title: Utility of MRCP in clinical decision making of suspected choledocholithiasis: An institutional analysis and literature review.
abstract: BACKGROUND
  The ideal treatment algorithm for suspected choledocholithiasis is not yet well defined. Imaging options include magnetic resonance cholangiopancreatography (MRCP), endoscopic retrograde cholangiopancreatography (ERCP), and intraoperative cholangiogram (IOC). MRCP is diagnostic, while the other two modalities can also be therapeutic. Each of these modalities for diagnosis and treatment carries its own set of risks, benefits, and institutional costs. We hypothesized that there would be a significant difference between the biochemical profiles and characteristics of patients who undergo ERCP vs. MRCP vs. operative intervention as the initial choice of treatment/imaging modality.
  
  
  METHODS
  We performed a retrospective review of the electronic medical records for all patients with a coded diagnosis of choledocholithiasis from 2011 to 2014. The initial diagnostic modality was assessed for each hospital encounter. The statistical characteristics of MRCP as compared to fluoroscopic imaging of the biliary tree (ERCP, IOC) were analyzed.
  
  
  RESULTS
  Overall, 527 hospital encounters were identified. Initial intervention included ERCP in 63%, MRCP in 12%, and cholecystectomy in 25% of patients. Patients undergoing cholecystectomy first, compared to MRCP or ERCP, tended to have lower values for alkaline phosphatase (P < 0.001) and AST (P = 0.002) as well as be of younger age (P < 0.0001). Of the patients that underwent MRCP as their initial procedure, 82% subsequently underwent either ERCP or laparoscopic cholecystectomy. In patients who underwent an initial MRCP followed by either ERCP or IOC, the predictive performance of MRCP was as follows: sensitivity = 0.90, specificity = 0.86, positive predictive value = 0.97, negative predictive value = 0.60, agreement (Cohen's Kappa) = 0.64.
  
  
  CONCLUSIONS
  There is a significant difference in the laboratory evaluation and demographics of patients undergoing ERCP, MRCP, and laparoscopic cholecystectomy. MRCP was followed with a more invasive test a majority of the time. Since MRCP did not change the management of patients with suspected choledocholithiasis, its utility in this patient population should be questioned. Further research is needed to better define the pretest characteristics which would predict which patients do not need further intervention after MRCP as well as defining the most cost-effective strategy.
authors.affiliation: Department of Medical Education, Gundersen Medical Foundation, La Crosse, WI, USA.
authors.forename: Wesley R
authors.initials: WR
authors.lastname: Badger
authors.affiliation: Department of Research, Gundersen Medical Foundation, La Crosse, WI, USA.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Borgert
authors.affiliation: Department of Research, Gundersen Medical Foundation, La Crosse, WI, USA.
authors.forename: Kara J
authors.initials: KJ
authors.lastname: Kallies
authors.affiliation: Department of General Surgery, Gundersen Health System, La Crosse, WI, USA. Electronic address: snkothar@gundersenhealth.org.
authors.forename: Shanu N
authors.initials: SN
authors.lastname: Kothari
mesh_terms: D000368:Aged; D002758:Cholangiography; D002760:Cholangiopancreatography, Endoscopic Retrograde; D049448:Cholangiopancreatography, Magnetic Resonance; D002763:Cholecystectomy; D042883:Choledocholithiasis / Q000000981:diagnostic imaging* / Q000601:surgery; D000066491:Clinical Decision-Making; D005260:Female; D006801:Humans; D007430:Intraoperative Care; D008297:Male; D012189:Retrospective Studies
keywords: Biliary disease; Cholecystectomy; Choledocholithiasis; Endoscopic retrograde cholangiopancreatography; Intraoperative cholangiogram; Magnetic resonance cholangiopancreatography