Catheter probe extraductal EUS reliably detects distal common bile duct abnormalities

Background. This prospective study evaluated whether extraductal catheter probe EUS as an adjunct to endoscopic retrograde cholangiography can detect or rule out choledocholithiasis and other pathologic conditions of the distal common bile duct. Methods: A total of 119 patients referred because of suspected choledocholithiasis or other bile flow obstruction for endoscopic retrograde cholangiography and papillotomy were included in this prospective study. Extraductal EUS of the distal common bile duct with a radial-scanning catheter probe was followed immediately by endoscopic retrograde cholangiography and papillotomy by a second examiner who was blinded to the EUS findings. Extraductal EUS and endoscopic retrograde cholangiography findings were compared. Results: Extraductal EUS detected 33/34 bile duct stones and all papillary adenomas (16 patients). In 8/34 patients, stones were missed on cholangiography but were seen after papillotomy and stone extraction. Extraductal EUS missed 10 peripheral lesions, one pancreatic tumor, and two distal bile duct stenoses. Overall, the sensitivity of EDUS was 78% and specificity was 98%. Conclusions: Extraductal EUS accurately detects abnormalities involving the distal common bile duct, especially small stones. The use of catheter probe EUS imaging during interventional endoscopy can help to avoid unnecessary papillotomy and can influence therapeutic strategy.