Role of secretin-enhanced magnetic resonance cholangiopancreatography in the evaluation of patients following pancreatojejunostomy

Functional, biological, and radiological evaluation of the pancreaticojejunal anastomosis 1 year after pancreatoduodenectomy: a prospective study

PURPOSE

This prospective study aimed to analyze the functional, biological, and radiological aspects of the pancreatic anastomosis 1 year after pancreatoduodenectomy (PD).

METHODS

From 2016 to 2019, patients with PD indication were screened. Questionnaires about pancreas insufficiency, fecal elastase tests, and magnetic resonance imaging (MRI) were performed before and 1 year after PD.

RESULTS

Twenty patients were prospectively included. The only difference between pre- and postoperative questionnaires was constipation (less frequent 1 year after PD). Median pre- and postoperative fecal elastase levels were 96 μg/g (IQR 15-196, normal value > 200) and 15 μg/g (IQR 15-26, p = 0.042). There were no significant differences in terms of main pancreatic duct (MPD) size (4, IQR 3-5 vs. 4 mm, IQR 3-5, p = 0.892), border regularity, stenosis, visibility, image improvement, and secondary pancreatic duct dilation before and after secretin injection. All patients but one (2 refused and 2 were lost to follow-up, 15/16, 94%) had a patent pancreaticojejunal anastomosis on 1-year MRI.

CONCLUSION

Although median 1-year fecal elastase was significantly lower than preoperatively, suggesting that exocrine secretion was altered, the anatomical outcome as assessed by MRI was excellent showing high patency rate (15/16, 94%) at 1 year. This emphasizes the difference between anatomy and function.

Jejunal response to secretin is independent of the pancreatic response in secretin-enhanced magnetic resonance cholangiopancreatography

PURPOSE

To investigate whether jejunal secretions are independent of the pancreatic response to secretin in secretin-enhanced Magnetic Resonance Cholangiopancreatography (s-MRCP) examination of subjects with and without chronic pancreatitis (CP).

METHODS

Patients were identified through a search of s-MRCP examinations performed between 2014-2016 (n = 513) as well as the multidisciplinary pancreatitis clinic registry (n = 586). Fifty cases with CP (based on M-ANNHEIM criteria) and 50 matched controls were selected. Signal intensity changes after secretin administration (˜1-5 min' post-secretin response) in three locations were assessed: second portion of the duodenum (D2), third/fourth portions of the duodenum (D3-4), and the jejunum. The post-secretin response was compared between (cases vs. controls) and within the study groups.

RESULTS

There was a significantly lower 1-5 min' post-secretin response among CP patients in D2 (all p-values <0.01). However, no significant difference in 1-5 min' post-secretin response was detected in the jejunum. Minute-by-minute analysis of the post-secretin response showed a significant increase up to the 5th minute only in D2 of the control group. The post-secretin response in the jejunum was significant after 1 min but was similar among patients with CP and controls. CP was a significant determinant of post-secretin response in D2 but not in the jejunum.

CONCLUSIONS

Early post-secretin response at jejunum is independent of the pancreatic response that can be detected at D2, and should not be misinterpreted as a rapid pancreatic response. Therefore, pancreatic function on s-MRCP should be assessed by the presence of fluid in D2 and not jejunum.

The clinical value of secretin-enhanced MRCP in the functional and morphological assessment of pancreatic diseases

Secretin-enhanced magnetic resonance cholangiopancreatography (S-MRCP) provides a non-invasive way, with which, to evaluate pancreatic duct (PD) anatomy and exocrine pancreatic function. S-MRCP can be added to the routine pancreas MR examination in equivocal cases. Moreover, it can detect subtle PD involvement, allowing diagnosis of early, rather than end-stage, pancreatic diseases. Although S-MRCP is a valuable non-invasive diagnostic method, it is only performed in a few centres due to relative high cost. Furthermore, less familiarity with its indications, the examination technique, and image interpretation also contribute to its limited use. Thus, the purpose of this article is to explain secretin's mechanism of action, the examination technique, the clinically relevant indications, the advantages, and limitations. Finally, we will focus on image analysis and its role in achieving an early and accurate diagnosis of specific pancreatic and PD diseases.

Endoscopic characteristics and usefulness of endoscopic dilatation of anastomotic stricture following pancreaticojejunostomy: case series and a review of the literature

The incidence of pancreatitis induced by anastomotic stricture following pancreaticodigestive tract anastomosis as a late-onset adverse event has been reported to be 3% or lower, but some cases repeatedly relapse and are difficult to treat. Endoscopic identification and treatment of the anastomotic site are considered to be difficult, and only a small number of cases have been reported. We present three cases with recurrent pancreatitis induced by anastomotic stricture following pancreaticojejunostomy applied after pancreaticoduodenectomy. We successfully identified the anastomotic site and performed endoscopic dilatation of the anastomotic stricture, and pancreatitis has not recurred. We characterized endoscopic features of the anastomotic site, understanding of which is essential to identify the site, and investigated useful techniques to identify the site and perform cannulation for pancreatography. Furthermore, we showed the safety and usefulness of endoscopic dilatation for anastomotic stricture following pancreaticojejunostomy according to our three cases and a review of the literature.

Secretin-stimulated MR cholangiopancreatography: spectrum of findings in pancreatic diseases

Abstract

MR cholangiopancreatography (MRCP) is an imaging technique that has evolved over the past 2 decades and that continues to have a fundamental role in the non-invasive detection of morphologic features of the pancreatic ducts. In several studies, MRCP has shown a good correlation with endoscopic retrograde cholangiopancreatography in the evaluation of diseases and anatomic variants of the pancreatic ductal system. However, in physiologic conditions the pancreatic ducts are not always easily recognisable. More recently, secretin-enhanced MRCP protocols have been developed for a more complete assessment of pancreatic ducts and glandular function, including monitoring of pancreatic flow dynamics and duodenal filling after pancreatic hormonal stimulation with secretin. The injection of this hormone causes temporary dilation of the pancreatic ducts, principally by increasing pancreatic exocrine secretions, and thus improving MRCP detection of the ducts and characterisation of pancreatic disorders and allowing the assessment of the exocrine pancreatic reserve. The purpose of this pictorial review is to summarise the technical aspects of secretin-stimulated MRCP, to report the secretin-stimulated MRCP findings of pancreatic duct abnormalities and to review the diagnostic capabilities of secretin-stimulated MRCP in various pancreatic ductal system conditions.

Main Messages

• MRCP has a fundamental role in the non-invasive detection of pancreatic ducts.

• In physiologic conditions pancreatic ducts are not always well detected on MRCP.

• Secretin injection causes temporary dilation of pancreatic ducts and thus improves MRCP detection.

• Secretin-stimulated MRCP may allow the assessment of the exocrine pancreatic reserve.

• Secretin increases the diagnostic capabilities of MRCP for evaluating pancreatic disorders.

Secretin-Stimulated Magnetic Resonance Imaging Assessment of the Benign Pancreatic Disorders: Systematic Review and Proposal for a Standardized Protocol

This systemic review summarizes the current literature and general consensus on secretin-stimulated magnetic resonance imaging (s-MRI) of the benign pancreatic disorders and discusses important aspects on how s-MRI is optimally performed. The aim is to provide an overview, for clinicians and radiologist, of the s-MRI protocols and the range of clinical applications. Furthermore, the review will summarize the criteria for evaluation of pancreatic morphology and function based on s-MRI.The literature search indentified 69 original articles and 15 reviews. Chronic pancreatitis was the disease that was most frequently assessed by s-MRI (33%), followed by acute pancreatitis (9%). Dynamic thick-slab 2-dimensional magnetic resonance cholangiopancreatography was the most used imaging sequence (86%). The diameter of the main pancreatic duct (75%) and pancreatic exocrine function based on visual grading of duodenal filling (67%) were the most evaluated pancreatic features. Sufficient similarities between studies were identified to propose the most agreeable standardized s-MRI protocol for morphological and functional assessment of the pancreas. In the future, more research and increased collaboration between centers is necessary to achieve more consensus and optimization of s-MRI protocols.

Magnetic resonance imaging of the postoperative pancreas

Magnetic resonance imaging (MRI) with magnetic resonance cholangiopancreatography provides the comprehensive evaluation of patients following pancreatic surgery regarding parenchymal pancreatic changes, ductal abnormalities, evaluation of anastomoses, and detection of tumor recurrence. Normal and pathologic MRI presentations in patients who underwent pancreatic surgery are reviewed. The MRI/magnetic resonance cholangiopancreatography techniques used in the patients after pancreatic surgery are presented, and a concise review of the current array of pancreatic surgical procedures is provided.