Roles of EUS and IDUS in biliary diseases

Abstract

EUS and IDUS play important roles in diagnosis and treatment of biliary diseases. As for diagnosis, EUS and IDUS are useful for detecting the tumor lesion. They are also useful for evaluation of tumor depth into biliary wall, staging, intraductal spread of the tumor, lymph node swelling around the tumor, and invasion to portal vein or hepatic artery. Recently, many studies for usefulness of EUS-FNA have been reported in cases with biliary stricture which are hard to diagnose using ERCP associated biopsy or cytology. EUS and IDUS are useful for diagnosis in the case with a pancreatobiliary maljunction or small bile duct stones. As for treatment, many studies for EUS guided biliary drainage (EUS-BD) have been reported in inoperable cases with malignant biliary obstruction that are hard to treat by ERCP associated methods. Technically, EUS-BD includes rendezvous techniques, EUS-guided choledochoduodenostomy, EUS-guided hepaticogastrostomy and EUS-guided transmural cholecystostomy. At present, these methods represent an alternative to percutaneous transhepatic biliary drainage for cases with malignant biliary obstruction when endoscopic biliary drainage has failed. EUS-BD should be performed in high volume centers with extensive experiences in EUS and ERCP associated procedures. In the future, further prospective studies will be needed to establish standard methods and strategies of EUS-BD.