Background: Endoscopic ultrasonography (EUS) appears to be the best imaging method for the diagnosis of choledocholithiasis. The aim of this preliminary, prospective, controlled study was to assess the accuracy of EUS and magnetic resonance cholangiopancreatography (MRCP) in the diagnosis of common bile duct stones.
Methods: From December 1995 through April 1997, all patients referred because of suspicion of the presence of common bile duct stones were included in the study. EUS and MRCP were performed. Each examination was performed by a different operator unaware of the result of the other procedure. The definitive diagnosis was established by means of endoscopic retrograde cholangiography with sphincterotomy or a surgical procedure.
Results: Forty-three patients (18 men, 25 women) with a mean age of 60.9 +/- 14.5 years (range 25 to 81 years) were included in the study. Eleven patients were excluded because of unavailability of magnetic resonance imaging(n = 5) or EUS (n = 6). Ten patients (31.2%) had choledocholithiasis. For this diagnosis, the sensitivity of EUS was 100%, the specificity was 95.4%, the positive predictive value was 90.9%, and the negative predictive value was 100%. The corresponding values for MRCP were 100%, 72.7%, 62.5%, and 100%, not significantly different from EUS results. The accuracy of EUS was 96.9%, and that of MRCP was 82.2%.
Conclusion: This preliminary study confirmed EUS as an accurate and noninvasive procedure for the diagnosis of common bile duct stones. MRCP, which had a high sensitivity and high negative predictive value, might be an accurate technique for patients with a contraindication to EUS.