Quantification of pancreatic exocrine function with secretin-enhanced magnetic resonance cholangiopancreatography: normal values and short-term effects of pancreatic duct drainage procedures in chronic pancreatitis. Initial results

Management of Pancreatic Calculi in Chronic Pancreatitis: A Review Article

Chronic pancreatitis is a slow, irreversible, and progressive inflammatory condition with abdominal pain, loss of parenchyma, fibrosis, and calculus formation. It also causes loss of exocrine and endocrine function. Gallstones and alcohol is the most frequent cause of chronic pancreatitis. It is also caused by other factors, including oxidative stress, fibrosis, and repeated incidence of acute pancreatitis. Chronic pancreatitis is followed by several sequelae, one of them being formation of calculi in the pancreas. The formation of calculi can occur in the main pancreatic duct, branches of the duct, and parenchyma. The cardinal sign of chronic pancreatitis is pain caused by obstruction of pancreatic ducts and its branches leading to ductal hypertension resulting in pain. The main aim of endotherapy includes pancreatic duct decompression. The management options vary based on the type and size of the calculus. The treatment of choice for small-sized pancreatic calculi is endoscopic retrograde cholangiopancreatography (ERCP) followed by sphincterotomy and extraction. The large-sized calculi need fragmentation before extraction, which is done by extracorporeal shock wave lithotripsy (ESWL). Surgery can be an option for patients having severe pancreatic calculi if endoscopic therapy fails. For diagnostic purposes, imaging plays a very important role. The treatment options remain complex if the radiological and laboratory findings overlap. Due to advancements in diagnostic imaging, treatment options have become precise and helpful. It can significantly lower the quality of life along with immediate and long-term problems that pose a serious risk to life. This review comprises the various management options available for removing calculi following chronic pancreatitis, including surgical, endoscopic, and medical therapy.

Chronic Pancreatitis: Epidemiology, Diagnosis, and Management Updates

Chronic pancreatitis is a clinical entity that results from the progressive inflammation and irreversible fibrosis of the pancreas resulting from the cumulative injury sustained by the pancreas over time. It is an illness with variable presentations that can severely impact quality of life, while its long-term complications such as exocrine pancreatic insufficiency (EPI), diabetes mellitus, and risk of pancreatic cancer can become life threatening. The diagnosis of chronic pancreatitis can be challenging as despite the recent advancements in imaging technology, the radiographic findings do not become prominent until late stages of disease. Thus, the physicians' clinical acumen in obtaining thorough history taking focusing on risk factors, clinical symptoms, in addition to high-quality imaging, often guide to the accurate diagnosis of chronic pancreatitis. Endoscopy also plays a pivotal role in the diagnosis and management of chronic pancreatitis. Endoscopic ultrasound (EUS) is believed to be the most sensitive modality for diagnosing chronic pancreatitis. Despite efforts, however, natural history studies have demonstrated that 61% of individuals with chronic pancreatitis will require at least one endoscopic intervention, while 31% will require a surgical procedure as part of their management strategy. Recent advancements in genomic studies have furthered our understanding of the genetic polymorphisms that are associated with the pathogenesis of chronic pancreatitis. Genetic testing offers the potential to reveal treatable pancreatitis-related disorders, and can inform decision making with regard to radical therapies for persistent or severe disease such as total pancreatectomy with islet autotransplantation (TPIAT). The management of patients suffering from chronic pancreatitis often requires a multi-disciplinary approach, addressing pertinent symptoms as well as the sequelae of chronic inflammation and fibrosis. Abdominal pain is the prevailing symptom and most common complication of chronic pancreatitis, and impairs quality of life. Although heavily dependent on a wide range of analgesia, endoscopic treatment such as endoscopic retrograde cholangiopancreatography (ERCP) and surgical intervention can offer long-lasting relief of symptoms. For EPI, treatment with pancreatic enzyme supplements offers marginal-to-moderate relief. The most feared complication of chronic pancreatitis-the development of pancreatic cancer-has no known prevention measure to date.

Secretin-Enhanced MRCP: How and Why-AJR Expert Panel Narrative Review

Secretin-enhanced MRCP (S-MRCP) has advantages over standard MRCP for imaging of the pancreaticobiliary tree. Through the use of secretin to induce fluid production from the pancreas and leveraging of fluid-sensitive MRCP sequences, S-MRCP facilitates visualization of ductal anatomy, and the findings provide insight into pancreatic function, allowing radiologists to provide additional insight into a range of pancreatic conditions. This narrative review provides detailed information on the practical implementation of S-MRCP, including patient preparation, logistics of secretin administration, and dynamic secretin-enhanced MRCP acquisition. Also discussed are radiologists' interpretation and reporting of S-MRCP examinations, including assessments of dynamic compliance of the main pancreatic duct and of duodenal fluid volume. Established indications for S-MRCP include pancreas divisum, anomalous pancreaticobiliary junction, Santorinicele, Wirsungocele, chronic pancreatitis, main pancreatic duct stenosis, and assessment of complex postoperative anatomy. Equivocal or controversial indications are also described along with an approach to such indications. These indications include acute and recurrent acute pancreatitis, pancreatic exocrine function, sphincter of Oddi dysfunction, and pancreatic neoplasms.

Optimum imaging of chronic pancreatitis

Chronic pancreatitis is an inflammatory process of the pancreas characterized by progressive parenchyma destruction, resulting in pain and exocrine and endocrine insufficiency. In the advanced stages the diagnosis by imaging is usually straightforward, while in the early phases of the disease there can be a paucity of findings at imaging, thus making an early diagnosis challenging. Different imaging modalities can have a role in the initial diagnosis and in the longitudinal follow-up of patients affected by chronic pancreatitis, also enabling to assess the complications of the disease. Radiography, Ultrasonography, CT and MRI can all provide morphological information, and MRI with the administration of secretin can also provide functional information. The use of an appropriate technique is fundamental for optimizing the examination to the clinical question.

ACG Clinical Guideline: Chronic Pancreatitis

Chronic pancreatitis (CP) is historically defined as an irreversible inflammatory condition of the pancreas leading to varying degrees of exocrine and endocrine dysfunction. Recently however, the paradigm for the diagnosis has changed in that it breaks with the traditional clinicopathologic-based definition of disease, focusing instead on diagnosing the underlying pathologic process early in the disease course and managing the syndrome more holistically to change the natural course of disease and minimize adverse disease effects. Currently, the most accepted mechanistically derived definition of CP is a pathologic fibroinflammatory syndrome of the pancreas in individuals with genetic, environmental, and/or other risk factors who develop persistent pathologic responses to parenchymal injury or stress. The most common symptom of CP is abdominal pain, with other symptoms such as exocrine pancreatic insufficiency and diabetes developing at highly variable rates. CP is most commonly caused by toxins such as alcohol or tobacco use, genetic polymorphisms, and recurrent attacks of acute pancreatitis, although no history of acute pancreatitis is seen in many patients. Diagnosis is made usually on cross-sectional imaging, with modalities such as endoscopic ultrasonography and pancreatic function tests playing a secondary role. Total pancreatectomy represents the only known cure for CP, although difficulty in patient selection and the complications inherent to this intervention make it usually an unattractive option. This guideline will provide an evidence-based practical approach to the diagnosis and management of CP for the general gastroenterologist.

Quantitative pancreatic MRI: a pathology-based review

MRI plays an important role in the clinical management of pancreatic disorders and interpretation is reliant on qualitative assessment of anatomy. Conventional sequences capturing pancreatic structure can however be adapted to yield quantitative measures which provide more diagnostic information, with a view to increasing diagnostic accuracy, improving patient stratification, providing robust non-invasive outcome measures for therapeutic trials and ultimately personalizing patient care. In this review, we evaluate the use of established techniques such as secretin-enhanced MR cholangiopancreatography, diffusion-weighted imaging, T ₁, T ₂* and fat fraction mapping, but also more experimental methods such as MR elastography and arterial spin labelling, and their application to the assessment of diffuse pancreatic disease (including chronic, acute and autoimmune pancreatitis/IgG4 disease, metabolic disease and iron deposition disorders) and cystic/solid focal pancreatic masses. Finally, we explore some of the broader challenges to their implementation and future directions in this promising area.

Impaired Exocrine Pancreatic Function Associates With Changes in Intestinal Microbiota Composition and Diversity

BACKGROUND & AIMS

Changes in intestinal microbiome composition are associated with inflammatory, metabolic, and malignant disorders. We studied how exocrine pancreatic function affects intestinal microbiota.

METHODS

We performed 16S ribosomal RNA gene sequencing analysis of stool samples from 1795 volunteers from the population-based Study of Health in Pomerania who had no history of pancreatic disease. We also measured fecal pancreatic elastase by enzyme-linked immunosorbent assay and performed quantitative imaging of secretin-stimulated pancreatic fluid secretion. Associations of exocrine pancreatic function with microbial diversity or individual genera were calculated by permutational analysis of variance or linear regression, respectively.

RESULTS

Differences in pancreatic elastase levels associated with significantly (P < .0001) greater changes in microbiota diversity than with participant age, body mass index, sex, smoking, alcohol consumption, or dietary factors. Significant changes in the abundance of 30 taxa, such as an increase in Prevotella (q < .0001) and a decrease of Bacteroides (q < .0001), indicated a shift from a type-1 to a type-2 enterotype. Changes in pancreatic fluid secretion alone were also associated with changes in microbial diversity (P = .0002), although to a lesser degree.

CONCLUSIONS

In an analysis of fecal samples from 1795 volunteers, pancreatic acinar cell, rather than duct cell, function is presently the single most significant host factor to be associated with changes in intestinal microbiota composition.

Pancreatic Insufficiency: What Is the Gold Standard?

Endoscopic pancreatic function testing assesses exocrine insufficiency and chronic pancreatitis. Indirect pancreatic function tests have limited sensitivity and specificity in early disease stages. Magnetic resonance cholangiopancreatography shows promise in detecting early changes as a direct measure of pancreatic function. This article summarizes the evolution of pancreatic function testing and highlights areas for future research, such as development of diagnostic biomarkers to stratify disease severity and targeted therapies to retard disease progression.

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.

A study of the clinical utility of a 20-minute secretin-stimulated endoscopic pancreas function test and performance according to clinical variables

BACKGROUND AND AIMS

Direct pancreas juice testing of bicarbonate, lipase, or trypsin after stimulation by secretin or cholecystokinin is used to determine exocrine function, a surrogate for diagnosing chronic pancreatitis (CP). Endoscopic pancreas function tests (ePFTs), where a peak bicarbonate concentration (PBC) ≥80 mEq/L in pancreas juice is considered normal, are now used more frequently. In this ePFT, aspirates start 35 minutes after secretin administration because pancreas output peaks 30 minutes after secretagogue administration. The performance of ePFT in a cohort of patients with a presumptive diagnosis of CP referred to a pancreas clinic for consideration of an intervention including total pancreatectomy and islet autotransplantation was studied, compared with EUS, ERCP, histology, and consensus diagnosis. The effect of sedation, narcotic use, aspirate volume, body mass index, age, and proton pump inhibitors (PPIs) on test performance is reported.

METHODS

After a test dose, synthetic human secretin was administered intravenously, and 30 minutes later sedation was achieved with midazolam and fentanyl or propofol. A gastroscope was advanced to the major papilla where 4 continuous aspiration samples were performed at 5-minute intervals in sealed bottles. PBC ≥80 mEq/L was normal.

RESULTS

Eighty-one patients had ePFTs from August 2010 through October 2015. Twenty-seven patients (33%) were diagnosed with CP. Eighteen of the 27 patients with CP and 1 of the 54 patients without CP had an abnormal ePFT, producing a sensitivity of 66% (95% CI, 46.0-83.5), specificity 98% (95% CI, 90.1-99.9), positive predictive value 94.7% (95% CI, 74-99.9), and negative predictive value 85.5% (95% CI, 74.2-93.1). ERCP and PBC concordance was generally poor, but none of the patients without CP had major EUS changes, and only 3 patients with a PBC <80 mEq/L had a normal EUS. The PBC was affected by narcotics and PPI use.

CONCLUSION

A 20-minute ePFT after secretin administration had a marginal sensitivity for diagnosis of CP. The diagnosis of CP should not rely on a single study and certainly not a PFT. The duodenal aspirate volume did not correlate with the PBC, which contrasts with current secretin-enhanced MRCP knowledge; therefore, further studies on this subject are warranted. Neither type of sedation, BMI, nor age affected test performance. Narcotics and PPIs may affect the PBC, so borderline results should be interpreted with caution in these groups.

Secretin-stimulated MRI assessment of exocrine pancreatic function in patients with cystic fibrosis and healthy controls

PURPOSE

Secretin-stimulated magnetic resonance imaging (s-MRI) and pancreatic diffusion weighted imaging (DWI) are novel non-invasive imaging techniques for assessment of exocrine pancreatic insufficiency (EPI). The aim was to validate s-MRI assessed pancreatic secreted volume using novel semi-automatic quantification software, and to assess the ability of s-MRI with DWI to diagnose EPI in patients with cystic fibrosis (CF).

METHODS

s-MRI and DWI was performed in 19 patients with CF (median age 21 years; range 16-56; eight men) and in 10 healthy controls (HC) (median age 46 years; range 20-65; four men). Sequential coronal T2-weighted images covering the duodenum and small bowel and axial DWI were acquired before and 1, 5, 9, and 13 min after secretin stimulation. A short endoscopic secretin test was used as reference method for EPI.

RESULTS

CF patients with EPI had lower apparent diffusion coefficient before secretin in the pancreatic head (P < 0.001) and lower secreted bowel fluid volumes (P = 0.035) compared to HC and CF patients without EPI. ROC curve analyses identified that secreted fluid volume after 13 min yielded the highest diagnostic accuracy for diagnosing EPI (AUC 0.93; 95% CI [0.80-1.00]).

CONCLUSION

Pancreatic s-MRI is useful for the assessment of exocrine pancreatic function with high diagnostic accuracy for the diagnosis of EPI in CF.

Detection of exocrine dysfunction by MRI in patients with early chronic pancreatitis

PURPOSE

To determine if T1-weighted MR signal of the pancreas can be used to detect early CP.

METHODS

A retrospective analysis was performed on 51 suspected CP patients, who had both secretin-enhanced magnetic resonance cholangiopancreatography (S-MRCP) and an intraductal secretin stimulation test (IDST). There were 29 patients in normal and 22 patients in the low bicarbonate group. Bicarbonate level, total pancreatic juice volume, and excretory flow rate were recorded during IDST. Signal intensity ratio of pancreas (SIR), fat signal fraction, pancreatograms findings, and grade of duodenal filling were recorded on S-MRCP by two blinded radiologists.

RESULTS

There was a significant difference in the signal intensity ratio of the pancreas to spleen (SIR_p/s) between the normal and low bicarbonate groups (p < 0.0001). A significant positive correlation was found between pancreatic fluid bicarbonate level and SIR_p/s (p < 0.0001). SIR_p/s of 1.2 yielded sensitivity of 77% and specificity of 83% for detection of pancreatic exocrine dysfunction (AUC: 0.89).

CONCLUSION

T1-weighted MR signal of the pancreas has a high sensitivity and specificity for the detection of parenchymal abnormalities related to exocrine dysfunction and can therefore be helpful in evaluation of suspected early CP.

Imaging in pancreatic disease

Pancreatic diseases, chronic pancreatitis, pancreatic cancer and diabetes mellitus, taken together, occur in >10% of the world population. Pancreatic diseases, as with other diseases, benefit from early intervention and appropriate diagnosis. Although imaging technologies have given clinicians an unprecedented toolbox to aid in clinical decision-making, advances in these technologies and development of molecular-based diagnostic tools could enable physicians to identify diseases at an even earlier stage and, thereby, improve patient outcomes. In this Review, we discuss and identify gaps in the use of imaging techniques for the early detection and appropriate treatment stratification of various pancreatic diseases, including diabetes mellitus, acute and chronic pancreatitis and pancreatic cancer. Imaging techniques discussed are MRI, CT, PET and ultrasonography. Additionally, the identification of new molecular targets for imaging and the development of contrast agents that are able to give molecular information in noninvasive radionuclear imaging and ultrasonography are emerging areas of innovation that could lead to increased diagnostic accuracy and improved patient outcomes.

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.

Diagnostic accuracy of secretin-stimulated ultrasonography of the pancreas assessing exocrine pancreatic failure in cystic fibrosis and chronic pancreatitis

OBJECTIVE

Volume output failure is a feature of decreasing exocrine pancreatic function. This parameter is assessed by secretin-stimulated MRI in several studies. Our purpose was to evaluate ultrasonography of the fluid in the descending duodenum and Wirsung duct (WD) after secretin stimulation as a measure of pancreatic fluid flow in patients expected to have severe output failure.

MATERIAL AND METHODS

We included subjects with chronic pancreatitis (CP), cystic fibrosis (CF) and a group of healthy controls in a prospective observation study. Transabdominal ultrasonography was performed before and during 15 min after secretin i.v. duodenal juice was collected by endoscopic short test (EST), and bicarbonate concentration measured. Patient groups were classified according to exocrine pancreatic function.

RESULTS

Pancreatic insufficient CF (CFI) patients and CP insufficient (CPI) patients showed less duodenal fluid filling compared to other groups (p < 0.001). Measures of the WD diameter could only identify the most severe failure in the CFI group (p < 0.001).

CONCLUSION

Secretin-stimulated ultrasonography can be used to assess pancreatic fluid flow and may be combined with EST in the evaluation of exocrine pancreatic function. Fluid filling in the descending part of duodenum was the most accurate predictor of pancreatic insufficiency in both patient groups. The test demonstrated better diagnostic accuracy diagnosing exocrine pancreatic failure in the CF patients than in CP patients.

Anatomic variants of the pancreatic duct and their clinical relevance: an MR-guided study in the general population

OBJECTIVES

To investigate the frequency of pancreatic duct (PD) variants and their effect on pancreatic exocrine function in a population-based study using non-invasive secretin-stimulated magnetic resonance cholangiopancreatography (sMRCP).

METHODS

Nine hundred and ninety-five volunteers, 457 women and 538 men, aged 51.9 ± 13.4 years, underwent navigator-triggered, T2-weighted, 3D turbo spin echo MRCP on a 1.5 T system after 1 unit/kg secretin administration. Two readers evaluated images for PD variants. Pancreatic exocrine function and morphological signs of chronic pancreatitis such as abnormalities of the main PD, side branch dilatation, and pancreatic cysts were evaluated and related to PD variants using a Kruskal-Wallis test and post hoc analysis.

RESULTS

Of all sMRCP, 93.2% were of diagnostic quality. Interobserver reliability for detection of PD variants was found to be kappa 0.752 (95 %CI, 0.733 - 0.771). Normal PD variants were observed in 90.4% (n = 838/927). Variants of pancreas divisum was identified in 9.6% (n = 89/927). Abnormalities of the main PD, side branch dilatation, and pancreatic cysts were observed in 2.4%, 16.6%, and 27.7%, respectively, and were not significantly different between pancreas divisum and non-divisum group (P = 0.122; P = 0.152; P = 0.741). There was no association between PD variants and pancreatic exocrine function (P = 0.367).

CONCLUSION

PD variants including pancreas divisum are not associated with morphological signs of chronic pancreatitis or restriction of pancreatic exocrine function.

KEY POINTS

MRCP allows the evaluation of pancreatic duct variants and morphological change. Pancreatic duct variants are not associated with morphological signs of chronic pancreatitis. Pancreas divisum is not accompanied by restriction of pancreatic exocrine function. Pancreatic duct variants including pancreas divisum are limited in their clinical relevance.

Direct visualization of pancreatic juice flow using unenhanced MRI with spin labeling can be aid in diagnosing chronic pancreatitis

OBJECTIVE

The purpose of this study is to prospectively assess whether direct visualization of pancreatic juice flow using an unenhanced MRI technique with spin labeling can aid in the diagnosis of chronic pancreatitis.

SUBJECTS AND METHODS

Ten healthy volunteers and 50 patients who were categorized as having no chronic pancreatitis (n = 11), early chronic pancreatitis (n = 7), or established chronic pancreatitis (n = 32) underwent MRI, including direct pancreatic juice visualization using a flow-out technique with a time-spatial labeling inversion pulse, comprising a nonselective inversion recovery pulse immediately followed by a spatially selective inversion labeling pulse. The mean velocities and volumes of pancreatic juice excretion were also obtained. Variance tests were used to evaluate the clinical groups with respect to the appearance rate and mean velocity; the Kruskal-Wallis test was used for volume.

RESULTS

There were no significant differences between healthy volunteers and patients with no chronic pancreatitis. The appearance rate, mean velocity, and volume of pancreatic juice excretion tended to decrease with the degree of chronic pancreatitis. Although the difference in these values was statistically significant between the healthy group and the established chronic pancreatitis group, the values of the early group and other groups were not statistically significant. There was a significant correlation between the appearance rate of pancreatic juice and the clinical groups (τ = -0.4376, p = 0.0015).

CONCLUSION

The measurement of directly visualized pancreatic juice flow may aid in establishing the diagnosis of chronic pancreatitis.

Endoscopic treatment of pancreatic calculi

Chronic pancreatitis is a progressive inflammatory disease that destroys pancreatic parenchyma and alters ductal stricture, leading to ductal destruction and abdominal pain. Pancreatic duct stones (PDSs) are a common complication of chronic pancreatitis that requires treatment to relieve abdominal pain and improve pancreas function. Endoscopic therapy, extracorporeal shock wave lithotripsy (ESWL), and surgery are treatment modalities of PDSs, although lingering controversies have hindered a consensus recommendation. Many comparative studies have reported that surgery is the superior treatment because of reduced duration and frequency of hospitalization, cost, pain relief, and reintervention, while endoscopic therapy is effective and less invasive but cannot be used in all patients. Surgery is the treatment of choice when endoscopic therapy has failed, malignancy is suspected, or duodenal stricture is present. However, in patients with the appropriate indications or at high-risk for surgery, endoscopic therapy in combination with ESWL can be considered a first-line treatment. We expect that the development of advanced endoscopic techniques and equipment will expand the role of endoscopic treatment in PDS removal.

MR imaging of the pancreas

Magnetic resonance (MR) imaging of the pancreas is useful as both a problem-solving tool and an initial imaging examination of choice. With newer imaging sequences such as diffusion-weighted imaging, MR offers improved ability to detect and characterize lesions and identify and stage tumors and inflammation. MR cholangiopancreatography can be used to visualize the pancreatic and biliary ductal system. In this article, the use of MR to evaluate the pancreas, including recent advances, is reviewed and the normal appearance of the pancreas on different imaging sequences, as well as inflammatory diseases, congenital abnormalities, and neoplasms of the pancreas, are discussed.

Secretin-stimulated MRCP in volunteers: assessment of safety, duct visualization, and pancreatic exocrine function

OBJECTIVE

The objective of our study was to investigate secretin-stimulated MRCP in terms of the safety of secretin, improvement of duct visualization, and assessment of pancreatic exocrine function.

MATERIALS AND METHODS

Eight hundred sixteen volunteers (370 women and 446 men; mean age, 49.7 ± 13.1 [SD] years) underwent 3D MRCP before and after secretin stimulation (1 U/kg of body weight) at 1.5 T. For the first 2 hours after secretin injection, subjects were evaluated for adverse reactions. Improvement of duct visualization after secretin stimulation was subjectively evaluated by two readers and was quantified by duct diameter measurements. Pancreatic exocrine function was evaluated subjectively by two readers according to the duodenal filling and was quantified using calibrated volumetric measurements of total excreted volume and pancreatic flow output.

RESULTS

Two subjects (0.2%) showed flushing (minor adverse reaction). Duct visualization after secretin injection was improved for reader 1 in 468 (57.4%) and for reader 2 in 478 (58.6%) subjects, was unchanged for reader 1 in 324 (39.7%) and for reader 2 in 315 (38.6%) subjects, and was worse for reader 1 in 24 (2.9%) and reader 2 in 23 (2.8%) subjects (interrater agreement, κ = 0.925). Main pancreatic duct diameters increased significantly after secretin stimulation: pancreatic head, 10.5% (mean); body, 12.5%; and tail, 7.7%. Pancreatic exocrine function evaluated according to assessment of duodenal filling was as follows: grade 0 (restricted function) in 0.7% of subjects by both readers, grade 1 (reduced function) in 4.8% of subjects by reader 1 and 4.5% of subjects by reader 2, grade 2 (low-grade reduced function) in 31.1% of subjects by reader 1 and 26.5% of subjects by reader 2, and grade 3 (physiologic function) in 63.4% of subjects by reader 1 and 68.3% of subjects by reader 2 (interrater agreement, κ = 0.838). The mean total excreted volume was 111.8 ± 49.8 (SD) mL, and the mean pancreatic flow output was 9.6 ± 4.2 mL/min.

CONCLUSION

Secretin-stimulated MRCP moderately improves main pancreatic duct visualization and allows noninvasive quantification of pancreatic exocrine function with a negligible risk of side effects.

Quantification of pancreatic exocrine function of chronic pancreatitis with secretin-enhanced MRCP

AIM: To obtain reference values for pancreatic flow output rate (PFR) and peak time (PT) in healthy volunteers and chronic pancreatitis (CP); to correlate quantification of secretin enhanced magnetic resonance cholangiopancreatography (SMRCP) of pancreatic fluid output following secretin with fecal elastase-1 (FE-1) tests.

METHODS: The present study includes 53 subjects comprised of 17 healthy individuals and 36 patients with CP from April 2011 to January 2013. The 36 patients with CP were divided into three groups of mild CP (n = 14), moderate CP (n = 19) and advanced CP (n = 3) by M-ANNHEIM classification for CP.. Fifty-three cases underwent FE-1 test and magnetic resonance imaging using 3.0 T-device (Signa EXCITE, GE Healthcare). Coronal T₂-weighted single-shot turbo spin-echo, spiratory triggered, covering the papillae, duodenum and small bowel. MRCP was performed with a heavily T₂-weighted fat-suppressed long TE HASTE sequence (thick slab 2D MRCP sequence), repeated every 2 min up to 11 min after 0.1 mL/kg secretin injection (Secrelux, Sanochemia^®, Germany). FE-1 test used sandwich enzyme-linked immunosorbent assay (ELISA) test (ScheBo. Tech^®, Germany).

RESULTS: A good linear correlation showed between the calculated volume and the actual volume by Phantom experiments. Fifty-three paired Quantification of secretin enhanced magnetic resonance cholangiopancreatography (MRCPQ) and FE-1 data sets were analyzed. The mean FE-1 of 53 cases was 525.41 ± 94.44 μg/g for 17 healthy volunteers, 464.95 ± 136.13 μg/g for mild CP, 301.55 ± 181.55 μg/g for moderate CP, 229.30 ± 146.60 μg/g for advanced CP. Also, there was statistically significant difference in FE-1 (P = 0.0001) between health and CP. The mean values of PFR and PT were 8.18 ± 1.11 mL/min, 5.76 ± 1.71 min for normal; 7.27 ± 2.04 mL/min, 7.71 ± 2.55 min for mild CP; 4.98 ± 2.57 mL/min, 9.10 ± 3.00 min for moderate CP; 4.13 ± 1.83 mL/min, 12.33 ± 1.55 min for advanced CP. Further, statistically significant difference in PFR (P = 0.0001) and PT (P = 0.0001) was observed between health and CP. Besides, there was correlation (r = 0.79) and consistency (K = 0.6) between MRCPQ and ELISA Test. It was related between M-ANNHEIM classification and PFR (r = 0.55), FE-1 (r = 0.57).

CONCLUSION: SMRCP can provide a safe, non-invasive and efficient method to evaluate the exocrine function of the pancreas.

Correlation between secretin-enhanced MRCP findings and histopathologic severity of chronic pancreatitis in a cat model

BACKGROUND/OBJECTIVES

To evaluate the usefulness of secretin-enhanced magnetic resonance cholangiopancreatography (S-MRCP) in chronic pancreatitis (CP), we compared the severity of disease determined histopathologically with that indicated by S-MRCP imaging parameters in an induced CP cat model.

MATERIALS AND METHODS

An experimental group of randomly chosen cats (n = 24) underwent ligation of the pancreatic duct to induce CP, and cats in a similarly chosen control group (n = 8) were sham-operated. MRCP was performed prior to secretin stimulation, and 5 and 15 min afterward, noting in particular the pancreatic duct caliber change (PDC) and the increasing degree of fluid volume (IDFV). Histopathological changes were observed in pancreatic samples processed for hematoxylin-eosin and Sirius red staining, and CP was classified as normal, minimal, moderate, or advanced. Correlations were investigated between these groups and the PDC at 5 min and the IDFV at 15 min.

RESULTS

Between cats with minimal CP and the controls, the differences in mean IDFV and PDC were not significant although diseased cats showed a downward trend in both parameters. However, compared with the control group both the mean IDFV and PDC were significantly lower in cats with moderate (IDFV, P = 0.001; PDC, P = 0.013) or advanced (IDFV, P = 0.013; PDC, P = 0.001) CP.

CONCLUSION

The S-MRCP parameters IDFV and PDC correlated with the histopathological severity of induced CP. S-MRCP could be used to evaluate the severity of CP, although it is somewhat insensitive for depicting very early disease.

Assessment of exocrine pancreatic function by secretin-stimulated magnetic resonance cholangiopancreaticography and diffusion-weighted imaging in healthy controls

PURPOSE

To characterize and quantify exocrine pancreatic function by secretin-stimulated magnetic resonance cholangiopancreaticography (s-MRCP) and diffusion-weighted imaging (DWI) in healthy subjects and compare these findings to morphological features, ie, pancreatic volume and secretin-stimulated peak bicarbonate concentration measured in pancreatic juice.

MATERIALS AND METHODS

Pancreatic magnetic resonance imaging (MRI) (1.5 T) was performed in 20 healthy volunteers among which 10 underwent gastroscopy with duodenal intubation. MRI included T2-weighted imaging and DWI acquired before and 1, 5, 9, and 13 minutes after secretin administration. Secreted pancreatic juice volumes were calculated based on the sequential T2-weighted images and pancreatic volumes and apparent diffusion coefficient (ADC) values were estimated.

RESULTS

The mean pancreatic secretion rate declined from 9.5 mL/min at 1-5 minutes (postsecretin) to 2.9 mL/min at 9-13 minutes. Pancreatic head ADC values significantly increased from baseline (1.29 × 10(-3) mm(2) /s) to 1 minute postsecretin (1.48 × 10(-3) mm(2) /s) (P = 0.003). Secreted pancreatic juice volume at 1 minute after secretin correlated positively with peak bicarbonate concentration (n = 10, P = 0.05).

CONCLUSION

Secretin-stimulated MRCP and DWI can characterize and quantify exocrine pancreatic function in healthy subjects. These imaging methods may prove relevant for patients with exocrine pancreatic dysfunction.

Quantitative analysis of pancreatic exocrine function in healthy adults using secretin-enhanced MRCP

AIM: To assess the value of secretin-enhanced magnetic resonance cholangiopancreatography (MRCP) and fecal elastase 1 (FE-1) tests for quantification of exocrine function in normal adults.

METHODS: From April 2011 to January 2013, 17 healthy volunteers were enrolled in the study. There were 5 females and 12 males. Their median age was 44.0 years ± 14.4 years (24-64 years), and their median BMI was 24.5 ± 13.4 (18.9-31.1). All subjects had undergone both MRCP and FE-1. Coronal T2-weighted sequences and MRCP were performed before and at a 2 min interval after administration of 0.1 mL/kg secretin. Semiquantitative s-MRCP grading for duodenal filling was used to preliminarily assess the exocrine function of the pancreas. By drawing an appropriate region of interest, changes in signal intensity in the imaging volume were plotted against time and the flow rate derived from the gradient. Pancreatic exocrine secretions were quantified by pancreatic flow output (PFR) and peak time (PT).

RESULTS: Phantom experiments showed a good correlation between known and calculated volumes of water (P < 0.001). Ten minutes after secretin administration, 17 volunteers showed a duodenal filling beyond the genu inferius (grade 3). Mean FE-1 was 353.3 μg/g ± 134.7 μg/g (range 201.55 μg/g-673.20 μg/g). Mean PFR was 8.17 mL/min ± 1.11 mL/min (range 6.2 mL/min-11 mL/min), and mean PT was 5.2 min ± 1.2 min (range 3-7 min). There is a good correlation between PFR and FE-1 (P < 0.001).

CONCLUSION: Semi-SMRCPQ can be used to preliminarily assess the exocrine function of the pancreas. SMRCP provides a safe, non-invasive, efficient method for evaluating the exocrine function of the pancreas.

MRI of the pancreas: problem solving tool

Advances in MR hardware and pulse sequence design over the years have improved the quality and robustness of MR imaging of the pancreas. Today, MRI is an indispensible tool for studying the pancreas and can provide useful information not attainable with other noninvasive or minimally invasive imaging techniques. In the present review, specific cases are reviewed where the strengths of MRI demonstrate the utility of this imaging modality as a problem solving tool.

MR imaging techniques for pancreas

Pancreatic magnetic resonance (MR) imaging has become a useful tool in evaluating pancreatic disorders. Technical innovations in MR imaging have evolved over the last decade, with most sequences being performed in one or a few breath-holds. Three-dimensional sequences with thin, contiguous slices allow for improved spatial resolution on the postgadolinium images and MR cholangiopancreatography (MRCP). The diagnostic potential of MRCP is equivalent to endoscopic retrograde pancreatography, particularly when intravenous secretin is used to enhance the pancreatic duct assessment. This article highlights the advantages and disadvantages of state-of-the-art and emerging pulse sequences and their application to imaging pancreatic diseases.

Update on endoscopic management of main pancreatic duct stones in chronic calcific pancreatitis

Pancreatic duct stones are a common complication during the natural course of chronic pancreatitis and often contribute to additional pain and pancreatitis. Abdominal pain, one of the major symptoms of chronic pancreatitis, is believed to be caused in part by obstruction of the pancreatic duct system (by stones or strictures) resulting in increasing intraductal pressure and parenchymal ischemia. Pancreatic stones can be managed by surgery, endoscopy, or extracorporeal shock wave lithotripsy. In this review, updated management of pancreatic duct stones is discussed.

Quantitative MRCP assessment of pancreatic exocrine reserve and its correlation with faecal elastase-1 in patients with chronic pancreatitis

PURPOSE

This retrospective study was done to correlate a quantitative assessment of the pancreatic exocrine reserve by dynamic secretin magnetic resonance cholangiopancreatography (MRCPQ) with the faecal elastase-1 (FE-1) test in patients with chronic pancreatitis.

MATERIALS AND METHODS

Thirty-five patients with a clinical diagnosis of chronic (CP) or acute recurrent (ARP) pancreatitis were enrolled. FE-1 was indicative of the pancreatic exocrine reserve. Subsequently, the patient population was subdivided into two groups according to a clinical threshold value of 200 μg/g. All patients underwent MRCP examination during secretin administration. Duodenal filling volume was calculated on T2-weigthed rapid acquisition with relaxation enhancement (RARE) MRCP images obtained 10 min after secretin injection. Duodenal filling volumes were compared with FE-1 values. Scatter plots, Pearson correlation coefficient and the Mann-Whitney U test were performed.

RESULTS

Thirty-five paired MRCPQ-FE1 data sets were analysed. MRCPQ was significantly different (p=0.007) between patients with impaired and preserved pancreatic function; median and interquartile range (IQR) were 150.7 ml (137.3-205.5 ml; n=9) and 332.4 ml (190.6-506.9 ml; n=26). Both Pearson correlation coefficient (p<0.001) and the Mann-Whitney U test (p=0.007) were significant.

CONCLUSIONS

MRCPQ significantly correlates with FE-1 values. It is possible to discriminate impaired and preserved pancreatic exocrine function using MRCPQ.

Endoscopic therapy in chronic pancreatitis

Chronic pancreatitis (CP) is a debilitating disease that can result in chronic abdominal pain, malnutrition, and other related complications. The main aims of treatment are to control symptoms, prevent disease progression, and correct any complications. A multidisciplinary approach involving medical, endoscopic, and surgical therapy is important. Endoscopic therapy plays a specific role in carefully selected patients as primary interventional therapy when medical measures fail or in patients who are not suitable for surgery. Endoscopic therapy is also used as a bridge to surgery or as a means to assess the potential response to pancreatic surgery. This review addresses the role of endoscopic therapy in relief of obstruction of the pancreatic duct (PD) and bile du ct, closure of PD leaks, and drainage of pseudocysts in CP. The role of endoscopic ultrasound-guided celiac plexus block for pain in chronic pancreatitis is also discussed.

State-of-the-art pancreatic MRI

OBJECTIVE

The purpose of this article is to discuss the most current techniques used for pancreatic imaging, highlighting the advantages and disadvantages of state-of-the-art and emerging pulse sequences and their application to pancreatic disease.

CONCLUSION

Given the technologic advances of the past decade, pancreatic MRI protocols have evolved. Most sequences can now be performed in one or a few breath-holds; 3D sequences with thin, contiguous slices offer improved spatial resolution; and better fat and motion suppression allow improved contrast resolution and image quality. The diagnostic potential of MRCP is now almost as good as ERCP, with pancreatic MRI as the main imaging technique to investigate biliopancreatic pain, chronic pancreatitis, and cystic pancreatic tumors at many institutions. In addition, functional information is provided with secretin-enhanced MRCP.

Magnetic resonance cholangiopancreatography reports in the evaluation of chronic pancreatitis: a need for quality improvement

BACKGROUND

Numerous publications from academic centers suggest that magnetic resonance cholangiopancreatography (MRCP) can diagnose early chronic pancreatitis (CP) and assess pancreatic secretory reserve/function. However, the rigorous composite interpretation methods and quantitative secretory dynamics reported in these studies are not routinely measured in clinical practice. Therefore, the utility of routine MRCP reports in the clinical setting is unknown.

STUDY DESIGN

Cross-sectional study of patients referred to a tertiary center who underwent both MRCP and endoscopic pancreas function testing (ePFT) for assessment of chronic pancreatitis and abdominal pain.

AIMS

To compare MRCP and sMRCP reports to a reference standard pancreas function test for diagnosis of chronic pancreatitis.

METHODS

Source population: patients seen within a pancreas clinic at a tertiary referral center. MRCP and sMRCP reports were reviewed to record pancreas duct (dilation, side-branch changes), parenchyma enhancement (T(1), T(2) signal) and physiologic response (duodenal filling, pancreas duct response) to secretin. ePFT was categorized based on previously published data (normal peak bicarbonate >80 mEq/l). Referent values were calculated for MRCP and sMRCP using secretin ePFT as gold standard.

RESULTS

A total of 69 patients were identified (mean age 43.5 +/- 12; 65.2% female). 28 (40.6%) patients had abnormal ePFT based on their peak bicarbonate level. The mean bicarbonate values in the abnormal PFT and normal PFT groups were 59 +/- 13.9 and 95.3 +/- 12.6 mEq/l, respectively. Peak bicarbonate decreased with severity of chronic pancreatitis on MRCP (p = 0.0016). There was fair agreement of MRCP and ePFT (kappa 0.335 [0.113, 0.557]). The pre-stimulation pancreas duct changes reported were found to be the only predictor of abnormal pancreas function (p = 0.002). The post-stimulation findings of duodenal filling (p = 0.47), T(2)enhancement (p = 0.21) or change in pancreas duct caliber (p = 0.3) reported did not improve MRCP agreement with ePFT. Overall diagnostic accuracy, sensitivity and specificity were 70, 85 and 46%, respectively, for MRCP reports using ePFT as the gold standard.

CONCLUSIONS

Pancreas ductal features described on routine MRCP reports correlate with abnormal pancreas function. Current MRCP reports should be standardized to include all radiologic information available in hopes of predicting early chronic pancreatitis.

Clinical feasibility of Açai (Euterpe olerácea) pulp as an oral contrast agent for magnetic resonance cholangiopancreatography

BACKGROUND

We evaluate the effectiveness of the Amazonian fruit pulp from Euterpe olerácea (popularly named Açaí) as a negative oral contrast agent applied to clinical routine. The use of such contrasts is particularly important in magnetic resonance cholangiopancreatography (MRCP) to reduce overlapping.

MATERIALS AND METHODS

We administered Açaí pulp to 5 nonsymptomatic subjects and 35 patients submitted to unspecific abdominal MR imaging, intending to set up optimal protocol. In 8 MRCP examinations, contrast and image effects were assessed and graded blindly by 2 independent radiologists. Quantitative analysis was performed by Wilcoxon test as to verify the potential of the Açaí to eliminate overlap signal over the pancreaticobiliary tract. Adverse effects and subject tolerance were also addressed.

RESULTS

The Açaí pulp elicited a local brightness decrease in T2-weighted images. The depiction of gallbladder, common bile duct, ampulla of Vater, and pancreatic duct was markedly improved after Açaí ingestion because of the suppression of the overlapping from bowel loops and gastric content (P < 0.01). All patients considered Açaí palatable, and no side effect was registered.

CONCLUSIONS

The Açaí pulp can be used routinely in MRCP studies as a natural, safe, and inexpensive negative oral contrast agent with high efficacy and patient acceptance.

Update on endoscopic treatment of chronic pancreatitis

Endoscopic therapy has been increasingly recognized as the effective therapy in selected patients with chronic pancreatitis. Utility of endotherapy in various conditions occurring in chronic pancreatitis is discussed. Its efficacy, limitations, and alternatives are addressed. For the best management of these complex entities, a multidisciplinary approach involving expertise in all pancreatic specialties is essential to achieve the goal.

Secretin-enhanced MRCP: proceed with cautious optimism

Magnetic resonance imaging (MRI) is a safe and universally available test that has much appeal to generalists and subspecialists evaluating patients with pancreatic disease. Testoni et al. report the clinical utility of magnetic resonance pancreaticocholangiography (MRCP) and secretin-enhanced MRCP in the evaluation of patients with asymptomatic abnormalities in pancreatic enzymes. The authors report that chronic pancreatitis changes will be seen in up to a third of patients with asymptomatic elevations in pancreas enzymes when compared with age-matched controls. The changes described on MRI and secretin-enhanced MRI are not in question, but the clinical significance of these changes is unknown. The authors rightly report that some of the changes seen may be age related, nonspecific, and of unknown clinical significance. Any new imaging and diagnostic test needs to be interpreted with caution until appropriate prospective clinical trials have been performed. It appears that secretin stimulation enhances the diagnostic accuracy of MRCP for the detection of minor changes in the pancreatic duct and parenchyma. Gastroenterologists are encouraged to proceed with cautious optimism when using MRI for the evaluation of early chronic pancreatitis.

Diagnosis of chronic pancreatitis by using apparent diffusion coefficient measurements at 3.0-T MR following secretin stimulation

PURPOSE

To prospectively measure pancreatic apparent diffusion coefficient (ADC) before and after secretin administration in subjects with and without chronic pancreatitis (CP) who underwent magnetic resonance (MR) cholangiopancreatography with diffusion-weighted (DW) imaging at 3.0 T.

MATERIALS AND METHODS

Institutional review board approval of this HIPAA-compliant study was obtained. Healthy volunteers, and patients with suspected and/or known CP who were scheduled for MR cholangiopancreatography, were recruited and gave written informed consent. All subjects underwent 3.0-T MR cholangiopancreatography, including serial DW imaging sequences (b = 0, 200, and 400 sec/mm(2)) acquired for 15 minutes after secretin administration. The referring gastroenterologist then classified subjects as healthy or with mild or severe CP, given endoscopic retrograde cholangiopancreatographic and/or clinical findings. CP severity was analyzed for sex and age. Mean presecretin and maximum postsecretin ADCs were compared between groups. Pairwise mean ADCs for healthy versus mild CP patient groups, healthy versus severe CP patient groups, and mild versus severe CP patient groups were compared. Presecretin ADC threshold levels for CP discrimination were calculated (P < .05).

RESULTS

Thirty-two subjects were imaged; four CP patients were excluded owing to severe artifact, and the remaining 28 (15 healthy patients, five with mild CP, and eight with severe CP) comprised the study population. All CP patients had endoscopic retrograde cholangiopancreatographic confirmation of CP. Mild or severe CP patients were older than healthy patients; sex distribution did not vary among groups. Mean presecretin and maximum postsecretin ADCs were higher in healthy patients than in either mild or severe CP groups (P < .01), but did not vary between mild and severe CP groups (P = .25-0.28). An ADC of less than 220 x 10(-5) mm(2)/sec was optimal for delineating between healthy and CP patients.

CONCLUSION

Pancreatic ADC obtained with DW imaging at 3.0 T prior to secretin administration may help diagnose CP; postsecretin ADC response does not distinguish CP severity.

Assessment of chronic pancreatitis: utility of diffusion-weighted MR imaging with secretin enhancement

PURPOSE

To retrospectively measure and compare changes in pancreatic apparent diffusion coefficient (ADC) following secretin administration in patients with and those without chronic pancreatitis (CP) who underwent magnetic resonance (MR) cholangiopancreatography with diffusion-weighted (DW) imaging.

MATERIALS AND METHODS

This retrospective HIPAA-compliant study was approved by the authors' institutional review board, with waiver of informed consent. Eighty-nine patients were categorized by the referring gastroenterologist as having no CP (n = 37), mild CP (n = 33), or severe CP (n = 19) on the basis of Cambridge criteria and/or clinical course. Mean age was 52.2 years (range, 21-82 years) in women and 54.3 years (range, 32-81 years) in men. Patients underwent 1.5-T MR cholangiopancreatography, including DW sequences (b = 0, 100, and 400 sec/mm(2)) performed serially for 10 minutes after secretin injection. Severity level of CP was analyzed for sex (Fisher exact test) and age (analysis of variance) differences. Pairwise comparisons of mean ADCs for each parameter (no CP vs mild CP, no CP vs severe CP, mild CP vs severe CP) were performed (Mann-Whitney test). Threshold values of non-secretin-enhanced ADC for pancreatitis discrimination were calculated with receiver operating characteristic analysis. P < .05 was considered to show a significant difference.

RESULTS

Patients with severe CP were more likely to be men than were those without pancreatitis; there were no significant age differences between groups. Mean nonenhanced and maximum secretin-enhanced ADCs were higher in patients without CP than in those with mild or severe CP but did not vary between those with mild and severe CP. Percentage increase in ADC after secretin injection and time to peak ADC did not vary among groups. An ADC of less than 179 x 10(-5) mm(2)/sec was optimal for delineating normal pancreas from CP groups.

CONCLUSION

In symptomatic patients, baseline pancreatic ADC obtained with DW imaging prior to secretin administration may aid in diagnosis of CP and assessment of its severity; ADC response to secretin administration may be less useful.

Endoscopic management of acute and chronic pancreatitis

Endoscopic therapy has been increasingly recognized as the effective therapy in selected patients with acute pancreatitis and chronic pancreatitis (CP). Utility of endotherapy in various conditions occurring in acute pancreatitis and CP is discussed. Its efficacy, limitations, and alternatives are addressed. For the best management of these complex entities, a multidisciplinary approach involving expertise in all pancreatic specialties is essential to achieve the goal.

Quantitative secretin MRCP (MRCPQ): results in 215 patients with known or suspected pancreatic pathology

Secretin magnetic resonance cholangiopancreatography quantification (MRCPQ) of pancreatic exocrine function correlates well with steatorrhoea and conventional, non-invasive function tests. We report MRCPQ results in a variety of pancreatic conditions. A total of 215 patients [107 male, mean age 46 years (14-78)] were studied. A multi-slice MRCP sequence was performed before and at 2-min intervals after 0.1 ml/kg IV secretin. Change in small intestinal water volume was plotted against time and the flow rate derived from the gradient. Patients were classified using clinical history, MRCP, MR imaging, computed tomography (CT) [150/215 (70%)] and endoscopic retrograde cholangiopancreatography (ERCP) [56/215 (26%)] findings but not MRCPQ results. Mean, standard deviation and 95% confidence intervals were calculated. The one way ANOVA and Student's t-test were used for statistical analysis. Seventy-six patients had chronic pancreatitis, 26 were post-surgical, 34 post-acute pancreatitis, six atrophic pancreatopathy, eight with obstruction, 15 divisum, ten sphincter of Oddi dysfunction, 26 normal and 14 miscellaneous. Significant differences were observed between normals (mean+/-SD; 7.4 +/- 2.9 ml/min) and severe chronic pancreatitis (5.3 +/- 2.4) (P = 0.018), pancreatic atrophy (3.8 +/- 3.1) (P = 0.013) or duct obstruction (5.3 +/- 2.4) (P = 0.047)) and between moderate (7.0 +/- 3.0) (P = 0.03) and severe chronic pancreatitis. MRCPQ can be used to quantify function across the spectrum of pancreatic disease and showed significant differences between several different pathologies.

Secretin-stimulating MRCP in patients with pancreatobiliary maljunction and occult pancreatobiliary reflux: direct demonstration of pancreatobiliary reflux

We propose the hypothesis that the enlargement of the common bile duct (CBD) or gallbladder (GB) that is occasionally demonstrated on magnetic resonance cholangiopancreatography (MRCP) after secretin stimulation is caused by pancreatobiliary reflux. Recently, occult pancreatobiliary reflux (OPR) has been demonstrated in patients without morphological pancreatobiliary maljunction (MPBM). The aim of this study was to evaluate the efficacy of secretin-stimulating MRCP (SMRCP) in the diagnosis of pancreatobiliary reflux. The study included 14 patients with MPBM and 32 patients with a normal pancreatobiliary junction. OPR was evaluated by bile collection and diagnosed in seven of the 32 patients. All the patients underwent SMRCP; the related findings were considered positive when enlargement of the CBD or GB was observed. Positive findings on SMRCP were observed in all MPBM patients. In the patients with normal pancreatobiliary junction, there was significant difference between the mean amylase levels in the patients with positive and negative SMRCP findings (mean, 4,755.7 and 29.7 IU/l). The sensitivity and specificity of SMRCP for diagnosing OPR was 85.7% and 68.0%, respectively. SMRCP provides a non invasive method for excluding PBR and can identify patients who could benefit from bile duct sampling to diagnose OPR.

Chronic pancreatitis: challenges and advances in pathogenesis, genetics, diagnosis, and therapy

Chronic pancreatitis (CP) is characterized by progressive pancreatic damage that eventually results in significant impairment of exocrine as well as endocrine functions of the gland. In Western societies, the commonest association of chronic pancreatitis is alcohol abuse. Our understanding of the pathogenesis of CP has improved in recent years, though important advances that have been made with respect to delineating the mechanisms responsible for the development of pancreatic fibrosis (a constant feature of CP) following repeated acute attacks of pancreatic necroinflammation (the necrosis-fibrosis concept). The pancreatic stellate cells (PSCs) are now established as key cells in fibrogenesis, particularly when activated either directly by toxic factors associated with pancreatitis (such as ethanol, its metabolites or oxidant stress) or by cytokines released during pancreatic necroinflammation. In recent years, research effort has also focused on the genetic abnormalities that may predispose to CP. Genes regulating trypsinogen activation/inactivation and cystic fibrosis transmembrane conductance regulator (CFTR) function have received particular attention. Mutations in these genes are now increasingly recognized for their potential 'disease modifier' role in distinct forms of CP including alcoholic, tropical, and idiopathic pancreatitis. Treatment of uncomplicated CP is usually conservative with the major aim being to effectively alleviate pain, maldigestion and diabetes, and consequently, to improve the patient's quality of life. Surgical and endoscopic interventions are reserved for complications such as pseudocysts, abscess, and malignancy.

Technology insight: applications of MRI for the evaluation of benign disease of the pancreas

This article reviews the role of MRI in the evaluation of benign pancreatic disease. Although MRI and magnetic resonance cholangiopancreatography (MRCP) are most often used to evaluate the liver and bile duct, technical advances such as the use of secretin stimulation also allow for high-quality imaging of the pancreas and pancreatic ductal system. Secretin-stimulated MRCP (S-MRCP) can aid the diagnosis of acute and chronic pancreatitis, and delineate ductal pathology such as benign strictures and duct leaks. There seems to be a role for S-MRCP in the assessment of pancreatic function and (possibly) sphincter of Oddi dysfunction. When endoscopic or surgical therapy is planned, S-MRCP can help to establish a diagnosis as well as offer a 'road map' to guide therapy. S-MRCP is noninvasive and almost entirely without risk to the patient, which gives it a distinct advantage over traditional endoscopic methods of diagnosis for conditions such as pancreas divisum and other ductal pathology. The information provided by S-MRCP, obtained before endoscopic or surgical therapy is attempted, can assist the patient and physician in making a fully informed decision with regard to the risks and probable benefits of any planned intervention.

Evaluation of the stimulating effect of a low dose of secretin compared to the standard dose on the exocrine pancreas with MRCP: preliminary results in normal subjects (MRCP quantification of secretin stimulation)

BACKGROUND

Secretin administration during MRCP improves depiction of pancreatic ducts and allows assessment of pancreatic exocrine secretions. However, secretin increases the cost of secretin-enhanced MRCP (S-MRCP). The aim of this study was to quantify using MRCP the stimulating effect of 0.3 CU/kg of secretin and to compare it to the standard dose (1 CU/kg).

METHODS

Ten healthy volunteers underwent four S-MRCP (two for each dose). Pancreatic exocrine secretions were quantified by pancreatic flow output (PFO) and total excreted volume (TEV), derived from a linear regression between MR calculated pancreatic exocrine volumes and time. Two readers analysed individually all sets of images.

RESULTS

A linear increase of pancreatic exocrine volumes was observed after administration of both doses of secretin. Intra-individual and inter-observer differences were not statistically significant (P > 0.05). The mean PFO and TEV, given for reader 1 only, were, respectively, 6.9 +/- 1.5 mL/min and 103 +/- 26 mL for the standard dose and 6.1 +/- 1.2 mL/min and 84 +/- 19 mL for the dose of 0.3 CU/kg. Differences between PFO and TEV obtained with the two doses of secretin were statistically significant for both readers (P < 0.05).

CONCLUSIONS

MRCP is a non-invasive, reproducible tool that allows quantification of pancreatic exocrine secretions during secretin stimulation. PFO and TEV calculated with the low dose were still in the range of previously reported reference values. The administration of 0.3 CU/kg of secretin can reduce significantly the cost of S-MRCP.

Diagnosis of early-stage chronic pancreatitis by secretin-enhanced magnetic resonance cholangiopancreatography

A diagnostic means of detecting chronic pancreatitis at an early stage, when the disease is still reversible, needs to be developed. Magnetic resonance cholangiopancreatography (MRCP) has recently been evolving as an important tool for the evaluation of chronic pancreatitis. In patients with moderate chronic pancreatitis, the pancreatic parenchyma displays an abnormal enhancement pattern on T1-weighted sequences after gadolinium administration. The presence of a signal intensity ratio of <1.7 in the arterial phase and/or delayed peak enhancement after contrast administration has a sensitivity of 92% and a specificity of 75% for the demonstration of early chronic pancreatitis. The secretin-induced pancreatic T2 signal intensity changes are significantly reduced in patients with a mild exocrine pancreatic insufficiency as compared with healthy volunteers. MRCP visualizes fluid in the pancreatic and biliary ducts as high signal intensity on heavily T2-weighted sequences. However, visualization of normal or minimally dilated pancreatic ducts by MRCP is more challenging because of their small size. Secretin administration stimulates fluid and bicarbonate secretion by the exocrine pancreas; consequently, it improves the pancreatic duct and side-branch delineation and allows an evaluation of the exocrine pancreatic function. Side-branch ectasia, mild ductal dilatation with loss of the normal gentle taper, and mural irregularities are the pathognomonic MRCP features of early-stage chronic pancreatitis. Through measurement of the duodenal filling, secretin-MRCP allows quantitative assessment of the exocrine pancreatic function, even in patients with a mild exocrine insufficiency. The morphology of the pancreatic ducts, particularly in the early stages, does not always correlate with the functional status. MRCP permits visualization of the ductal changes and furnishes functional information on the pancreas; this combination may enhance its diagnostic accuracy so that MRCP can become a valuable diagnostic means in early-stage chronic pancreatitis.

Pancreatic imaging: current and emerging technologies

This review discusses the current imaging modalities for the diagnosis and staging of solid and cystic pancreatic lesions and for the assessment of acute and chronic pancreatitis, and the future role of emerging technologies in the management of pancreatic diseases. Multidetector row spiral computed tomography is superior to conventional single-detector row spiral computed tomography in the detection and staging of pancreatic adenocarcinoma. Positron emission tomography is a sensitive but relatively nonspecific diagnostic modality. Positron emission tomography-computed tomography fusion may improve the staging accuracy for pancreatic cancer. Echo-enhanced ultrasound may have an emerging role in evaluating pancreatic masses. Endoscopic ultrasound with fine needle aspiration for cytology is the single best method for diagnosis and staging of nonmetastatic pancreatic cancer with a high accuracy for determining tumor resectability. In acute pancreatitis, a modification of the standard computed tomography severity index, which places greater emphasis on extrapancreatic complications, has shown superior correlation with various patient outcome measures. Endoscopic retrograde cholangiopancreatography is still the test of choice for morphological evaluation of chronic pancreatitis, whereas magnetic resonance cholangiopancreatography offers a noninvasive alternative in selected patients. Endoscopic ultrasound can be useful for detecting early chronic pancreatitis. Secretin-stimulated imaging techniques may eventually provide a noninvasive method of reliably assessing pancreatic exocrine function.