Diagnostic accuracy of magnetic resonance cholangiopancreatography in patients with extrahepatic cholestasis: a retrospective cohort study

Abstract

Background/Aims: Differential diagnosis of extrahepatic cholestasis can be challenging due to variable sensitivity and specificity rates of imaging techniques. Magnetic resonance cholangiopancreatography (MRCP) is a non-invasive method used for evaluation of biliary tree. We aimed to investigate diagnostic accuracy of MRCP in biliary obstruction. 
 Materials and Methods: Medical records of patients admitted with extrahepatic cholestasis between January 2012 and December 2016 were retrospectively reviewed. Patients who had endoscopic retrograde cholangiopancreatography (ERCP) following MRCP were included. Demographic and clinical characteristics of patients were noted. Final diagnosis of ERCP was accepted as gold standard. Diagnostic efficiency of MRCP was evaluated by calculating sensitivity, specificity, accuracy, negative and positive predictive values as compared with ERCP.
 Results: There were 615 patients with a mean age of 60.1±17.5 years. Using MRCP, choledocholithiasis, malignant and benign strictures were diagnosed in 337 (54.8%), 101 (16.4%), and 39 patients (6.3%), respectively. Normal MRCP findings were present in 65 patients (10.6%). Final diagnoses via ERCP were as follows: choledocholithiasis (n=390, 63.4%), malignant stricture (n=152, 24.7%), benign stricture (n=62, 10.1%), and normal findings (n=11, 1.8%). Sensitivity and specificity of MRCP were 70.8% and 72.9% for choledocholithiasis, 55.9% and 96.5% for malign stricture, and 16.1% and 94.8% for benign stricture, respectively. Overall accuracy rates were 71.5%, 86.5%, and 86.8% for choledocholithiasis, malign and benign strictures, respectively.
 Conclusion: Diagnostic accuracy of MRCP is variable for different biliary/cholestatic etiologies. Due to a lower sensitivity for choledocholithiasis, normal MRCP findings should be handled with caution, especially when there is a clinical suspicion for biliary obstruction. 
 Keywords: extrahepatic cholestasis, magnetic resonance cholangiopancreatography, endoscopic retrograde cholangiopancreatography, sensitivity, specificity.