Magnetic Resonance Cholangiopancreatography (MRCP) in a District General Hospital Poster No.: C-1790 Congress: ECR 2012 Type: Authors: Scientific Exhibit J. A. Maguire 1, H. Kasem 2, M. Akhtar 2, M. Strauss 2 ; 1 Glasgow/UK, 2 Wishaw/UK Keywords: Biliary Tract / Gallbladder, MR, Cholangiography, Calcifications / Calculi DOI: 10.1594/ecr2012/C-1790 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. www.myesr.org Page 1 of 12
Purpose Magnetic Resonance Cholangiopancreatography (MRCP) has long superseded Endoscopic Retrograde Cholangiopancreatography (ERCP), the latter not infrequently resulting in complications, and, hence, nowadays typically reserved for those patients with contra-indications to MRI or in whom intervention is likely to be required 1. While intra-operative cholangiograms, if preferred by the operator, may be performed at the time of laparoscopic cholecystectomy to exclude imapacted gallstones 2,3, MRCP is non-invasive and may demonstrate pathology other than impacted gallstones. Thus, the demand for the ever so popular MRCP can outstrip the availability of scan time, with MRCP representing ~10% of all MRI scans performed locally and the majority being for inpatients, putting pressure on already limited resources. The aim of this audit was to assess the correlation of liver function tests (LFT's) and ultrasound reports (USS) with MRCP findings with a view to developing a local protocol for use of MRCP for patients with clinically suspected biliary disease. Images for this section: Page 2 of 12
Fig. 1: USS demonstrating multiple small gallstones (red arrows) in a contracted gallbladder with posterior acoustic shadowing (white arrow) Page 3 of 12
Fig. 2: USS demonstrating distended CBD Page 4 of 12
Fig. 3: MRCP demonstrating small gallstones (red arrows) in an undilated CBD (black arrow); white asterisk = duodenum; black asterisk = normal gallbladder; Page 5 of 12
Fig. 4: MRCP demonstrating distended CBD / bile ducts (red arrows), but no gallstones =? stricture; white asterisk = head of pancreas; black asterisk = normal gallbladder; Page 6 of 12
Fig. 5: ERCP for stent insertion, demonstrating impacted obstructing gallstones (red arrows); black arrow = duodenoscope; white arrow = guide wire; stent not yet inserted Page 7 of 12
Methods and Materials Retrospective analysis of MRCP findings (n=100, 4 of these excluded as no ultrasound scan performed; 4 month period, 2010;Wishaw General Hospital, Lanarkshire) for patients with known or suspected biliary pathology (note histories provided on the request cards varying from e.g. "known gallstones with acutely deranged LFT's, elevated Amylase and raised inflammatory parameters" to "upper abdominal pain and nausea". Abnormal LFT's was defined as: Bilirubin> 21mg/Dl, Alkaline Phosphatase (AlP) > 135iu/l, Alanine Aminotransferase (ALT) > 50iu/l. Abnormal USS was defined as: gall-bladder wall thickening, stone(s) in gallbladder and/or dilatation of the common or intrahepatic bile duct(s)(cbd). Abnormal MRCP was defined as: stone or stricture within the CBD. A total of 96 MRCP's were reviewed and findings correlated with LFT's and USS findings. Results Analysis of subsets of abnormal LFT's (Bilirubin vs AlP vs ALT) did not correlate with abnormal imaging findings, possibly due to a small sample size. 61 of 96 patients had a normal MRCP. 1 of 15 patients with normal LFT's and USS had an abnormal MRCP. 28 of 47 patients with abnormal LFT'sand USS had a normal MRCP. Table 1: Liver Function Tests (LFT's) Normal MRCP Abnormal MRCP Normal LFT's (n=26) 21 (81%) 5 (19%) Abnormal LFT's (n=70) 40 (57%) 30 (43%) Page 8 of 12
Table 2: Ultrasound Scans (USS) Normal MRCP Abnormal MRCP Normal USS (n=38) 26 (68%) 12 (32%) Abnormal USS (n=58) 35 (60%) 23 (40%) Table 3: Liver Function Tests (LFT's) & Ultrasound Scans(USS) Normal LFT's & Normal USS (n=15) Normal LFT's & Abnormal USS (n=11) Abnormal LFT's & Normal USS (n=23) Abnormal LFT's & Abnormal USS (n=47) Normal MRCP Abnormal MRCP 14 (93%) 1 (7%) 7 (64%) 4 (36%) 12 (52%) 11 (48%) 28 (60%) 19 (40%) Images for this section: Page 9 of 12
Fig. 6: Normal LFT's & Normal USS Fig. 7: Abnormal LFT's & Abnormal USS Page 10 of 12
Conclusion In a time of NHS hardship and ever growing imaging demands, potentially resulting in unacceptable delay of urgent and non-urgent investigations and failed waiting time targets, the most efficient use of resources is mandatory. Our audit suggests local "over-use" of MRCP for investigation of patients with "nonspecific" upper abdominal pain with or without associated nausea, normal USS and LFT's. While normal USS and LFT's can, of course, not exclude relevant biliary pathology (i.e. non-obstructive impacted CBD stones), we feel that a significant number of patients with normal USS and LFT's are unlikely to require an MRCP as a first line investigation, as the probability of CBD stones is very low 4,5. We would therefore like to suggest to limit the use of MRCP in our hospital for this patient cohort to patients with a second (or more) presentation(s) with similar symptoms / signs and / or where alternative relevant diagnoses have been excluded 6. Future analysis of abnormal LFT's subsets with larger numbers may contribute to identify in - or out-patients requiring MRCP / not requiring MRCP. In summary, the key points generated following this audit are as follows: 1. Normal LFT's and USS are likely to predict a normal MRCP examination. 2. MRCP may occasionally demonstrate non-obstructive impacted CBD calculi in patients with normal LFT's and USS. 3. Although abnormal LFT's and USS are good predictors for CBD stones or strictures, normal MRCP's do not exclude preceding or current biliary pathology (e.g. sphincter of Oddi pathology; passed biliary stone; resolved cholecystitis; malignant stricture etc.). 4. Analysis of subsets of LFT's did not allow correlation with imaging findings in our patient cohort (? larger sample size needed). 5. If preferred by the operator, intra-operative cholangiogram during laparoscopic cholecystectomy can be used as an alternative to MRCP for biliary imaging. Page 11 of 12
References 1. Guidelines on the management of common bile duct stones (CBDS). E J Williams, J Green, I Beckingham, R Parks, D Martin, M Lombard.Gut 2008;57:1004-1021 2. Exploration of the common bile duct-the relevance of the clinical picture and the importance of peroperative cholangiography. Cranley B, Logan H. Br J Surg1980;67:869-72 3. Management of common bile duct stones: a ten-year experience at a tertiary care center. Lacitignola S, Minardi M. JSLS 2008;12:62-5 4. Value of ultrasound and liver function testsin determining the need for endoscopic retrograde cholangiopancreatography in unexplained abdominal pain. Thornton JR, Lobo AJ, Lintott DJ, et al. Gut 1992;33:1559-61 5. Useful predictors of bile duct stones inpatients undergoing laparoscopic cholecystectomy. Barkun AN, Barkun JS, Fried GM, et al McGill Gallstone Treatment Group. Ann Surg 1994;220:32-9 6. PWE-094 Patient selection for magnetic resonance cholangiopancreatography in management of common bile duct stones. D M L Tse 1, P Trivedi 2, I Al-Bakir 3, H D'Costa 1. 1 Department of Radiology, Oxford Radcliffe Hospitals, Banbury, UK. 2 Department of Gastroenterology, Oxford Radcliffe Hospitals, Banbury, UK. 3 Department of Surgery, Oxford Radcliffe Hospitals, Banbury, UK. Gut 2010;59:A122; doi:10.1136/ gut.2009.2090071 Personal Information Page 12 of 12