Conventional ultrasound (US) is the first-line imaging investigation for biliary diseases. However, it is lack of the ability to depict the microcirculation of some lesions which may lead to failure in diagnosis for some biliary diseases. The use of contrast-enhanced US (CEUS) has reached the field of
bile duct disease in recent years and promising results have been achieved. In this review, the methodology, image interpretation, enhancement pattern, clinical usefulness, and indications for CEUS in the biliary system are summarized. CEUS may be indicated in the biliary system under the following circumstances: (1) Where there is a need to make a characterization of
intrahepatic cholangiocarcinoma (ICC); (2) For differentiation diagnosis between ICC and other
tumors (i.e.
hepatocellular carcinoma or liver
metastasis) or
infectious diseases; (3) For differentiation diagnosis between biliary
cystadenoma and biliary
cystadenocarcinoma; (4) To detect malignant change in
Caroli's disease; (5) To depict the extent of
Klatskin's tumor with greater clarity; (6) To make a distinction between gallbladder
cholesterol polyp,
adenoma and polypoid
cancer; (7) To make a distinction between chronic
cholecystitis with thickened wall and
gallbladder cancer; (8) For differentiation diagnosis between motionless sludge and
gallbladder cancer; (9) For differentiation diagnosis between common bile duct
cancer and sludge or stone without acoustic shadowing; and (10) In patients who are suspected of having a drop of their percutaneous transhepatic cholangiodrainage tube, US
contrast agent can be administered to through the tube detect the site of the tube.