Irregular Defects in Hepatocellular Carcinomas During the Kupffer Phase of Contrast-Enhanced Ultrasonography with Perfluorobutane Microbubbles: Pathological Features and Metastatic Recurrence After Surgical Resection

The present study aimed to elucidate the association between post-vascular-phase (Kupffer-phase) images from contrast-enhanced ultrasonography (CEUS) with perfluorobutane microbubbles and metastatic recurrences after the resection of hepatocellular carcinoma (HCC). The study examined 73 patients with solitary HCC ≤5 cm in diameter who underwent CEUS before resection. HCC was defined as irregular type (including an irregular defect on Kupffer-phase images) or non-irregular type. Intrahepatic metastatic recurrence was defined as >3 intrahepatic recurrences. Metastatic recurrence included both extrahepatic and intrahepatic recurrences. Frequencies of microscopic portal invasion and intrahepatic metastasis were significantly higher in the irregular group than in the non-irregular group. Cumulative 5-y metastatic recurrence rates in the irregular and non-irregular groups were 43% and 7% (p = 0.028), respectively. Multivariate analyses identified Kupffer-phase findings as a factor significantly related to metastatic recurrence. In conclusion, HCCs with an irregular defect during Kupffer-phase CEUS are characterized by more frequent microscopic vascular invasion and intrahepatic metastasis and are significantly associated with metastatic recurrence after resection.