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Endoscopy 2001; 33(11): 930-939
DOI: 10.1055/s-2001-17924
DDW Reports 2001
© Georg Thieme Verlag Stuttgart · New York

ERCP Topics

P. Connor, R. H. Hawes
  • Digestive Disease Center, Medical University of South Carolina, Charleston, South Carolina, USA
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Publication Date:
18 October 2001 (online)

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Pancreaticobiliary Imaging

Endoscopic retrograde cholangiopancreatography (ERCP) remains the gold standard for pancreaticobiliary ductal imaging. Over the last few years, the quality of imaging produced by magnetic resonance cholangiopancreatography (MRCP) has improved greatly, and indeed in some specialist centers it has supplanted ERCP as a diagnostic test. However, there is still confusion regarding the place of MRCP in the investigational algorithm of patients with suspected pancreaticobiliary disease-whether or not it avoids the need for ERCPs, and if so, whether it is cost-effective in doing so.

In two abstracts, Hellerhoff and colleagues in Munich [1] [2] report investigations on the impact of MRCP on the number of ERCPs performed and on whether MRCP aided those ERCPs that required intervention. A total of 113 patients with a “moderate” probability of pancreaticobiliary disease (bilirubin ≤ 2.4 mg/dl and common bile duct diameter ≤ 10 mm) underwent MRCP prior to diagnostic ERCP. The results were disappointing. Although MRCP was relatively accurate in identifying strictures, stones, and normal ducts (sensitivity 77 % for stones, 83 % for normal ducts), the results were inferior to published data [3] [4] [5] . MRCP had a sensitivity and specificity of 97 % and 100 % in 34 patients with normal pancreatic ducts, and a sensitivity and specificity of 100 % and 100 % in 11 patients with main pancreatic duct strictures. As all of the patients went on to undergo ERCP, the data presented are essentially a comparison between ERCP and MRCP. The overall conclusion was that MRCP rarely makes it possible to avoid ERCP in patients with a “moderate” probability of pathology. Although the small numbers of patients in the subgroups should be borne in mind, this study is in conflict with other published work, and suggests that MRCP is not yet ready to relieve ERCP of its role in the diagnosis of pancreaticobiliary diseases. Subsequently, the authors attempted to assess the value of MRCP prior to interventional ERCP. In 45 patients with obstructive jaundice or chronic pancreatitis, information obtained from MRCP was used in the planning of the subsequent intervention. The extent of hilar strictures (eight patients), the number and size of “difficult” common bile duct (CBD) stones (three patients), the extent of bilio-enteric anastomotic strictures (nine patients), and the presence of strictures or stones in the main pancreatic duct (MPD) in patients with known chronic pancreatitis (25 patients) were evaluated. Again, apart from the chronic pancreatitis group, the subgroup numbers were too small to judge the importance of the results. Also, it was not clear whether this was a retrospective or a prospective study-a fact that tempers the authors’ conclusion that MRCP can play a significant role in the planning of therapeutic ERCP. The information may well have been nice to have, but what difference did it ultimately make?

An interesting abstract by a group in Nagoya, Japan [6] introduces a further imaging modality that may be of value in the assessment of pancreatic disease. Three-dimensional transabdominal ultrasonography uses a combination of standard ultrasonography, electromagnetic sensors, and computer software reconstruction to produce three-dimensional images of intra-abdominal structures. In 34 patients, it was found that adequate “virtual” images were obtained in 30 patients when the results were compared with the resected specimens, direct pancreatoscopy, or direct cholangioscopy. The authors’ conclusion that virtual pancreatoscopy can produce adequate three-dimensional images of the main pancreatic duct, common bile duct, and pancreatic cysts, is qualified only by their acknowledgment that further hardware and software improvements are needed before accurate definition of the shape and extent of pancreatic tumors is possible. Problems with the technique are likely to be encountered due to the limitations of extracorporeal ultrasound in imaging the entire pancreas. One wonders whether it might be possible to apply principles from this technique to EUS. The cost and often limited availability of MRCP are its major disadvantages, and-provided that the cost differential is significant-this study suggests a method of achieving noninvasive pancreaticobiliary imaging at an acceptable price.

References

P . Connor, M.B.Ch. B., M.R.C.P.I.

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