Magnetic resonance cholangiopancreatography accurately detects common bile duct stones in resolving gallstone pancreatitis.

Background: There is controversy about the optimal method to detect common bile duct (CBD) stones in patients with mild resolving gallstone pancreatitis. The aim of this study was to evaluate magnetic resonance cholangiopancreatography (MRCP) in detecting choledocholithiasis in this group of patients.
Study Design: A prospective randomized trial was conducted. Patients randomized to group 1 (n = 34) underwent laparoscopic cholecystectomy (LC) and intraoperative cholangiography (IOC). Those randomized to group 2 (n = 29) had preoperative MRCP, of these, patients with negative MRCP underwent LC and IOC, patients with positive MRCP had preoperative ERCP followed by LC.
Results: Sixty-three patients were randomized (34 to group 1 and 29 to group 2). CBD stones were found in 5 patients in group 1. CBD exploration was performed in 2 patients, preoperative ERCP in 1, and postoperative ERCP in the other 2. MRCP showed CBD stones in 4 patients in group 2. There were two false-positive MRCPs. Four patients with a negative MRCP did not have IOC or ERCP, the remaining 21 patients with a negative MRCP had a negative IOC. The MRCP sensitivity was 100% (95% CI, 16-100%), specificity 91% (95% CI, 72-99%), positive predictive value 50% (95% CI, 7-93%), negative predictive value 100% (95% CI, 84-100%), and accuracy 92% (95% CI, 74-99%).
Conclusions: Patients with resolving gallstone pancreatitis and a negative MRCP do not need preoperative ERCP or IOC. Only patients with a positive MRCP will require preoperative ERCP.