Non-hypervascular hepatobiliary phase hypointense nodules on gadoxetic acid-enhanced MRI: risk of HCC recurrence after radiofrequency ablation.

BACKGROUND & AIMS: Hepatobiliary phase images (HBPI) of gadoxetic acid-enhanced MRI can depict borderline hepatocellular nodules that have the potential to progress into hypervascular hepatocellular carcinomas (HCCs), as non-hypervascular hypointense nodules. We retrospectively evaluated the impact of the presence of non-hypervascular hypointense nodules at HBPI of gadoxetic acid-enhanced MRI on the patient's prognosis after radiofrequency ablation (RFA) for early stage HCCs.
METHODS: A total of 139 patients who underwent pre-procedural gadoxetic acid-enhanced MRI followed by RFA were included. After a mean follow-up of 44.6±13.2 months, we compared the results of tumor recurrence as well as overall and recurrence-free survival (RFS) with the presence of non-hypervascular hypointense nodules on HBPI.
RESULTS: The presence of non-hypervascular hypointense nodules on HBPI did not affect overall survival (p=0.136). However, the estimated 5-year RFS rate was 71.3% in 29 patients without non-hypervascular hypointense nodules on HBPI compared to 27.9% in 110 patients with non-hypervascular hypointense nodules on HBPI, indicating a significant difference (hazard ratio=2.84 [1.39-5.98], p=0.006). When we classified recurrence into local tumor progression [LTP], intrahepatic distant recurrence [IDR], and extra-hepatic metastasis [EM], five-year cumulative incidences (CI) of IDR in patients with non-hypervascular hypointense nodules on HBPI were significantly higher than those in patients without non-hypervascular hypointense nodules on HBPI (17.9% vs. 67.5%, p<0.001). Five-year CIs of LTP and EM showed no significant difference (p>0.05).
CONCLUSIONS: The presence of non-hypervascular hypointense hepatocellular nodules on HBPI of gadoxetic acid-enhanced MRI taken prior to RFA is a significant predictive factor of recurrence after RFA of early stage HCCs, particularly IDR.