nonrim arterial phase hyperenhancement and three LI-RADS ancillary features (hepatobiliary phase hypointensity, mild-moderate T2 hyperintensity and restricted diffusion) were significantly related to recurrent HCCs <20 mm in size according to multivariate analyses. For subcentimeter recurrence, combining at least two of the three ancillary features only achieved better specificity (sensitivity: 83.3%; specificity: 87.7%) than the LR-4 category (sensitivity: 88.9%, P=0.21; specificity: 70.8%, P=0.006). For 10-19 mm recurrence, combining nonrim arterial phase hyperenhancement and at least one of the three ancillary features achieved only a significantly enhanced sensitivity of 85.1% but a lower specificity of 86.5% compared with the LR-5 category (sensitivity: 63.5%, P<0.001; specificity: 94.2%, P=0.13). In conclusion: the diagnostic algorithms for subcentimeter and 10-19 mm recurrent HCCs should be stratified. Combining at least two ancillary features demonstrated comparable sensitivity with significantly enhanced specificity compared with the LR-4 category for characterizing subcentimeter recurrence.