Preoperative diagnosis of bile duct strictures - Comparison of intraductalultrasonography with conventional endosonography

Background: The accuracy of intraductal ultrasonography (IDUS) and endoscop ic ultrasonography (EUS) were compared in diagnosing biliary obstruction an d in predicting surgical resectability. Methods: Fifty-six patients with biliary obstruction were investigated preo peratively with both conventional EUS and IDUS. The ultrasonographic minipr obe was inserted into the bile duct system through the working channel of t he duodenoscope during endoscopic retrograde cholangiopancreatography (ERCP ). Conventional endosonography was performed with echoendoscopes in a stand ard technique. Images of endoluminal ultrasonography were prospectively rev iewed and compared with intraoperative findings and resection specimen anal yses. Results: IDUS exceeded EUS in terms of accuracy (IDUS, 89.1%; EUS, 75.6%; P < 0.002), sensitivity (IDUS, 91.1%; EUS, 75.7%; P < 0.002), specificity (I DUS, 80%; EUS, 75%; NS), and T-staging (IDUS, 77.7%; EUS, 54.1%; P < 0.001) . In bile duct carcinomas the accuracy rate for lymph node staging using ID US (60%) is comparable with that using EUS (62.5%). In pancreatic carcinoma s, however, lymph node staging using IDUS (13.3%) is significantly (P < 0.0 02) inferior to EUS (69.2%). Endoluminal ultrasonography may predict the po tential resectability of bile duct tumors (IDUS, 81.8%; EUS, 75.6%; P < 0.0 02). Conclusions: IDUS proved to be accurate in preoperative diagnosing and T-st aging of malignant biliary strictures, whereas it is not suitable for lymph node staging. IDUS using miniprobes during ERCP exceeds conventional EUS i n terms of depiction of bile duct obstruction, diagnostic accuracy, and sen sitivity and in the prediction of surgical tumor resectability. Additionall y, different to EUS, IDUS can conveniently be performed during ERCP in one and the same session.