Assessing spontaneous passage of prophylactic pancreatic duct stents by X-ray: is a radiology report adequate?

Abstract

Background: Pancreatic duct stents are frequently placed for prophylaxis of post-endoscopic retrograde cholangiopancreatography pancreatitis. Because of concern for possible secondary ductal changes from a retained stent, these stents need to be monitored and removed if retained. Usually an abdominal X-ray is performed to assess retained stent, and if present, an esophagogastroduodenoscopy is performed to remove the stent. Limited data is published on false-negative radiology reports for spontaneous passage of stents.

Methods: Using an Institutional Review Board-approved stent log, a retrospective chart review of all pancreatic duct stents placed at our institution from 2008 to 2014 was performed.

Results: A total of 856 pancreatic duct stents were placed during the study period. Of these, 435 (50.8%) were prophylactic stents and 421 (49.2%) were therapeutic. Complete follow-up data were available in 426 (97.9%) patients with prophylactic stents. Six patients (1.4%) were lost to follow up and three (0.7%) expired prior to removal. In all, 283 (66%) had follow-up imaging, with 167 (39.2%) having the official radiology read with no retained pancreatic duct stent in place. Eight of these cases were "false-negative" radiology interpretation (4.8% of cases read as "no stent," NNH = 20). The stent was found either by review of image by an endoscopist or incidental stent discovery during a follow-up procedure.

Conclusion: Radiologist interpretation of abdominal X-rays to assess spontaneous passage of prophylactic pancreatic ducts stents resulted in a false-negative interpretation in approximately 5% of cases. Independent review of the images by the endoscopist may be beneficial given unfamiliarity of these stents by radiologists.

Keywords: false negative; pancreatic stent; post-endoscopic retrograde cholangiopancreatography pancreatitis.

Conflict of interest statement

Conflict of interest statement: The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Figures

Figure 1.

Inclusion criteria for prophylactic PD stenting in our cohort.

Figure 2.

Example of a false-negative reading in which the PD stent was later identified by an endoscopist reviewing the abdominal X-ray. (a) KUB and (b) inverted image with official read saying, “No retained stent.” (c) Highlight of retained stent.

Figure 3.

Evidence of an inaccurately reported “passed” stent that was later found and retrieved upon incidental endoscopy. (a) KUB with official read “no retained pancreatic stent,” (b) highlighted stent, and (c) endoscopic image of retained stent when pulled.