title: The relative roles of magnetic resonance cholangiopancreatography (MRCP) and endoscopic ultrasound in diagnosis of common bile duct calculi: a critically appraised topic.
abstract: BACKGROUND
  The relative roles of magnetic resonance cholangiopancreatography (MRCP) and endoscopic ultrasound (EUS) in the investigation of common bile duct (CD) calculi were evaluated using "evidence-based practice" (EBP) methods.
  
  
  METHODS
  A focused clinical question was constructed. A structured search of primary and secondary evidence was performed. Retrieved studies were appraised for validity, strength and level of evidence (Oxford/CEBM scale: 1-5). Retrieved literature was divided into group A; MRCP slice thickness >or=5 mm, group B; MRCP slice thickness = 3 mm or 3D-MRCP sequences.
  
  
  RESULTS
  Six studies were eligible for inclusion (3 = level 1b, 3 = level 3b). Group A: sensitivity and specificity of MRCP and EUS were (40%, 96%) and (80%, 95%), respectively. Group B: sensitivity and specificity of MRCP and EUS were (87%, 95%) and (90%, 99%), respectively.
  
  
  CONCLUSIONS
  MRCP should be the first-line investigation for CD calculi and EUS should be performed when MRCP is negative in patients with moderate or high pre-test probability.
authors.affiliation: Department of Radiology, St. Vincent's University Hospital, Dublin 4, Ireland. colmjmcmahon@yahoo.co.uk
authors.forename: Colm J
authors.initials: CJ
authors.lastname: McMahon
mesh_terms: D049448:Cholangiopancreatography, Magnetic Resonance; D042883:Choledocholithiasis / Q000175:diagnosis*; D019160:Endosonography; D019317:Evidence-Based Medicine; D006801:Humans; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity