Abstract
The clinical significances of ultrasound-related procedures for biliary tract diseases are detection of lesions, differential diagnosis, tumor staging and therapeutic applications. Transabdominal ultrasonography, which can evaluate the gallbladder wall and the intra/extra hepatic bile duct, is widely accepted as a noninvasive modality for diagnosis of abdominal diseases. The distal bile duct and the ampulla of Vater cannot be generally estimated by this method. EUS is useful for diagnosis of biliary diseases. The tumor staging for biliary cancer can be determined by the correlation between the tumor echo and the structure of the wall or the surrounding organs. EUS can detect a small stone in the gallbladder or the bile duct without the artifact from air in the GI tract. Furthermore, EUS is also useful for detection of small lesions, differential diagnosis, tumor staging for biliary cancer such as gallbladder cancer, cholangiocarcinoma, and ampullary cancer. In cases of difficult differential diagnosis, EUS-FNA has been reported to provide useful information. Further studies including new methods, e.g. enhanced ultrasonography, are warranted for improvement of diagnosis for biliary diseases.
