Ultrasonographic Diagnosis of Anomalous Arrangement of the Pancreaticobiliary Ductal System without Dilatation of the Common Bile Duct

Abstract

The ultrasonographic diagnosis of anomalous arrangement of the pancreaticobiliary ductal system without dilatation of the common bile duct was investigated in 18 patients who were selected from among 38 patients with such an abnormal confluence. The remaining 20 patients were excluded because of complication of the gallbladder carcinoma. In 9 of 12 patients who could be examined in detail, the gallbladder wall was visualized as a two-or three-layered structure and the innermost layer was found to be thickened and irregular. Histopathological examination of resected tissue of the gallbladder suggested that these findings most probably represented mucosal hyperplasia. Considering the absence of such characteristic changes in 20 control patients without the pancreaticobiliary anastomotic anomaly, it appears that efficiency in US diagnosis of anomalous arrangement of the pancreaticobiliary ductal system without dilatation of the common bile duct can be increased if evaluations in screening tests are made with these specific changes in mind. Endoscopic ultrasonographic images were more distinct than US images; much the same findings were obtained by EUS as by US in 9 of 11 patients, and the confluence of the pancreatic and bile duct was confirmed in 7 of 11 patients. Accordingly, if such characteristic changes as were revealed by US in this study are found, then the EUS study is warranted. If there is a reasonable suspicion that the patient has an abnormal confluence, as suggested by the changes in the gallbladder wall, endoscopic retrograde cholangiopancreatography (ERCP) should be performed to make a definitive diagnosis.