Peripancreatic collections in acute pancreatitis: Correlation between computerized tomography and operative findings

Current trends in acute pancreatitis: Diagnostic and therapeutic challenges

Acute pancreatitis (AP) is an inflammatory disease of the pancreas, which can progress to severe AP, with a high risk of death. It is one of the most complicated and clinically challenging of all disorders affecting the abdomen. The main causes of AP are gallstone migration and alcohol abuse. Other causes are uncommon, controversial and insufficiently explained. The disease is primarily characterized by inappropriate activation of trypsinogen, infiltration of inflammatory cells, and destruction of secretory cells. According to the revised Atlanta classification, severity of the disease is categorized into three levels: Mild, moderately severe and severe, depending upon organ failure and local as well as systemic complications. Various methods have been used for predicting the severity of AP and its outcome, such as clinical evaluation, imaging evaluation and testing of various biochemical markers. However, AP is a very complex disease and despite the fact that there are of several clinical, biochemical and imaging criteria for assessment of severity of AP, it is not an easy task to predict its subsequent course. Therefore, there are existing controversies regarding diagnostic and therapeutic modalities, their effectiveness and complications in the treatment of AP. The main reason being the fact, that the pathophysiologic mechanisms of AP have not been fully elucidated and need to be studied further. In this editorial article, we discuss the efficacy of the existing diagnostic and therapeutic modalities, complications and treatment failure in the management of AP.

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.

Impact of the site of necrosis on outcome of acute pancreatitis

Objecives

To compare the clinical outcome of patients with extrapancreatic necrosis (EXPN) alone with that of acute interstitial pancreatitis (AIP), pancreatic parenchymal necrosis (PPN) alone, and combined PPN and EXPN.

Background

There are only a few studies in the literature in which EXPN has been recently recognized as a subtype of acute necrotizing pancreatitis (ANP), with a better prognosis.

Methods

We analyzed clinical data and outcome variables of 411 consecutive acute pancreatitis (AP) patients between January 2012 and December 2014. Contrast‐enhanced computed tomography (CECT) images of each patient were reviewed and characterized as AIP or ANP. Patients with ANP were divided into EXPN alone, PPN alone, and combined PPN and EXPN. Outcome variables were then compared between these groups.

Results

Of the 411 patients, 74 (18%) had AIP, and 337 (82%) had ANP. Patients with EXPN alone (n = 40; 11.8%) had similar outcomes as patients with PPN alone (n = 12; 3.5%); however, their outcome was worse than that of patients with AIP, with a higher frequency of persistent organ failure (POF), need for percutaneous catheter drainage (PCD), and longer length of hospitalization (LOH). Patients with combined PPN and EXPN (n = 285; 84.7%) had the worst clinical course, with higher frequency of POF, infected necrosis, intervention requirement, and longer LOH.

Conclusion

Patients with combined PPN and EXPN have a severe disease course with the worst clinical outcomes; patients with AIP patients have the most benign course, while patients with EXPN alone stand between the two extremes of disease course with an intermediate grade of severity.

The diagnostic challenge of the sequelae of acute pancreatitis on CT imaging: a pictorial essay

PURPOSE

The purpose of the study was to present a pictorial review of the long-term sequelae of acute pancreatitis on CT imaging as these findings can cause diagnostic confusion in the absence of a proper clinical history and/or prior CT imaging.

METHODS

We retrospectively identified 81 patients who had an episode of acute pancreatitis with diagnostic findings on CT and also underwent one or more follow-up CT scans at least 1 month beyond the acute episode. The residual findings on all follow-up CT scans were tabulated, including the time interval since the initial bout of acute pancreatitis.

RESULT

Residual inflammatory changes were present in 19.8% of cases, with a median time period lasting 86 days since the initial episode of acute pancreatitis. Residual fluid collections were seen in 27.2% and persisted for a median of 132 days. Three patients had residual solid-appearing inflammatory masses, which could be mistaken for neoplasms. Other long-term sequelae were also tabulated, including pancreatic ductal dilatation, pancreatic atrophy, new or increased pancreatic calcifications, biliary tract dilatation, central portal venous occlusion, and pseudoaneurysm formation. These residual findings and long-term complications are presented as a pictorial essay.

CONCLUSION

Recognizing the spectrum of residual findings of acute pancreatitis, some of which can be long term, is important in the correct interpretation of a pancreatic CT. These findings can mimic acute pancreatitis or a pancreatic/peripancreatic neoplasm and often cause diagnostic confusion, especially in the absence of prior CT imaging.

Multidetector CT in emergency radiology: acute and generalized non-traumatic abdominal pain

Multidetector CT (MDCT) is an imaging technique that provides otherwise unobtainable information in the diagnostic work-up of patients presenting with acute abdominal pain. A correct working diagnosis depends essentially on understanding the individual patient's clinical data and laboratory findings. In haemodynamically stable patients with acute severe and generalized abdominal pain, MDCT is now the preferred imaging test and gives invaluable diagnostic information, also in unstable patients after stabilization. In this descriptive review, we focus our attention on acute, severe and generalized or undifferentiated non-traumatic abdominal pain. The main differential diagnoses are acute pancreatitis, gastrointestinal perforation, ruptured abdominal aneurysm and acute mesenteric ischaemia. We will provide radiologist readers with a technical guide to optimize MDCT imaging protocols and list the major CT signs essential to reach a correct diagnosis and guide the best treatment.

Clinical outcomes of combined necrotizing pancreatitis versus extrapancreatic necrosis alone

INTRODUCTION

Extrapancreatic necrosis (EPN) alone, i.e., in the absence of pancreatic parenchyma necrosis has gradually come to be regarded as a separate entity of acute necrotizing pancreatitis (ANP). However, data regarding the prognostic significance of EPN are quite limited, and the outcomes of interventions for patients with EPN alone are not well elucidated. The aim of this study was to explore the differences in the outcomes of patients with EPN alone and patients with both the pancreatic parenchyma and extrapancreatic necrosis (combined necrosis).

METHODS

From January 2009 to December 2013, a total of 334 patients with ANP who had received interventions in the West China Hospital in China were included. Based on the extent of necrosis as assessed with contrast-enhanced CT, the patients were divided into Group 1 (n = 285) in which the necrosis involved both the pancreatic parenchyma and extrapancreatic tissues (combined necrosis) and Group 2 (n = 49) in which the necrosis involved only the extrapancreatic tissues. Additionally, Group 3 included 443 patients with interstitial pancreatitis who were also included in the analyses. The demographic characteristics, support treatment information, organ failure information, infection necrosis, persistent systemic inflammatory response syndrome (SIRS) in the first week of onset, CT severity index, and intervention types, as well as the postoperative stay lengths, ICU utility, and complications were collected and compared.

RESULTS

Compared with the patients in Group 1, the patients in Group 2 suffered less persistent SIRS in the first week of onset (12/24.5% vs. 145/50.9%; P < 0.05), less persistent organ failure (6/12.2% vs. 95/33.3%; P < 0.05), less persistent multiple organ failure (3/6.1% vs. 67/23.5%; P < 0.05), and less bacteremia (5/10.2% vs. 107/37.5%; P < 0.001). The intervention types were significantly different between the two groups (P < 0.001); initial open necrosectomy was performed in 174/61.6% and 8/16.3% of the patients in Groups 1 and 2, respectively, and initial percutaneous catheter drainage (PCD) was performed in 73/25.6% and 29/59.2% of the patients in the two respective groups. Second open necrosectomies following PCD were required in 61/83.5% and 9/31.0% of the patients in Groups 1 and 2, respectively (P < 0.001). A greater number of patients in Group 1 were diagnosed with infected necrosis (204/71.6% vs. 10/20.4%; P < 0.001) and had to be sent to the ICU for further postoperative care (221/77.5% vs. 23/46.9%; P < 0.001). The postoperative stay was longer for Group 1 (median: 43.0 vs. 26.5 days; P < 0.001). Residual necrotic tissue or abscess was the most common postoperative complication in both groups. The mortality was higher in Group 1 (52/18.2% vs. 1/2.1%; P < 0.05). Compared with the patients in Group 2, the patients with interstitial pancreatitis exhibited milder courses and better outcomes. Subgroup comparisons with Group 1 indicated that early multiple organ failure was significantly associated with higher mortality.

CONCLUSION

The patients with EPN alone exhibited significantly better prognoses than those with combined necrosis, and EPN alone should be regarded as a separate group of acute necrotizing pancreatitis. Open necrosectomy can be avoided in the majority of patients with EPN alone, who receive PCD as the initial first intervention.

Imaging of Acute Pancreatitis

Acute pancreatitis is an acute inflammation of the pancreas. Several classification systems have been used in the past but were considered unsatisfactory. A revised Atlanta classification of acute pancreatitis was published that assessed the clinical course and severity of disease; divided acute pancreatitis into interstitial edematous pancreatitis and necrotizing pancreatitis; discerned an early phase (first week) from a late phase (after the first week); and focused on systemic inflammatory response syndrome and organ failure. This article focuses on the revised classification of acute pancreatitis, with emphasis on imaging features, particularly on newly-termed fluid collections and implications for the radiologist.

Consensus guidelines on severe acute pancreatitis

This Position Paper contains clinically oriented guidelines by the Italian Association for the Study of the Pancreas (AISP) for the diagnosis and treatment of severe acute pancreatitis. The statements were formulated by three working groups of experts who searched and analysed the most recent literature; a consensus process was then performed using a modified Delphi procedure. The statements provide recommendations on the most appropriate definition of the complications of severe acute pancreatitis, the diagnostic approach and the timing of conservative as well as interventional endoscopic, radiological and surgical treatments.

Treatment of severe acute pancreatitis and its complications

Severe acute pancreatitis (SAP), which is the most serious type of this disorder, is associated with high morbidity and mortality. SAP runs a biphasic course. During the first 1-2 wk, a pro-inflammatory response results in systemic inflammatory response syndrome (SIRS). If the SIRS is severe, it can lead to early multisystem organ failure (MOF). After the first 1-2 wk, a transition from a pro-inflammatory response to an anti-inflammatory response occurs; during this transition, the patient is at risk for intestinal flora translocation and the development of secondary infection of the necrotic tissue, which can result in sepsis and late MOF. Many recommendations have been made regarding SAP management and its complications. However, despite the reduction in overall mortality in the last decade, SAP is still associated with high mortality. In the majority of cases, sterile necrosis should be managed conservatively, whereas in infected necrotizing pancreatitis, the infected non-vital solid tissue should be removed to control the sepsis. Intervention should be delayed for as long as possible to allow better demarcation and liquefaction of the necrosis. Currently, the step-up approach (delay, drain, and debride) may be considered as the reference standard intervention for this disorder.

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.

Extrapancreatic necrosis without pancreatic parenchymal necrosis: a separate entity in necrotising pancreatitis?

OBJECTIVE

In the revised Atlanta classification of acute pancreatitis, the term necrotising pancreatitis also refers to patients with only extrapancreatic fat necrosis without pancreatic parenchymal necrosis (EXPN), as determined on contrast-enhanced CT (CECT). Patients with EXPN are thought to have a better clinical outcome, although robust data are lacking.

METHODS

A post hoc analysis was performed of a prospective multicentre database including 639 patients with necrotising pancreatitis on contrast-enhanced CT. All CECT scans were reviewed by a single radiologist blinded to the clinical outcome. Patients with EXPN were compared with patients with pancreatic parenchymal necrosis (with or without extrapancreatic necrosis). Outcomes were persistent organ failure, need for intervention and mortality. A predefined subgroup analysis was performed on patients who developed infected necrosis.

RESULTS

315 patients with EXPN were compared with 324 patients with pancreatic parenchymal necrosis. Patients with EXPN less often suffered from complications: persistent organ failure (21% vs 45%, p<0.001), persistent multiple organ failure (15% vs 36%, p<0.001), infected necrosis (16% vs 47%, p<0.001), intervention (18% vs 57%, p<0.001) and mortality (9% vs 20%, p<0.001). When infection of extrapancreatic necrosis developed, outcomes between groups were equal (mortality with infected necrosis: EXPN 28% vs pancreatic necrosis 18%, p=0.16).

CONCLUSION

EXPN causes fewer complications than pancreatic parenchymal necrosis. It should therefore be considered a separate entity in acute pancreatitis. Outcome in cases of infected necrosis is similar.

Early detection of low enhanced pancreatic parenchyma by contrast-enhanced computed tomography predicts poor prognosis of patients with acute pancreatitis

OBJECTIVES

The usefulness of early severity assessment of acute pancreatitis (AP) by contrast-enhanced computed tomography (CECT) was investigated.

METHODS

Data were obtained from a 2007 nationwide survey in Japan. Clinical data of 983 patients with AP were analyzed. All were examined by CECT on the day of admission.

RESULTS

Early findings of CECT demonstrated that low enhanced pancreatic parenchyma (LEPP) was associated with the incidence of organ failure (OF), multiple OF, and infectious complications as well as mortality (P < 0.0001). Next, patients were further divided into 4 groups according to the CECT findings, which focused on the LEPP and peripancreatic collections (PPCs). The LEPP/PPC (+/+) group was characterized as high morbidity and high mortality. The incidence of OF (28.2%), multiple OF (15.5%), and mortality (11.4%) in patients assigned to the (+/+) group was significantly higher than in those assigned to the other groups. The incidence of infectious complications was significantly higher in patients assigned to the (+/+) group (16.7%), the (+/-) group (9.0%), and the (-/+) group (7.0%) than those assigned to the (-/-) group (1.8%).

CONCLUSIONS

The detection of LEPP and PPC was a useful CECT finding for the early assessment of the severity of AP.

Global survey of controversies in classifying the severity of acute pancreatitis

BACKGROUND

The need to accurately classify the severity of patients with acute pancreatitis is widely acknowledged but some questions pertinent to this remain debatable. The aim of this study was to benchmark opinions of pancreatologists worldwide with regard to the issues related to classifying the severity of acute pancreatitis.

METHODS

An online survey was conducted using an independent commercial service. The corresponding authors of all articles pertinent to clinical aspects of acute pancreatitis published over the last 5 years were invited to participate.

RESULTS

A total of 528 invitations were sent and 240 (45%) responses from 49 countries, representing all the inhabited continents, were received. The Atlanta approach to classifying the severity of acute pancreatitis was considered adequate for modern clinical practice and clinical research by 40 (17%) of the respondents. The determinants-based approach to classifying the severity of acute pancreatitis was considered adequate for modern clinical practice and clinical research by 188 (78%) and 191 (80%) of the respondents, respectively. The definitions of local and systemic determinants of severity were also clarified.

CONCLUSION

Classifying the severity of acute pancreatitis on the basis of Atlanta approach was considered inadequate by the overwhelming majority of respondents. An international consensus on the new classification of severity of acute pancreatitis has to take into account the results of this survey.

The revised Atlanta classification of acute pancreatitis: its importance for the radiologist and its effect on treatment

An international working group has modified the Atlanta classification for acute pancreatitis to update the terminology and provide simple functional clinical and morphologic classifications. The modifications (a) address the clinical course and severity of disease, (b) divide acute pancreatitis into interstitial edematous pancreatitis and necrotizing pancreatitis, (c) distinguish an early phase (1st week) and a late phase (after the 1st week), and (d) emphasize systemic inflammatory response syndrome and multisystem organ failure. In the 1st week, only clinical parameters are important for treatment planning. After the 1st week, morphologic criteria defined on the basis of computed tomographic findings are combined with clinical parameters to help determine care. This revised classification introduces new terminology for pancreatic fluid collections. Depending on presence or absence of necrosis, acute collections in the first 4 weeks are called acute necrotic collections or acute peripancreatic fluid collections. Once an enhancing capsule develops, persistent acute peripancreatic fluid collections are referred to as pseudocysts; and acute necrotic collections, as walled-off necroses. All can be sterile or infected. Terms such as pancreatic abscess and intrapancreatic pseudocyst have been abandoned. The goal is for radiologists, gastroenterologists, surgeons, and pathologists to use the revised classifications to standardize imaging terminology to facilitate treatment planning and enable precise comparison of results among different departments and institutions.

Early management of severe acute pancreatitis

Significant literature on the management of acute severe acute pancreatitis has emerged in recent years. The new information ranges from data on newer single or multiparameter severity assessment tools and classification systems to therapeutic modalities. However, a few basic issues-the ideal severity assessment modality, volume of intravenous fluids required in the first 48 to 72 h, and the role of prophylactic antibiotics-are still not clear and are subject to controversy. The International Working Group has devised the Revised Atlanta Classification, which will be published soon. This new classification is eagerly awaited worldwide, and hopefully clarifies many of the problems of the original Atlanta Classification. In this article, we discuss the developments that have arisen in the past 2 to 3 years concerning the classification, prognostication, and early management of severe acute pancreatitis.

Comments on the article about correlation between computerized tomography and surgery in acute pancreatitis

We read with great interest the article by Vege et al published in issue 34 of World J Gastroenterol 2010. The article evaluates the ability of contrast-enhanced computerized tomography (CECT) to characterize the nature of peripancreatic collections found at surgery. The results of their study indicate that most of the peripancreatic collections seen on CECT in patients with severe acute pancreatitis who require operative intervention contain necrotic tissue and CECT has a limited role in differentiating various types of collections. However, there are some points that need to be addressed, including data about the stage of acute pancreatitis in which CECT was done and the time span between CECT examination and surgery.

Progress in the management of necrotizing pancreatitis

Pancreatic necrosis, a complication of severe pancreatitis, may become infected, resulting in significant morbidity and potential mortality. Infected necrosis was heretofore considered a surgical condition, and despite aggressive operative management, the mortality remained high. With a better understanding of the natural history of necrosis, established methods to diagnose infection and the increasing use of minimally invasive techniques, less aggressive therapies have been utilized with some success. The present study evaluated a step-up approach for the treatment of infected pancreatic necrosis, utilizing endoscopic and percutaneous techniques, and if ineffective, necrosectomy with a minimally invasive retroperitoneal approach. They compared this step-up approach to the standard open necrosectomy. They demonstrated that when using such an approach compared with open necrosectomy, the frequency of major complications such as organ failure, perforation, fistula or even death was significantly less than in those who received conventional open necrosectomy. Indeed, for those randomized to the step-up approach, roughly a third of the patients were successfully treated with percutaneous drainage alone. In the long-term, development of diabetes was also less frequent in those receiving less aggressive therapy. These findings, in combination with other reports, suggest that the dogma that open necrosectomy is mandatory for all patients with infected necrosis should be re-evaluated, and that less aggressive treatments as part of a multidisciplinary approach can reduce morbidity and mortality.