Dynamic secretin-enhanced MR cholangiopancreatography

Imaging Diagnosis and Management of Fistulas in Pancreatitis

Pancreatic fistula is a highly morbid complication of pancreatitis. External pancreatic fistulas result when pancreatic secretions leak externally into the percutaneous drains or external wound (following surgery) due to the communication of the peripancreatic collection with the main pancreatic duct (MPD). Internal pancreatic fistulas include communication of the pancreatic duct (directly or via intervening collection) with the pleura, pericardium, mediastinum, peritoneal cavity, or gastrointestinal tract. Cross-sectional imaging plays an essential role in the management of pancreatic fistulas. With the help of multiplanar imaging, fistulous tracts can be delineated clearly. Thin computed tomography sections and magnetic resonance cholangiopancreatography images may demonstrate the communication between MPD and pancreatic fluid collections or body cavities. Endoscopic retrograde cholangiography (ERCP) is diagnostic as well as therapeutic. In this review, we discuss the imaging diagnosis and management of various types of pancreatic fistulas with the aim to sensitize radiologists to timely diagnosis of this critical complication of pancreatitis.

Outcomes and predictors of response to endotherapy in pancreatic ductal disruptions with refractory internal and high-output external fistulae

Backgrounds/Aims

Endoscopic retrograde cholangiopancreatography (ERCP) remains the primary treatment for a subset of patients with pancreatic fistulae. The objective of this study was reporting outcomes of ERCP and predictors of resolution in patients with pancreatic fistulae refractory to conservative therapy.

Methods

Retrospective review of patients who underwent ERCP and pancreatic stent placement for pancreatic fistula not responding to medical therapy was performed. Clinical features, laboratory parameters, radiological features and pancreatogram findings were noted. Clinical resolution of fistula was the primary outcome measure.

Results

Sixty-eight patients underwent ERCP for high-output pancreatic fistula (Mean age 34.1 years, 91.1% males, 35/68 chronic pancreatitis, 52.9% alcohol etiology). Internal fistulae (pancreatic ascites, pleural effusion, or pericardial effusion) were seen in 55 (80.9%) patients and external fistula in 13 (19.1%) patients. Technical success for ERCP was 92.6% (63/68). Leak was seen in 98.4% (62/63). The most common leak site was body (69.8%). Multiple leak sites were seen in 23.1%. Pancreatic stricture was found in 36.5%. In 44 (69.4%) patients, stent was placed beyond the site of the leak. Resolution at six weeks was achieved in 76.4% (52/68). On univariate and multivariate analyses, placement of stent beyond site of leak was significantly associated with resolution of high-output fistulae (3/41 [7.3%] vs. 5/19 [26.3%], p = 0.03; odds ratio: 6.5, 95% confidence interval: 1.211-34.94).

Conclusions

In our experience, ERCP was successful in 76% of patients with pancreatic fistulae refractory to conservative therapy. Stent placement beyond the site of leak was associated with higher resolution of fistulae.

Pancreatic Cystic Neoplasms

Early detection of high-risk pancreatic cystic lesions enables potentially curative surgical resection, and early detection of lesions without worrisome features may lead to appropriate surveillance. Regrettably, differentiating premalignant and malignant cysts from nonmalignant ones remains challenging. However, emerging additional diagnostic tools, including the needle biopsy with microforceps and needle-based confocal laser endomicroscopy, are of exciting potential along with cyst fluid analysis".

Various Modalities Accurate in Diagnosing a Disrupted or Disconnected Pancreatic Duct in Acute Pancreatitis: A Systematic Review

BACKGROUND

Severe pancreatitis may result in a disrupted pancreatic duct, which is associated with a complicated clinical course. Diagnosis of a disrupted pancreatic duct is not standardized in clinical practice or international guidelines. We performed a systematic review of the literature on imaging modalities for diagnosing a disrupted pancreatic duct in patients with acute pancreatitis.

METHODS

A systematic search was performed in PubMed, Embase and Cochrane library databases to identify all studies evaluating diagnostic modalities for the diagnosis of a disrupted pancreatic duct in acute pancreatitis. All data regarding diagnostic accuracy were extracted.

RESULTS

We included 8 studies, evaluating five different diagnostic modalities in 142 patients with severe acute pancreatitis. Study quality was assessed, with proportionally divided high and low risk of bias and low applicability concerns in 75% of the studies. A sensitivity of 100% was reported for endoscopic ultrasound and endoscopic retrograde cholangiopancreatography. The sensitivity of magnetic resonance cholangiopancreatography with or without secretin was 83%. A sensitivity of 92% was demonstrated for a combined cohort of secretin-magnetic resonance cholangiopancreatography and magnetic resonance cholangiopancreatography. A sensitivity of 100% and specificity of 50% was found for amylase measurements in drain fluid compared with ERCP.

CONCLUSIONS

This review suggests that various diagnostic modalities are accurate in diagnosing a disrupted pancreatic duct in patients with acute pancreatitis. Amylase measurement in drain fluid should be standardized. Given the invasive nature of other modalities, secretin-magnetic resonance cholangiopancreatography or magnetic resonance cholangiopancreatography would be recommended as first diagnostic modality. Further prospective studies, however, are needed.

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.

First Report of Sublingual Gland Ducts: Visualization by Dynamic MR Sialography and Its Clinical Application

This study was done to determine whether the sublingual gland ducts could be visualized and/or their function assessed by MR sialography and dynamic MR sialography and to elucidate the clinical significance of the visualization and/or evaluation of the function of sublingual gland ducts by clinical application of these techniques. In 20 adult volunteers, 19 elderly volunteers, and 7 patients with sublingual gland disease, morphological and functional evaluations were done by MR sialography and dynamic MR sialography. Next, four parameters, including the time-dependent changes (change ratio) in the maximum area of the detectable sublingual gland ducts in dynamic MR sialographic images and data were analyzed. Sublingual gland ducts could be accurately visualized in 16 adult volunteers, 12 elderly volunteers, and 5 patients. No significant differences in the four parameters in detectable duct areas of sublingual glands were found among the three groups. In one patient with a ranula, the lesion could be correctly diagnosed as a ranula by MR sialography because the mass was clearly derived from sublingual gland ducts. This is the first report of successful visualization of sublingual gland ducts. In addition, the present study suggests that MR sialography can be more useful in the diagnosis of patients with lesions of sublingual gland ducts.

Disconnected pancreatic duct syndrome: Updated review on clinical implications and management

Disconnected Pancreatic Duct Syndrome (DPDS) is an important but often overlooked complication of acute necrotising pancreatitis (ANP) that occurs due to necrosis of the main pancreatic duct (PD). This segmental necrosis leads on to disconnection between the viable upstream pancreatic parenchyma and the duodenum. The disconnected and functional segment of pancreas continues to secrete pancreatic juice that is not drained into the gastrointestinal tract and lead on to recurrent pancreatic fluid collections (PFC), refractory external pancreatic flstulae and chronic abdominal pain/recurrent pancreatitis. Because of lack of awareness of this important complication of ANP, the diagnosis of DPDS is usually delayed. The delay in diagnosis increases the morbidity of the disease as well as increase the cost of treatment and duration of hospital stay. Surgery has remained the cornerstone for management of patients with DPDS. The conventional surgical approaches have been either resection or internal drainage procedures. Surgery for DPDS in the setting of ANP is often difficult due to presence of local inflammation and extensive venous collaterals in the operative field due to splenic vein thrombosis and therefore is associated with significant morbidity. Advancement in therapeutic endoscopy, especially advent of therapeutic endoscopic ultrasound has opened an exciting new field of minimally invasive therapeutic options for management of DPDS. The present review discusses the current understanding of the clinical manifestations, imaging features and management strategies in patients with DPDS.

Pancreas divisum inversus

Pancreatic duct variations are usually diagnosed incidentally, in particular when using magnetic resonance cholangiopancreatography (MRCP), the most accurate imaging modality for depicting the pancreatic ductal system. However, the frequency and the embryologic development of pancreatic variants have not been well investigated. The purpose of this prospective study was to investigate the frequency of pancreatic ductal variants, providing potential explanations of their embryologic basis. The pancreatic ductal anatomies of 202 patients with mean ± standard deviation (SD) age of 54 ± 27 years, 56% females, who underwent MRCP for different indications between April 2018 and March 2019, were prospectively collected. Normal pancreatic ductal variants were identified in 196 cases (97%), and variants of pancreas divisum in six cases (3%). In the type C variant of the normal pancreatic anatomy, found in 3% of the cases, the dorsal duct was joined to the ventral duct while the accessory duct did not communicate with the dorsal duct. Unlike the classic type C variant, in our cases, the accessory pancreatic duct (APD) was long (mean ± SD of 58 ± 8.5 mm) and originated in the lower portion of the pancreatic head, caudally to the duct of Wirsung. This was a new subtype of the type C variant or a new variant, which could be called "pancreas divisum inversus"; the APD could be called the isolated duct of Santorini. Reporting this new variant could increase knowledge regarding the pancreatic anatomy in order to avoid misdiagnosis and to help in better understanding pancreatic diseases and their relative treatment. Clin. Anat., 33:646-652, 2020. © 2019 Wiley Periodicals, Inc.

Advanced MR Imaging of the Pancreas

MR imaging can be optimized to evaluate a spectrum of pancreatic disorders with advanced sequences aimed to provide quantitative results and increase MR diagnostic capabilities. The pancreas remains a challenging organ to image because of its small size and location deep within the body. Besides its anatomic limitations, pancreatic pathology can be difficult to identify in the early stages. For example, subtle changes in ductal anatomy and parenchymal composition seen in early chronic pancreatitis are imperceptible with other modalities, such as computed tomography. This article reviews the application of MR imaging techniques and emerging MR sequences used in pancreas imaging.

Reporting of acute pancreatitis by radiologists-time for a systematic change with structured reporting template

Acute pancreatitis has a wide array of imaging presentations. Various classifications have been used in the past to standardize the terminology and reduce confusing and redundant terms. We aim to review the historical and current classifications of acute pancreatitis and propose a new reporting template which can improve communication between various medical teams by use of appropriate terminology and structured radiology template. The standardized reporting template not only conveys the most important imaging findings in a simplified yet comprehensive way but also allows structured data collection for future research and teaching purposes.

Diagnosis and management of pancreatic cystic neoplasms: current evidence and guidelines

Pancreatic cystic neoplasms (PCN) are a heterogeneous group of pancreatic cysts that include intraductal papillary mucinous neoplasms, mucinous cystic neoplasms, serous cystic neoplasms and other rare cystic lesions, all with different biological behaviours and variable risk of progression to malignancy. As more pancreatic cysts are incidentally discovered on routine cross-sectional imaging, optimal surveillance for patients with PCN is becoming an increasingly common clinical problem, highlighting the need to balance cancer prevention with the risk of (surgical) overtreatment. This Review summarizes the latest developments in the diagnosis and management of PCN, including the quality of available evidence. Also discussed are the most important differences between the PCN guidelines from the American Gastroenterological Association, the International Association of Pancreatology and the European Study Group on Cystic Tumours of the Pancreas, including diagnostic and follow-up strategies and indications for surgery. Finally, new developments in the management of patients with PCN are addressed.

Endoscopic transpapillary drainage in disconnected pancreatic duct syndrome after acute pancreatitis and trauma: long-term outcomes in 31 patients

Background

Conventionally, disconnected pancreatic duct syndrome is treated surgically. Endoscopic management is associated with lesser morbidity and mortality than that observed with surgery and shows similar success rates. However, limited data are available in this context. We evaluated the efficacy of endotherapeutic management for this syndrome.

Methods

We prospectively obtained data of patients with disconnected pancreatic duct syndrome between September 2008 and January 2016. Demographic and clinical data were assessed, and factors affecting clinical outcomes were statistically analyzed.

Results

Thirty-one patients underwent 40 endoscopic transpapillary procedures, and 1 patient developed an infection after prosthesis insertion. Etiological contributors to disconnected pancreatic duct syndrome were abdominal trauma (52%) and acute necrotizing pancreatitis (48%). The median interval between the appearance of pancreatic leaks and disconnected pancreatic duct syndrome was 6.6 months (range 0.5–84 months). The median follow-up after the last treatment procedure was 38 months (range 17–99 months). Patients with complete main pancreatic duct disruption in the body/tail showed a low risk of pancreatic atrophy (P = 0.009). This study highlighted the significant correlation between endoscopic transpapillary drainage and clinical success (P = 0.014).

Conclusions

Disconnected pancreatic duct syndrome is not an uncommon sequel of pancreatic injury, and much of the delayed diagnosis is attributable to a lack of knowledge regarding this disease. Endoscopic transpapillary intervention with ductal stenting is an effective and safe treatment for this condition.

Advanced MR Imaging Techniques for Pancreas Imaging

Advances in MR imaging with optimization of hardware, software, and techniques have allowed for an increased role of MR in the identification and characterization of pancreatic disorders. Diffusion-weighted imaging improves the detection and staging of pancreatic neoplasms and aides in the evaluation of acute, chronic and autoimmune pancreatitis. The use of secretin-enhanced MR cholangiography improves the detection of morphologic ductal anomalies, and assists in the characterization of pancreatic cystic lesions and evaluation of acute and chronic pancreatitis. Emerging MR techniques such as MR perfusion, T1 mapping/relaxometry, and MR elastography show promise in further evaluating pancreatic diseases.

The morphological and functional diagnosis of a rare entity: lipomatous pseudohypertrophy of the pancreas

Lipomatous pseudohypertrophy of the pancreas is a rare entity characterized by a replacement, focal or diffuse, of the normal pancreatic tissue by mature fatty tissue. Its definitive diagnosis is made based on histopathologic analysis. Nevertheless, typical imaging findings can allow a non-invasive diagnosis and help its clinical approach.

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.

The Value of Secretin-Enhanced MRCP in Patients With Recurrent Acute Pancreatitis

OBJECTIVE

The purpose of this study is to assess the additional value of secretin-enhanced MRCP over conventional (non-secretin-enhanced) MRCP in diagnosing disease in patients with recurrent acute pancreatitis.

MATERIALS AND METHODS

A retrospective review of a radiology database found 72 patients with recurrent acute pancreatitis who had secretin-enhanced MRCP and ERCP correlation within 3 months of each other between January 2007 and December 2011. Of these patients, 54 had no history of pancreatic tumor or surgery and underwent MRI more than 3 months after an episode of acute pancreatitis. In addition, 57 age- and sex-matched control subjects with secretin-enhanced MRCP and ERCP correlation and without a diagnosis of recurrent acute pancreatitis or chronic pancreatitis were enrolled as the control group. All studies were anonymized, and secretin-enhanced MRCP images (image set A) were separated from conventional 2D and 3D MRCP and T2-weighted images (image set B). Image sets A and B for each patient were assigned different and randomized case numbers. Two blinded reviewers independently assessed both image sets for ductal abnormalities and group A image sets for exocrine response to secretin.

RESULTS

There were statistically significantly more patients with recurrent acute pancreatitis with reduced exocrine function compared with patients in the control group (32% vs 9%; p < 0.01) on secretin-enhanced images. Patients with recurrent acute pancreatitis were more likely to have side branch dilation (p = 0.02; odds ratio, 3.6), but not divisum, compared with the control group. Secretin-enhanced images were superior to non-secretin-enhanced images for detecting ductal abnormalities in patients with recurrent acute pancreatitis, with higher sensitivity (76% vs 56%; p = 0.01) and AUC values (0.983 vs 0.760; p < 0.01).

CONCLUSION

Up to one-third of patients with recurrent acute pancreatitis showed exocrine functional abnormalities. Secretin-enhanced MRCP had a significantly higher yield for ductal abnormalities than did conventional MRI and should be part of the MRCP protocol for investigation of patients with recurrent acute pancreatitis.

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.

Chronic pancreatitis

Chronic pancreatitis describes a wide spectrum of fibro-inflammatory disorders of the exocrine pancreas that includes calcifying, obstructive, and steroid-responsive forms. Use of the term chronic pancreatitis without qualification generally refers to calcifying chronic pancreatitis. Epidemiology is poorly defined, but incidence worldwide seems to be on the rise. Smoking, drinking alcohol, and genetic predisposition are the major risk factors for chronic calcifying pancreatitis. In this Seminar, we discuss the clinical features, diagnosis, and management of chronic calcifying pancreatitis, focusing on pain management, the role of endoscopic and surgical intervention, and the use of pancreatic enzyme-replacement therapy. Management of patients is often challenging and necessitates a multidisciplinary approach.

The utility of secretin-enhanced MRCP in diagnosing congenital anomalies

PURPOSE

To assess the additional value of secretin-enhanced MRCP (SMRCP) over conventional MRCP in diagnosing divisum.

METHODS

Retrospective HIPAA-compliant and IRB-approved review found 140 patients with SMRCP and ERCP correlation within 6 months of each other. All studies were anonymized and the SMRCP images (SMRCP image set) were separated from 2D and 3D MRCP and axial and coronal T2-weighted images (conventional MRI image set). Each image set on each patient was assigned different and randomized case numbers. Two reviewers (R1 and R2) independently reviewed the image sets for divisum vs. no divisum, complete divisum vs. incomplete divisum, and the certainty of diagnosis (1 = definitely certain, 2 = moderately certain, and 3 = unsure). ERCP findings were taken as gold standard.

RESULTS

There was no difference in age and gender between the divisum (n = 97, with 13 incomplete divisum) and no divisum (n = 43) groups. In diagnosing divisum anatomy, the sensitivity was higher for SMRCP compared to conventional MRI for R1 (84.5 vs. 72.2, p = 0.02) but not R2 (89.7 vs. 84.4, p = 0.25). The specificity was higher in SMRCP image set compared to conventional MRI (R1: 88.1 vs. 76.2, p = 0.01; R2: 81.4 vs. 65.1, p < 0.001). The mean area under ROC curve was higher for SMRCP image set (R1: 0.86 vs. 0.74, p = 0.01; R2: 0.87 vs. 0.74, p = 0.01). The certainty of diagnosis was higher in SMRCP image set compared to conventional MRI (p = 0.02 for both reviewers). SMRCP was not found to be superior in distinguishing incomplete from complete divisum. The main reasons for erroneous SMRCP diagnosis were the presence of an ansa loop in the main duct and ductal strictures due to chronic pancreatitis.

CONCLUSION

Even though the reviewers had more sequences (axial and coronal) to evaluate in the non-secretin image set, there was some improvement in diagnosing divisum with SMRCP.

Incremental value of secretin-enhanced magnetic resonance cholangiopancreatography in detecting ductal communication in a population with high prevalence of small pancreatic cysts

PURPOSE

We investigated the incremental diagnostic yield of S-MRCP in a population with high prevalence of small pancreatic cysts.

METHODS

Standard MRCP protocol was performed with and without secretin using 1.5 T units in subjects undergoing pancreatic screening because of a strong family history of pancreatic cancer as part of the multicenter Cancer of the Pancreas Screening-3 trial (CAPS 3). All studies were reviewed prospectively by two independent readers who recorded the presence and number of pancreatic cysts, the presence of visualized ductal communication before and after secretin, and the degree of confidence in the diagnoses.

RESULT

Of 202 individuals enrolled (mean age 56 years, 46% males), 93 (46%) had pancreatic cysts detected by MRCP, and 64 of the 93 had pre-and post-secretin MRCP images available for comparison. Data from the 128 readings show that 6 (6/128=4.7%) had ductal communication visualized only on the secretin studies compared to pre-secretin studies (odds ratio 1.28, p=0.04). In addition, there was a statistically significant increase in confidence in reporting ductal communication after secretin compared to before secretin (p<0.0005).

CONCLUSION

At 1.5 T MRI, the use of secretin can improve the visualization of ductal communication of cystic pancreatic lesions.

Approach to patients with suspected chronic pancreatitis: a comprehensive review

Chronic pancreatitis (CP) represents a significant health care burden in the United States. Diagnosing it early and accurately is important for the efficient management of these patients. However, the early diagnosis of CP, when structural and functional pancreatic changes are subtle, remains difficult. Complicating this is the large cohort of patients with nonspecific abdominal pain who are often suspected of having early CP and who utilize significant health care resources in attempts at diagnosis and management. We present a review of the current diagnostic tests available for making an early diagnosis of CP. We further report our approach to patients suspected of having CP based on the available literature.

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.

Magnetic resonance imaging of pancreatitis: An update

Magnetic resonance (MR) imaging plays an important role in the diagnosis and staging of acute and chronic pancreatitis and may represent the best imaging technique in the setting of pancreatitis due to its unmatched soft tissue contrast resolution as well as non-ionizing nature and higher safety profile of intravascular contrast media, making it particularly valuable in radiosensitive populations such as pregnant patients, and patients with recurrent pancreatitis requiring multiple follow-up examinations. Additional advantages include the ability to detect early forms of chronic pancreatitis and to better differentiate adenocarcinoma from focal chronic pancreatitis. This review addresses new trends in clinical pancreatic MR imaging emphasizing its role in imaging all types of acute and chronic pancreatitis, pancreatitis complications and other important differential diagnoses that mimic pancreatitis.

Acinarization (parenchymal blush) observed during secretin-enhanced MRCP: clinical implications

OBJECTIVE

T2 hyperintensity of pancreatic acini during secretin-enhanced MRCP is called "acinarization." We sought to determine the clinical significance of this finding.

MATERIALS AND METHODS

Patients were selected if the radiology report included the phrases "acin*" (where * represented a wild card search) or "blush" using the institution's customized lexicon-search software. Sixty-seven consecutive patients without acinarization on secretin-enhanced MRCP who also underwent ERCP were enrolled as the control group. The intensity of acinarization was classified into three groups: grade 0, no visible acinarization; grade 1, barely visible parenchymal hyperintensity; or grade 2, easily visible parenchymal hyperintensity. ERCP findings of ductal abnormalities and basal pancreatic sphincter manometry were recorded.

RESULTS

There were higher frequencies of divisum (p = 0.001) and of a clinical history of recurrent acute pancreatitis (p < 0.001) and higher basal pancreatic sphincter of Oddi manometric pressure measurements (p = 0.008) in the acinarization group. There was no difference in the frequency of ERCP-defined chronic pancreatitis (p = 0.10) between the groups. In patients with acinarization, a higher mean sphincter pressure was seen in patients with more intense acinarization than in those with faint acinarization, but this difference was not significant (p = 0.22). Ampullary tumors were found in four patients with acinarization.

CONCLUSION

Acinarization probably occurs in patients with a propensity for increased pancreatic ductal pressure (i.e., patients with divisum, elevated basal pancreatic sphincter pressure, ampullary tumor) and adequate exocrine function (absence of severe chronic pancreatitis).

MR cholangiopancreatography of the pancreas and biliary system: a review of the current applications

MR cholangiopancreatography (MRCP) is still a rapidly evolving technique, but it has been already accepted as clinically useful and is widely used to evaluate biliary or pancreatic diseases. The advantages of this technique are that it does not use contrast media or ionizing radiation, it is noninvasive and complication free, and the examination is relatively short. MRCP has high sensitivity and specificity for diagnosing biliary dilatation and for determining the site and cause of stenosis. With further improvements of hardware and technique, MRCP is expected to replace diagnostic endoscopic retrograde cholangiopancreatography to examine the biliary and pancreatic ducts in the near future. The other applications include evaluation of primary sclerosing cholangitis, stenosis after liver transplantation, and bilioenteric anastomoses. This article reviews the current applications of MRCP in the evaluation of the pancreas and the biliary system.

Secretin-enhanced MR cholangiopancreatography: spectrum of findings

Magnetic resonance cholangiopancreatography (MRCP) is the most effective, safe, noninvasive magnetic resonance (MR) imaging technique for the evaluation of the pancreaticobiliary ductal system. The MRCP imaging technique has substantially improved during the past 2 decades and is based mainly on the acquisition of heavily T2-weighted MR images, with variants of fast spin-echo sequences. MRCP can also be performed by utilizing the hormone secretin, which stimulates a normal pancreas to secrete a significant amount of fluid while transiently increasing the tone of the sphincter of Oddi. The transient increase in the diameter of the pancreatic duct improves the depiction of the ductal anatomy, which can be useful in patients in whom detailed evaluation of the pancreatic duct is most desired because of a suspicion of pancreatic disease. Improved depiction of the ductal anatomy can be important in (a) the differentiation of side-branch intraductal papillary mucinous neoplasms from other cystic neoplasms and (b) the diagnosis and classification of chronic pancreatitis, the disconnected pancreatic duct syndrome, and ductal anomalies such as anomalous pancreaticobiliary junction and pancreas divisum. In patients examined after pancreatectomy, stimulation with secretin can give information about the patency of the pancreaticoenteric anastomosis. Duodenal filling during the secretin-enhanced phase of the MRCP examination can be used to estimate the excretory reserve of the pancreas. Secretin is well tolerated, and complications are rarely seen. Secretin-enhanced MRCP is most useful in (a) the evaluation of acute and chronic pancreatitis, congenital variants of the pancreaticoduodenal junction, and intraductal papillary mucinous neoplasms and (b) follow-up of patients after pancreatectomy.

Endoscopic therapy for pancreatic duct leaks and disruptions

Pancreatitis, whether acute or chronic, can lead to a plethora of complications, such as fluid collections, pseudocysts, fistulas, and necrosis, all of which are secondary to leakage of secretions from the pancreatic ductal system. Partial and side branch duct disruptions can be managed successfully by transpapillary pancreatic duct stent placement, whereas patients with disconnected pancreatic duct syndrome require more complex endoscopic interventions or multidisciplinary care for optimal treatment outcomes. This review discusses the current status of endoscopic management of pancreatic duct leaks and emerging concepts for the treatment of disconnected pancreatic duct syndrome.

Pancreatic duct patterns in acute pancreatitis: a MRI study

Objectives

To study the MRI findings of the pancreatic duct in patients with acute pancreatitis.

Materials and Methods

A total of 239 patients with acute pancreatitis and 125 controls were analyzed in this study. The severity of acute pancreatitis was graded using the MR severity index (MRSI) and the Acute Physiology And Chronic Healthy Evaluation II(APACHE II) scoring systems. The number of main pancreatic duct (MPD) segments visualized, and both MPD diameter and pancreatic duct disruption were noted and compared with the severity of acute pancreatitis.

Results

The frequency of MPD segment visualization in the control group was higher than that in the acute pancreatitis group (p<0.05). The number of MPD segments visualized was negatively correlated with the MRSI score (p<0.05) and the APACHE II score (p<0.05). There was no difference in the MPD diameter between the acute pancreatitis and control groups or among the patients with different severities of acute pancreatitis (p>0.05). The prevalence of pancreatic duct disruption was 7.9% in the acute pancreatitis group. The prevalences of pancreatic duct disruption were 4.8% and 15.3% in the mild and severe acute pancreatitis groups based on the APACHE II score, respectively, and were 0%, 5.7% and 43.5% in the mild, moderate and severe acute pancreatitis groups according the MRSI score, respectively. The prevalence of pancreatic duct disruption was correlated with the severity of acute pancreatitis based on the APACHE II score (p<0.05) and MRSI score (p<0.05).

Conclusion

The pancreatic duct in acute pancreatitis patients was of normal diameter. The number of MPD segments visualized and visible pancreatic duct disruption on MRI may be supplementary indicators for determining the severity of acute pancreatitis.

Does secretin add value in pediatric magnetic resonance cholangiopancreatography?

BACKGROUND

Secretin--a hormone that stimulates pancreatic exocrine secretion--is described to improve visualization of the pancreatic duct by magnetic resonance cholangiopancreatography (MRCP). In our pediatric practice, however, we have not observed substantial benefit with the use of secretin.

OBJECTIVE

To determine whether secretin dilates and improves visualization of the pancreatic duct in pediatric MRCP.

MATERIALS AND METHODS

Retrospective evaluation of secretin-enhanced MRCPs performed over a 15-month period. One reviewer measured the pancreatic duct pre- and post-secretin and two reviewers, blinded to the administration of secretin, assessed image quality and subjective duct visibility. Similar assessments of the biliary tree served as internal controls.

RESULTS

We reviewed 20 MRCPs in 17 children. Following secretin administration, there was a small (0.3 mm) but statistically significant increase in pancreatic duct diameter (P = 0.002) and small (<0.2 mm) but significant increase in intrahepatic bile duct diameter (P = 0.0104). On subjective review, there was no significant difference in image quality or duct visibility based on the administration of secretin.

CONCLUSION

Secretin induces dilatation of the pancreatic duct but the value of that effect in pediatric MRCP is suspect given the small change in duct diameter and the lack of improvement in image quality and duct visibility.

Secretin-enhanced MRCP: review of technique and application with proposal for quantification of exocrine function

OBJECTIVE

The purpose of this article is to present a proposal for quantification of exocrine function using secretin-enhanced MRCP for the diagnosis of chronic pancreatitis. The article also reviews the technique and application of secretin-enhanced MRCP in evaluating various pancreatic abnormalities.

SUBJECTS AND METHODS

One hundred thirty-four consecutive patients with chronic abdominal pain undergoing secretin-enhanced MRCP for suspected chronic pancreatitis were included. Patients were divided into four clinical groups (normal, equivocal, early chronic pancreatitis, established pancreatitis) on the basis of clinical symptoms and additional investigations, including CT (n=98), endoscopic pancreatic function test (n=65), endoscopic ultrasound (n=84), and ERCP (n=36). The volume of secretion was obtained by drawing a region of interest around T2 bright fluid secreted on postsecretin HASTE images. The maximal rate of secretion in response to secretin was obtained by plotting change in signal intensity on sequential postsecretin images. The analysis of variance test was used to compare the clinical groups with the volume and rate of secretion.

RESULTS

Significant volume differences were found between the normal and established pancreatitis groups (p<0.0001) as well as the equivocal and established pancreatitis groups (p<0.0005). Marginally significant differences were found between the normal and early pancreatitis groups (p=0.0150) as well as early and established pancreatitis groups (p=0.0351). Differences in the maximal rate of secretion were not statistically significant.

CONCLUSION

Secretory volume measurement of secretin-enhanced MRCP data is a simple method that brings out significant differences between normal, early, and established pancreatitis patients.

MR imaging of the abdomen and pelvis in infants, children, and adolescents

Recent developments in magnetic resonance (MR) imaging have profoundly changed the investigation of abdominal and pelvic disease in pediatrics. Motion reduction techniques, such periodically rotated overlapping parallel lines with enhanced reconstruction, or PROPELLER, have resulted in reliable imaging with quiet breathing. Faster imaging sequences minimize artifact and allow for more efficient studies. Diffusion-weighted imaging has become increasingly important in the evaluation of neoplastic disease, depicting disease with increased cellularity and helping to differentiate benign from malignant masses. MR enterography helps visualize intra- and extraluminal bowel pathologic conditions. MR cholangiopancreatography can depict congenital and acquired causes of pancreatic and biliary abnormalities. MR urography is an effective technique for a one-stop-shop evaluation of structural urinary tract abnormality and renal function. Three-dimensional acquisitions allow volumetric display of structures from multiple angles. Specialized techniques allow quantification of iron and fat in the viscera in children with hemolytic anemia and obesity, respectively. This article covers current techniques and strategies to perform and optimize MR imaging of the abdomen and pelvis in infants, children, and adolescents and describes important practical applications.

Italian consensus guidelines for chronic pancreatitis

This paper gives practical guidelines for diagnosis and treatment of chronic pancreatitis. Statements have been elaborated by working teams of experts, by searching for and analysing the literature, and submitted to a consensus process by using a Delphi modified procedure. The statements report recommendations on clinical and nutritional approach, assessment of pancreatic function, treatment of exocrine pancreatic failure and of secondary diabetes, treatment of pain and prevention of painful relapses. Moreover, the role of endoscopy in approaching pancreatic pain, pancreatic stones, duct narrowing and dilation, and complications was considered. Recommendations for most appropriate use of various imaging techniques and of ultrasound endoscopy are reported. Finally, a group of recommendations are addressed to the surgical treatment, with definition of right indications, timing, most appropriate procedures and techniques in different clinical conditions and targets, and clinical and functional outcomes following surgery.

MRI and S-MRCP findings in patients with suspected chronic pancreatitis: correlation with endoscopic pancreatic function testing (ePFT)

PURPOSE

To review magnetic resonance imaging (MRI) and secretin stimulated magnetic resonance cholangiopancreatography (S-MRCP) findings of patients with suspected chronic pancreatitis and compare them with endoscopic pancreatic function testing (ePFT).

MATERIALS AND METHODS

MRI and S-MRCP findings of 36 patients with clinically suspected chronic pancreatitis were reviewed. Baseline ductal changes, duodenal filling grades, and pancreatic duct caliber change (PDC) on S-MRCP, mean values of pancreatic anteroposterior (AP) diameter, signal intensity ratio (SIR) between pancreas and the spleen on T1-weighted fat saturated images, and arterial to venous (A/V) enhancement ratios were compared between groups of normal and abnormal pancreatic exocrine function determined by ePFT.

RESULTS

All patients (n = 24) with normal ePFT (HCO(3) >80 mEq/L) had grade 3 normal duodenal filling. Patients with abnormal ePFT (HCO(3) <80 mEq/L) (n = 12) had grade 1 (n = 1) and grade 2 (n = 11) diminished duodenal filling (P < 0.0001). PDC was 1.51 in the normal ePFT group versus 1.27 in the abnormal ePFT group (P = 0.01). No significant differences were found in terms of mean pancreatic AP diameter (21.8 vs. 19.8 cm), SIR (1.59 vs. 1.44), and A/V (1.08 vs. 1.01) between groups of normal/abnormal pancreatic exocrine function.

CONCLUSION

Despite discrepancies between pancreatic exocrine function and the findings on standard MRI/MRCP, the S-MRCP findings are comparable to ePFT in the evaluation of chronic pancreatitis.

Quality improvement for pancreatic cancer care: is regionalization a feasible and effective mechanism?

Variability exists in the quality of pancreatic cancer care provided in the United States. High-volume centers have been shown to have improved outcomes for pancreatectomy. Regionalization of pancreatic cancer care to high-volume centers has the potential to improve care and outcomes. Practical limitations such as overloading currently available high-volume centers, extending patient travel times, sharing patients within a multipayer health system, and incorporating patient preferences must be addressed for regionalization to become a reality. The benefits and limitations of regionalization of pancreatic cancer care are discussed in this review. To improve the overall quality of pancreatic cancer care at all hospitals in the United States, a combination of referral of patients with pancreatic cancer to high- and moderate-volume hospitals in conjunction with specific quality-improvement efforts at those institutions is proposed.

Pancreatic function testing: here to stay for the 21st century

The diagnosis of Chronic Pancreatitis (CP) is based on the detection of abnormal structure or function of the diseased pancreas. The pancreatic function tests more accurately determine the presence of CP than tests of structure, especially for early stage disease. The function tests can be divided into two categories: non-invasive and invasive. The invasive "tube" tests can reliably detect mild, early CP, but are only available at a few referral centers and tend to be poorly tolerated by patients. The non-invasive tests are easy to obtain, but tend to perform poorly in patients with early, mild disease. Therefore, no one test is useful in all clinical situations, and a detailed understanding of the rational, pathophysiologic basis, strengths, and limitations of various tests is needed. This review highlights the role of various pancreatic function tests in the diagnosis of CP including fecal fat analysis, fecal elastase, fecal chymotrypsin, serum trypsin, the secretin stimulation test, the cholecystokinin (CCK) stimulation test, the combined secretin-CCK stimulation test, the intraductal and endoscopic secretin stimulation tests, and the functional magnetic resonance imaging of the pancreas after secretin stimulation.

Radiologic assessment of acute and chronic pancreatitis

The capabilities of various imaging modalities, including CT, MRI, and ultrasound, have markedly increased over recent years. This has translated into improved detection and improved characterization of various pathologic processes. This article discusses the current role of imaging in the evaluation of acute and chronic pancreatitis. CT remains a major focal point in issues related to acute pancreatitis, whereas MRI (and magnetic resonance cholangiopancreatography) plays a larger role in chronic pancreatitis.

MR cholangiopancreatography in children: feasibility, safety, and initial experience

BACKGROUND

The indications for MR cholangiopancreatography (MRCP) in children, and its safety and findings, might differ from those in adults and are not well described.

OBJECTIVE

To investigate the safety, feasibility, and accuracy of MRCP in children.

MATERIALS AND METHODS

We reviewed all prospective MRCP reports, noting the indication, the use of secretin, endoscopic retrograde cholangiopancreatography (ERCP) findings, and patient outcomes. Two readers reviewed each MRCP study by consensus to rate duct visualization and compare pancreatic duct sizes before and after secretin administration (paired t-test). The likelihood of a normal versus an abnormal MRCP study was compared by gender, pancreatitis as the primary indication, secretin use, and whether ERCP was performed (Fisher's exact test), as well as age (t-test).

RESULTS

A total of 85 MRCP studies were performed in children (mean age 10.3 years), most commonly for evaluation of pancreatitis (n=47, 55%); 41 (48%) used secretin and 39 (46%) used a negative oral contrast agent. Of the 85 studies, 72 (85%) had excellent image quality and 43 were normal. ERCP was performed after 16 of the 85 MRCP studies (19%); the diagnoses were concordant with those of MRCP in 13 (81%). There were 42 abnormal MRCP studies, and these were more likely to be in girls (P=0.03) and in children who had undergone ERCP (P<0.01). Secretin and the negative oral contrast agent were well-tolerated. Secretin improved duct visualization (P<0.001).

CONCLUSION

MRCP safely and accurately depicted pancreaticobiliary anatomy in children. The use of secretin improved visualization of the pancreatic duct.

Disconnection of the pancreatic duct: an important but overlooked complication of severe acute pancreatitis

In patients with severe acute pancreatitis, the percentage of necrosis of pancreatic glandular parenchyma is an important predictor of prognosis. However, little attention has been paid to necrosis of ductal epithelium, which may result in disconnection of the main pancreatic duct. In pancreatic duct disconnection, a viable segment of the pancreatic body or tail is isolated from the gastrointestinal tract; the result is a persistent end fistula, that is, an uncontrolled leak of pancreatic secretions into peripancreatic spaces without communication to the gastrointestinal tract. The authors present their experience with clinical and radiologic follow-up of 85 patients with necrotic pancreatitis who either did (n = 46) or did not (n = 39) have pancreatic duct disconnection at surgery. Confident preoperative diagnosis of a disconnected duct requires both imaging tests (computed tomography or magnetic resonance imaging) and pancreatography. However, not all peripancreatic collections signify ductal disconnection, and imaging has poor accuracy in differentiation between pancreatic and peripancreatic necrosis. Early recognition of disconnected pancreatic duct obviates unnecessary and potentially harmful drainage procedures.