The value of magnetic resonance cholangiopancreatography in predicting common bile duct stones in patients with gallstone disease.
BACKGROUND: The application of available predictive scoring systems for the detection of common bile duct (CBD) stones has not reduced the number of patients who undergo unnecessary endoscopic retrograde cholangiopancreatography. The aim of this study was to create a predictive model for CBD stones and to assess the value of magnetic resonance cholangiopancreatography (MRCP) in prediction. METHODS: In 1998, 366 patients with gallstone disease (118 males, 248 females; mean age 57 (range 8-84) years) underwent cholecystectomy. Statistical analysis was performed on patient data obtained at the time of first presentation. RESULTS: CBD stones were demonstrated in 43 (12 per cent) of 366 patients. The predictive model for common duct stones included ultrasonography showing CBD stones or bile duct dilatation, age greater than 60 years, fever, serum alkaline phosphatase level above 670 units/l and serum amylase level above 95 units/l. In patients with a predicted probability greater than 5 per cent, CBD stones were present in 11 per cent, compared with 1 per cent in patients with a probability of 5 per cent or less. MRCP had an observed sensitivity of 95 per cent, specificity of 100 per cent, positive predictive value of 100 per cent and negative predictive value of 98 per cent. CONCLUSION: In patients with a predicted probability for CBD stones of more than 5 per cent, MRCP is recommended in order to confirm the presence or absence of stones and as guidance in further management.