Prospective study of endoscopic ultrasound performance in suspected choledocholithiasis

Background: The close proximity of the echoendoscope to the extrahepatic bile ductal system and its safety make endoscopic ultrasonography (EUS) an excellent method for examining the common bile duct (CBD). The aim of the present study was to compare EUS diagnostic performance for CBD stones with endoscopic retrograde cholangiography (ERC). Methods: Aprospective series of our first 60 patients (65% women, average age 43 years) who were referred for ERC for suspicion of choledocholithiasis based on clinical, biochemical and cross-sectional imaging ( ultrasonography [ US] or computed tomography [CT]) data underwent radial EUS. EUS results were recorded as positive or negative for CBD stones before starting the ERC. All patients underwent ERC with a balloon sweep of the bile duct as the standard of reference for CBD stone. All procedures were performed during the same endoscopy session by a single endoscopist who was blinded to the clinical, biochemical and imaging data. Results: Sixty-five percent of our patients had low to moderate risk for CBD stones. EUS diagnoses were confirmed by ERC as follows: 23 true positive, 33 true negative, three false negative and one false positive ( sensitivity of 89%, specificity of 97%, positive predictive value of 96%, and negative predictive value of 92%; overall accuracy of 93%). Compared to the EUS diagnostic accuracy ( 90%) during the first 30 cases, EUS had a very high diagnostic accuracy ( 97%) for CBD stones during the last 30 cases (P = 0.31). Conclusion: EUS is highly accurate for the diagnosis of choledocholithiasis. The EUS learning curve is relatively short for CBD stones.