A case of hepatocellular carcinoma treated by radiofrequency ablation confirming the adjacent major bile duct under hybrid contrast mode through a biliary drainage catheter.

Bile duct injury is a potential complication of radiofrequency ablation (RFA). Bipolar RFA devices have recently become available. Because visibility of the bipolar RFA electrodes is not good on ultrasonography, more careful usage of the electrodes to avoid bile ducts is needed. We present a case with hepatocellular carcinoma (HCC) located near the B5 intrahepatic bile duct. To view the bile duct, we used contrast medium for ultrasonography, administered through a biliary drainage catheter for endoscopic nasobiliary drainage (ENBD). Infusing the contrast medium allowed clear visualization of the HCC adjacent to the major bile duct during RFA. We also used a navigation system for bipolar RFA to confirm positions of the electrodes and HCC. We confirmed complete ablation of the HCC while avoiding bile duct injury and late bile duct stenosis. Administration of contrast medium for ultrasonography through an ENBD tube appears useful to avoid bile duct injury during RFA.