Hepatocellular Carcinoma: Imaging Patterns on Gadoxetic Acid-enhanced MR Images and Their Value as an Imaging Biomarker

Purpose: To investigate the patterns of imaging appearance of hepatocellular carcinoma (HCC) on gadoxetic acid-enhanced magnetic resonance (MR) images and to assess their potential value as prognostic markers of HCC associated with tumor recurrence after surgery. Materials and Methods: The institutional review board approved this retrospective study and informed consent was waived. A total of 216 patients with 304 pathologically proved HCCs underwent gadoxetic acid-enhanced MR imaging prior to surgery and were included in the study. Two reviewers, blinded to the clinical data, evaluated in consensus the imaging patterns of HCC according to enhancement patterns on dynamic phase images and signal intensity on hepatobiliary phase (HBP) images. The association of imaging features with clinical-pathologic findings was evaluated by using the Student t test, chi(2) test, Mann-Whitney U test, and linear-by-linear association. The dependence of time to tumor recurrence (TTR) after surgery was evaluated by using the Kaplan-Meier method, log-rank test, and Cox proportional hazard model. Results: HCCs with atypical enhancement pattern (P = .0167, P = .0450, P= .0001, respectively) and iso-to hyperintensity on HBP images (P = .0001, P = .0002, P= .0001, respectively) had smaller tumor size, lower histologic grade, and worse Child-Pugh class. The log-rank test (P = .0064) and Cox proportional hazards model (hazard ratio, 5.676; P = .0158) revealed that HCCs with iso-to hyperintensity on HBP images had significantly longer TTR than HCCs with hypointensity on HBP images. Conclusion: HCCs can be classified into several imaging patterns on gadoxetic acid-enhanced MR images, which are associated with tumor aggressiveness and outcome. In addition, iso-to hyperintensity on HBP images may be a useful imaging biomarker to indicate longer TTR after surgery.