Role of magnetic resonance cholangiopancreatography for choledocholithiasis: analysis of patients with negative MRCP.

OBJECTIVE: To investigate the negative predictive value of magnetic resonance cholangiopancreatography (MRCP) for common bile duct (CBD) stones and the prognosis of patients suspected to have choledocholithiasis in whom the MRCP was negative for CBD stones.

METHODS: We enrolled the patients suspected to have choledocholithiasis in whom the MRCP was negative for the CBD stones between January 2008 and March 2011 and retrospectively analyzed the outcomes of 115 patients.

RESULTS: Endoscopic retrograde cholangiopancreatography (ERCP) was performed in 27 patients (23%, group 1), and none had CBD stones. The negative predictive value of MRCP was 100%. During a median follow-up of 18.3 months, acute cholangitis with newly developed CBD stones occurred in two patients. Eighty-eight patients (77%, group 2) did not undergo ERCP and all recovered from acute cholangitis without CBD surgery. During a median follow-up of 18.7 months, acute cholangitis, acute cholecystitis, gallstone pancreatitis, and pancreatico-biliary cancers occurred in four (4.6%), three (3.5%), one (1.2%), and three (3.5%) patients, respectively. New CBD stones were found in only two patients among four patients with recurrent acute cholangitis. No patient had recurrent cholangitis caused by MRCP-missed CBD stones. The rates of recurrent cholangitis and cholangitis-free survival did not differ between groups 1 and 2.

CONCLUSION: The negative predictive value of MRCP was very high. ERCP can be reserved for patients who are MRCP negative for choledocholithiasis, but close follow-up is needed because of recurrent cholangitis or pancreatico-biliary cancer.