To investigate the clinical value of magnetic resonance cholangiopancreatography (MRCP) in the preoperative evaluation of patients with biliary calculus.

Clinical data of 70 patients with biliary calculus in Sun Yat-sen Memorial Hospital and the Third Affiliated Hospital of Sun Yat-sen University from June 2012 to June 2013 were retrospectively analyzed. There were 38 males and 32 females with age ranging from 18 to 87 years old and the median age of 52 years old. The informed consents of all patients were obtained and the ethical committee approval was received. The patients underwent ultrasound examination and MRCP before operation. The surgical procedures were cholecystectomy + bile duct exploration and the intraoperative exploration result was the gold standard of diagnosis for biliary calculus and biliary tract variations. The detectable rate of biliary calculus and biliary tract variations by two methods were compared using Chi-square test and Fisher's exact probability test.

The detectable rate of gallstones was 93% (62/67) by ultrasound and was 79% (53/67) by MRCP, where significant difference was observed (χ²=4.968, P<0.05). The detectable rate of common bile duct stones was 61% (17/28) by ultrasound and was 86% (24/28) by MRCP, where significant difference was observed (χ²=4.462, P<0.05). The detectable rate of the left and right hepatic duct stones was 2/5 by ultrasound and was 4/5 by MRCP, where no significant difference was observed (P>0.05). The detectable rate of intrahepatic bile duct stones was 36% (4/11) by ultrasound and was 73% (8/11) by MRCP, where no significant difference was observed (P>0.05). The detectable rate of biliary tract variations was 2/8 by ultrasound and was 7/8 by MRCP, where significant difference was observed (P<0.05).

MRCP is superior to ultrasound examination in the detection of common bile duct stones and biliary tract variations. It can be a common practice in the preoperative evaluation of patients with biliary calculus when circumstances allow.