Value of magnetic resonance cholangiography in the preoperative diagnosis of common bile duct stones.

OBJECTIVE: The aim of this study was to assess the performance of magnetic resonance cholangiography (MRC) in the preoperative diagnosis of choledocholithiasis. METHODS: A total of 147 consecutive patients underwent MRC for clinical and biological signs of common bile duct stones. ERCP was then carried out in 101 patients in whom there was a past history of cholecystectomy. The remaining 46 patients without a past history of biliary surgery underwent cholecystectomy and intraoperative cholangiography (IOC). The diagnosis obtained by MRC was compared with the final diagnosis established after endoscopic or surgical removal of calculi. RESULTS: A total of 113 patients had choledocholithiasis (single or multiple, including 15 cases of microlithiasis). There were no false-positive results with MRC. The false-negative results were caused mainly by small stones <3 mm in diameter, and to a lesser extent, cholangitis. Overall, the sensitivity was 93% and the specificity 100% for MRC in detecting common bile duct stones. The sensitivity and specificity of ERCP were respectively 94% and 100%, versus 93.5% and 93.3% for IOC. There was no statistically significant difference, however, between MRC and the other techniques. CONCLUSION: MRC is a key technique in the preoperative diagnosis of choledocholithiasis. Its diagnostic value is comparable to ERCP, but it appears to be more specific than IOC. Nevertheless, its diagnostic capability remains limited in cases of microlithiasis and cholangitis.