Diagnosis of common bile duct calculi with intraductal ultrasonography during endoscopic biliary cannulation

Background: Choledocholithiasis can be difficult to diagnose, even with direct cholangiography. We examined the role of biliary intraductal ultrasonography in detecting common bile duct stones that had been overlooked during endoscopic retrograde cholangiopancreatography. Methods: Eighty consecutive patients who underwent endoscopic retrograde cholangiography for suspected choledocholithiasis with negative results were evaluated with intraductal ultrasonography (20 MHz) for the presence of biliary concrements. The diagnostic criterion for stones was a strong-echo structure with acoustic shadowing. Materials of low amplitude echoes without acoustic shadowing were considered sludge. Results: Intrabile duct scanning was successful in all patients. Of the 80 patients, 20 (25%) had ultrasonic evidence of common bile duct stones. The stones measured 5 mm or less on ultrasound and their presence was confirmed macroscopically during endoscopic (17 patients) or laparoscopic (three patients) bile duct clearance. Another 37 patients (46%) had biliary sludge alone and have been followed up uneventfully. Conclusions: Biliary intraductal ultrasonography may become a useful adjunct to establish the diagnosis of occult bile duct concrements and a guide to appropriate therapeutic selection during endoscopic biliary cannulation.