PurposeThere are risks of common bile duct (CBD) stones in acute cholecystitis, and there is a move among surgeons to identify choledocholithiasis before surgery. Magnetic resonance cholangiopancreaticography (MRCP) has the potential to accurately detect choledocholithiasis in patients with acute cholecystitis. The aim of this study was to evaluate the predictive values of MRCP and elevated biochemical predictors for choledocholithiasis in patients with acute cholecystitis.MethodsBetween September 2006 and August 2008, of 84 patients with acute cholecystitis based on the diagnosis criteria of the Tokyo guidelines, 57 had MRCP preoperatively. The predictive values of six biochemical predictors for choledocholithiasis were also evaluated.ResultsOf the 57 patients, seven (12.28%) had choledocholithiasis, of whom three had CBD stones in nondilated ducts. The smallest stone detected in a dilated CBD and nondilated duct was 3.19 and 4.55 mm in diameter, respectively. None of our patients whose MRCP showed a clear CBD returned with symptomatic choledocholithiasis during the follow-up period. All biochemical predictors and CBD diameter had limited positive predictive values.ConclusionsMagnetic resonance cholangiopancreaticography is a reliable evaluation technique for the detection of choledocholithiasis. It reduces the misdiagnosis of retained choledocholithiasis with normal biochemical predictors and prevents the risk of overlooking choledocholithiasis. No single predictor or combined markers have been found to be reliable for including/excluding the presence of choledocholithiasis.