Gadoxetic acid-enhanced MRI of macrotrabecular-massive hepatocellular carcinoma and its prognostic implications

Background & Aims: Despite the clinical and genetic significance of macrotrabecular-massive hepatocellular carcinoma (MTM-HCC), its characteristics on imaging have not been described. This study aimed to characterise MTM-HCC on gadoxetic acid-enhanced MRI and to evaluate the diagnostic accuracy and prognostic value of these imaging characteristics. Methods: We enrolled 3 independent cohorts from 2 tertiary care centres. The 3 cohorts consisted of a total of 476 patients who underwent gadoxetic acid-enhanced MRI and surgical resection for treatment-naive single HCCs. Independent review of histopathology and MRI by 2 reviewers was performed for each cohort, and inter-reader agreement was evaluated. Based on the result of MRI review in the training cohort (cohort 1), we developed 2 diagnostic criteria for MTM-HCC and evaluated their prognostic significance. The diagnostic performance and prognostic significance were validated in 2 validation cohorts (cohorts 2 and 3). Results: We developed 2 diagnostic MRI criteria (MRIC) for MTM-HCC: MRIC-1, >= 20% arterial phase hypovascular component; MRIC-2, >= 50% hypovascular component and 2 or more ancillary findings (intratumoural artery, arterial phase peritumoural enhancement, and non-smooth tumour margin). MRIC-1 showed high sensitivity and negative predictive value (88% and 95% in the training cohort, and 88% and 97% in the pooled validation cohorts, respectively), whereas MRIC-2 demonstrated moderate sensitivity and high specificity (47% and 94% in the training cohort, and 46% and 96% in the pooled validation cohorts, respectively). MRIC-2 was an independent poor prognostic factor for overall survival in both training and pooled validation cohorts. Conclusions: Using gadoxetic acid-enhanced MRI findings, including an arterial phase hypovascular component, we could stratify the probability of MTM-HCC and non-invasively obtain prognostic information. Lay summary: Macrotrabecular-massive hepatocellular carcinoma (MTM-HCC) is a histopathologic subtype of HCC characterised by aggressive biological behaviour and poor prognosis. We developed imaging criteria based on liver MRI that could be used for the non-invasive diagnosis of MTM-HCC. HCCs showing imaging findings of MTM-HCC were associated with poor outcomes after hepatic resection. (C) 2020 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

Automated summary

This study aimed to characterize MTM-HCC on gadoxetic acid-enhanced MRI and evaluate the diagnostic accuracy and prognostic value of these imaging characteristics. Two diagnostic criteria were developed for MTM-HCC based on MRI findings which showed good sensitivity and specificity, and were associated with poor outcomes after hepatic resection.