Endoscopic ultrasound in the evaluation of radiologic abnormalities of the liver and biliary tree.

Gastroenterologists increasingly find themselves in the un-enviable position of having to choose the optimal radiographic test to visualize the biliary tree and the liver. This dilemma is compounded by the rapid evolution of the available technologies and their ever-increasing resolution capabilities. Endoscopic ultrasound (EUS) has shown itself to be equally capable of providing detailed imaging of the biliary tree and of surrounding structures; its potential for evaluating liver lesions is just now being realized. EUS-fine needle aspiration (FNA) may supplant some of the existing technologies as it offers a way to sample masses, strictures, lymph nodes, and now certain segments of the liver and periportal regions. This review takes an in-depth look at the role of EUS in evaluating bile duct dilatation, suspected choledocholithiasis, biliary strictures, and polyps and masses of the gallbladder. It also reviews the literature on the exciting and rapidly evolving role of EUS-FNA evaluation of occult, metastatic, and primary hepato-cellular malignancies, as well as periportal lesions. Technologies such as EUS elastography may completely obviate FNA of liver lesions.