Carcinoma of the ampulla of Vater: sonographic and CT diagnosis.

Twenty patients with carcinoma of the ampulla of Vater were studied with sonography (N = 9) or both sonography and CT (N = 11). The tumor was shown by sonography in 16 patients (80%) as a small, round or oval, fairly well delineated mass in between the dilated distal common bile duct and duodenum which was delineated owing to luminal fluid or gas (N = 13); or as a polypoid mass within the dilated distal common bile duct resulting in abrupt obstruction (N = 3). In the remaining four patients, the mass was not delineated. Bile ducts were dilated down to the level of mass or ampullary region in all cases (100%), while the pancreatic duct was dilated in five cases (45%). We believe that sonography is the technique of initial choice in the diagnosis of carcinoma of the ampulla of Vater by identifying the mass at the distal end of the dilated common bile duct and/or pancreatic duct.