Pancreatic fluid collections prior to intervention: evaluation with MR imaging compared with CT and US

Acute pancreatitis and computed tomography: Interest of portal venous phase alone in the initial phase

BACKGROUND

There are no guidelines in the literature for the use of a computed tomography (CT) protocol in the initial phase of acute pancreatitis (AP).

PURPOSE

To evaluate the contribution of single portal venous phase CT compared to triple-phase CT protocol, performed in the initial phase of AP for severity assessment.

MATERIAL AND METHODS

In this retrospective study, a total of 175 patients with acute pancreatitis who underwent initial triple-phase CT protocol (non-contrast, arterial phase, and portal venous phase) between D3 and D7 after the onset of symptoms were included. Analysis of AP severity and complications was independently assessed by two readers using three validated CT severity scores (CTSI, mCTSI, EPIC). All scores were applied to the triple-phase CT protocol and compared to the single portal venous phase. Inter-observer analyses were also performed.

RESULTS

No significant difference whatever the severity score was observed after analysis of the single portal venous phase compared with the triple-phase CT protocol (interstitial edematous pancreatitis: CTSI: 2 vs. 2, mCTSI: 2 vs. 2, EPIC: 1 vs. 1; necrotizing pancreatitis: CTSI: 6 vs. 6, mCTSI: 8 vs. 8, EPIC: 5 vs. 5). Inter-observer agreement was excellent (ICC = 0.96-0.99), whatever the severity score.

CONCLUSION

A triple-phase CT protocol performed at the initial phase of AP was no better than a single portal venous for assessing the severity of complications and could lead to a 63% reduction in irradiation.

Magnetic resonance imaging in the evaluation and management of acute pancreatitis: a review of current practices and future directions

Acute pancreatitis is a condition marked by inflammation of the pancreas and surrounding tissues. While the majority of cases of acute pancreatitis are mild, a minority of severe cases are the primary contributors to the morbidity and mortality attributed to this condition. Retroperitoneal morphologic changes can be detected by utilization of various imaging modalities, and their accurate evaluation is crucial for effective management. Acute pancreatitis is commonly diagnosed using computed tomography (CT). However, there are certain clinical scenarios where magnetic resonance imaging (MRI) may have superiority over CT. In particular, MRI is useful in cases where patients cannot receive iodinated CT contrast, or where there is a need to investigate the underlying cause of acute pancreatitis. Additionally, MRI can be utilized to evaluate ductal disconnection and guide interventions for necrotic collections. The unique features of MRI can be particularly useful, including its ability to provide superior contrast resolution and to offer greater functional information through techniques such as diffusion-weighted imaging. The aim of this review is to discuss the MRI assessment of individuals with acute pancreatitis. Additionally, the recent advances in MRI for evaluation of acute pancreatitis will also be introduced.

Endoscopic Ultrasound Guided Walled-off Necrosis Drainage

Walled-off necrosis is a well-recognized complication of necrotizing pancreatitis that can cause sepsis, luminal or ductal obstruction, or persistent unwellness requiring multidisciplinary care. Recent data suggest that minimally invasive endoscopic treatment strategies are preferred over more invasive surgical approaches. Although endoscopic transmural drainage with or without necrosectomy is the primary approach for patients requiring an intervention, for collections not amenable to endoscopic approach, percutaneous drain placement followed by video-assisted retroperitoneal debridement or laparoscopic cystogastrostomy with internal debridement are other alternatives. More studies are required to optimize post-procedure care to shorten the length of stay and minimize resource utilization.

Computed tomography imaging-based predictors of the need for a step-up approach after initial endoscopic ultrasound-guided transmural drainage for pancreatic fluid collections

BACKGROUND

A step-up approach is recommended as a new treatment algorithm for pancreatic fluid collections (PFCs). However, determining which patients with PFCs require a step-up approach after endoscopic ultrasound-guided transmural drainage (EUS-TD) is unclear. If the need for a step-up approach could be predicted, it could be performed early for relevant patients. We aimed to identify PFC-related predictive factors for a step-up approach after EUS-TD.

METHODS

This retrospective cohort study included consecutive patients who had undergone EUS-TD for PFCs from January 2008 to May 2020. Multivariable logistic regression analyses were performed to investigate PFC factors related to requiring a step-up approach. A step-up approach was performed for patients who did not respond clinically to EUS-TD.

RESULTS

We enrolled 81 patients, of whom 25 (30.9%) required a step-up approach. In multivariate logistic regression analysis, the pre-EUS-TD number of PFC-occupied regions ≥ 3 (multivariate odds ratio [OR] 16.2, 95% confidence interval [CI] 2.68-97.6, P = 0.002), the post-EUS-TD PFC-remaining percentage ≥ 35% (multivariate OR 19.9, 95% CI 2.91-136.1, P = 0.002), and a positive sponge sign, which is a distinctive computed tomography finding in the early stage after EUS-TD (multivariate OR 6.26, 95% CI 1.33-29.3, P = 0.020), were independent predictive factors associated with requiring a step-up approach for PFCs.

CONCLUSION

Pre-EUS-TD PFC-occupied regions, post-EUS-TD PFC-remaining percentage, and a positive sponge sign were predictors of the need for a step-up approach. Patients with PFC with these findings should be offered a step-up approach whereas conservative treatment is recommended for patients without these findings.

CLINICAL REGISTRATION NUMBER

UMIN 000030898.

EUS-guided drainage of large walled-off pancreatic necroses using plastic versus lumen-apposing metal stents: a single-centre randomised controlled trial

OBJECTIVE

In treating pancreatic walled-off necrosis (WON), lumen-apposing metal stents (LAMS) have not proven superior to the traditional double pigtail technique (DPT). Among patients with large WON (>15 cm) and their associated substantial risk of treatment failure, the increased drainage capacity of a novel 20-mm LAMS might improve clinical outcomes. Hence, we conducted a study comparing the DPT and 20-mm LAMS in patients with large WON.

DESIGN

A single-centre, open-label, randomised, controlled superiority trial using an endoscopic step-up approach in patients with WON exceeding 15 cm in size. The primary endpoint was the number of necrosectomies needed to achieve clinical success (clinical and CT resolution), while the secondary endpoints included technical success, adverse events, length of stay and mortality.

RESULTS

Twenty-two patients were included in the DPT group and 20 in the LAMS group, with no significant differences in patient characteristics. The median size of WON was 24.1 cm (P25-P75: 19.6-31.1). The technical success rates were 100% for DPT and 95% for LAMS (p=0.48), while clinical success rates were 95.5% and 94.7%, respectively (p=1.0). The mean number of necrosectomies was 2.2 for DPT and 3.2 for LAMS (p=0.42). Five patients (12%) developed procedure-related serious adverse events (DPT=4, LAMS=1, p=0.35). The median length of stay was 43 (P25-P75: 40-67) and 58 days (P25-P75: 40-86) in the DPT and LAMS groups (p=0.71), respectively, with an overall mortality of 4.8%.

CONCLUSIONS

For treating large WON, LAMS are not superior to DPT. The techniques are associated with comparable needs for necrosectomy and hospital stay, and no gross difference in adverse events.

TRIAL REGISTRATION NUMBER

NCT04057846.

Abbreviated non-enhanced magnetic resonance imaging in patients with acute necrotizing pancreatitis

AIM

To investigate the performance of T2-weighted abbreviated magnetic resonance imaging (T2W-AMRI) protocol in evaluating patients with acute necrotizing pancreatitis (ANP).

METHODS

A retrospective analysis of consecutive hospitalized patients with ANP who underwent MRI (contrast-enhanced, CE or non-contrast, NC) between January 2017 and November 2020 was performed. The T2W-AMRI and complete MRI (cMRI) sequences were anonymized, and subsequently, two separate sets of data (AMRI and cMRI) were created for presentation to the radiologists involved in reading the data. The T2W-AMRI was based on a single-axial T2 half-Fourier acquisition single-shot turbo spin-echo (HASTE) sequence. The pancreatic and extrapancreatic findings were recorded and tabulated independently by two radiologists on T2W-AMRI and cMRI. In addition, the interobserver agreement and association of findings between T2W-AMRI and cMRI were analyzed.

RESULTS

Twenty-eight patients (mean age 31.7 ± 12.2 years, 17 females) were included. Thirteen patients had CE-cMRI, while the rest underwent NC-cMRI. There was no significant difference in the identification of pancreatic necrosis on T2W-AMRI vs. cMRI (p = 1.00). However, T2W-AMRI underestimated necrosis in one patient. Collections were accurately detected in all patients on T2W-AMRI. The mean size of the collection was larger on cMRI (6.5 ± 3.7 cm) than T2W-AMRI (6 ± 3.7 cm) with p = 0.006. cMRI detected more patients with disrupted pancreatic duct (n = 9) than T2W-AMRI (n = 6). However, the difference was not statistically significant (p = 0.375). There was a good to an excellent interobserver agreement between the readers for T2W-AMRI (k = 0.62-1).

CONCLUSION

T2W-AMRI may offer a suitable alternative to cMRI in ANP, especially severe disease, as it can be acquired rapidly without the need for contrast injection.

The endoscopic ultrasound features of pancreatic fluid collections and their impact on therapeutic decisions: an interobserver agreement study

BACKGROUND

A validated classification of endoscopic ultrasound (EUS) morphological characteristics and consequent therapeutic intervention(s) in pancreatic and peripancreatic fluid collections (PFCs) is lacking. We performed an interobserver agreement study among expert endosonographers assessing EUS-related PFC features and the therapeutic approaches used.

METHODS

50 EUS videos of PFCs were independently reviewed by 12 experts and evaluated for PFC type, percentage solid component, presence of infection, recognition of and communication with the main pancreatic duct (MPD), stent choice for drainage, and direct endoscopic necrosectomy (DEN) performance and timing. The Gwet's AC1 coefficient was used to assess interobserver agreement.

RESULTS

A moderate agreement was found for lesion type (AC1, 0.59), presence of infection (AC1, 0.41), and need for DEN (AC1, 0.50), while fair or poor agreements were stated for percentage solid component (AC1, 0.15) and MPD recognition (AC1, 0.31). Substantial agreement was rated for ability to assess PFC-MPD communication (AC1, 0.69), decision between placing a plastic versus lumen-apposing metal stent (AC1, 0.62), and timing of DEN (AC1, 0.75).

CONCLUSIONS

Interobserver agreement between expert endosonographers regarding morphological features of PFCs appeared suboptimal, while decisions on therapeutic approaches seemed more homogeneous. Studies to achieve standardization of the diagnostic endosonographic criteria and therapeutic approaches to PFCs are warranted.

Radiologic Predictors of Increased Number of Necrosectomies During Endoscopic Management of Walled-off Pancreatic Necrosis

GOALS

No established methods exist to predict who will require a higher number of endoscopic necrosectomy sessions for walled-off necrosis (WON). We aim to identify radiologic predictors for requiring a greater number of necrosectomy sessions. This may help to identify patients who benefit from aggressive endoscopic management.

MATERIALS AND METHODS

This is a multicenter retrospective study of patients with WON at 3 tertiary care centers. WON characteristics on preintervention computed tomography imaging were evaluated to determine if they were predictive of requiring more endoscopic necrosectomy.

RESULTS

A total of 104 patients were included. Seventy patients (67.3%) underwent endoscopic necrosectomy, with median of 2 necrosectomies. WON largest transverse diameters (P=0.02), largest coronal diameters (P=0.01), necrosis pattern [likelihood ratio (LR)=17.85, P<0.001], spread (LR=11.02, P=0.01), hemorrhage (LR=8.64, P=0.003), and presence of disconnected pancreatic duct (LR=6.80, P=0.01) were associated with undergoing ≥2 necrosectomies. Patients with septations/loculations were significantly less likely to undergo ≥2 necrosectomies (LR=4.86, P=0.03).

CONCLUSIONS

Several computed tomography radiologic features were significantly associated with undergoing ≥2 necrosectomies. These could help identify patients who will undergo a higher number of endoscopic necrosectomy sessions.

JPN clinical practice guidelines 2021 with easy-to-understand explanations for the management of acute pancreatitis

BACKGROUND

In preparing the Japanese (JPN) guidelines for the management of acute pancreatitis 2021, the committee focused the issues raised by the results of nationwide epidemiological survey in 2016 in Japan METHOD: In addition to a systematic search using the previous JPN guidelines, papers published from January 2014 to September 2019 were searched for the contents to be covered by the guidelines based on the concept of GRADE system.

RESULTS

Thirty-six clinical questions (CQ) were prepared in 15 subject areas. Base on the facts that patients diagnosed with severe disease by both Japanese prognostic factor score and contrast-enhanced CT grade had a high fatality rate and that little prognosis improvement after 2 weeks of disease onset was not obtained, we emphasized the importance of Pancreatitis Bundles, which was shown to be effective in improving prognosis, and the CQ sections for local pancreatic complications had been expanded to ensure adoption of a step-up approach. Furthermore, on the facts that enteral nutrition for severe acute pancreatitis was not started early within 48 hours of admission and that unnecessary prophylactic antibiotics was used in almost all cases, we emphasized early enteral nutrition in small amounts even if gastric feeding is used and no prophylactic antibiotics in mild pancreatitis.

CONCLUSION

All the members of the committee have put a lot of effort into preparing the extensively revised guidelines in the hope that more people will have a common understanding and that better medical care will be spread.

Hemosuccus Pancreaticus: A Comprehensive Review of Presentation Patterns, Diagnostic Approaches, Therapeutic Strategies, and Clinical Outcomes

Hemosuccus pancreaticus is a rare but potentially torrential and life-threatening cause of acute upper gastrointestinal bleeding. It is described as an intermittent hemorrhage from the major duodenal papilla via the main pancreatic duct. Peripancreatic pseudoaneurysm following chronic pancreatitis is a common underlying etiology. However, gastroduodenal artery pseudoaneurysm-related hemosuccus pancreaticus remains exceedingly rare in the etiological spectrum of upper gastrointestinal bleeding. We hereby delineate a rare case of hemosuccus pancreaticus associated with gastroduodenal artery pseudoaneurysm in a patient who initially presented with abdominal pain and hematochezia. He was successfully managed with coil embolization without recurrence or sequelae. Furthermore, we conducted a search of the MEDLINE (PubMed and Ovid) database for relevant studies on hemosuccus pancreaticus published between inception and September 15, 2021. The available clinical evidence on causes, presentation patterns, diagnosis, and management was analyzed and summarized. This article highlights the rarity, the intermittent nature of hemorrhage, and the lack of a standardized diagnostic approach for this elusive disease. Clinicians should remain cognizant of hemosuccus pancreaticus, especially in patients presenting with symptoms and signs of intermittent gastrointestinal bleeding and abdominal pain. Prompt diagnosis carries paramount importance in saving patients from repeat hospital admissions and disease-associated morbidity and mortality. Conventional angiography with coil embolization may constitute an effective treatment strategy.

A preferable modality for the differentiation of peripancreatic fluid collections: Endoscopic ultrasound

Background and Objectives:

Peripancreatic fluid collections (PFCs), including walled-off necrosis (WON) and pancreatic pseudocysts (PPCs), are categorized by imaging modalities, including EUS, computed tomography (CT), and magnetic resonance imaging. Our study aimed to evaluate the effectiveness of EUS in differentiating PFCs compared with that of other modalities.

Subjects and Methods:

Data were collected retrospectively from 99 patients at fourteen centers who were recruited to undergo lumen-apposing metal stent placement to treat PFCs.

Results:

PFCs were detected by CT and EUS in 51 WON and 48 PPC patients. The accuracy in differentiating PFCs by EUS was much higher than that of CT (90.9% vs. 50.5%, P < 0.001). The accuracy in identifying WON on EUS was much higher than that on CT (82.4% vs. 13.7%, P < 0.001), while the accuracy in identifying PPC was comparable in these two modalities (89.6% vs. 100%, P > 0.05). WON patients required more times of debridement than PPC patients (P < 0.001).

Conclusion:

EUS can categorize symptomatic PFCs with higher accuracy than CT and is a preferred imaging modality to detect solid necrotic debris.

Percutaneous biopsy and drainage of the pancreas

Percutaneous pancreatic interventions performed by abdominal radiologists play important diagnostic and therapeutic roles in the management of a wide range of pancreatic pathology. While often performed with endoscopy, pancreatic mass biopsy obtained via a percutaneous approach may serve as the only feasible option for diagnosis in patients with post-surgical anatomy, severe cardiopulmonary conditions, or prior non-diagnostic endoscopic attempts. Biopsy of pancreatic transplants are commonly performed percutaneously due to inaccessible location of the allograft by endoscopy, usually in the right lower quadrant or pelvis. Percutaneous drainage of collections in acute pancreatitis is primarily indicated for infection with clinical deterioration and may be performed alone or in combination with endoscopic drainage. Post-surgical pancreatic collections related to pancreatic duct fistula or leak also often warrant therapeutic percutaneous drainage. Knowledge of appropriate indications, strategies of approach, technique, and complications associated with these procedures is critical for a successful clinical practice.

[Imaging diagnostics in acute pancreatitis]

Abdominal imaging is an important component of the diagnostics of acute pancreatitis. In addition to the clinical features and the laboratory constellation, it serves to establish the diagnosis or the exclusion of other diseases and also the identification and assessment of the course of local complications and vascular changes that can arise during the course of acute pancreatitis. Due to the numerous imaging examination methods that are available, their combination options and the different examination times, there are diverse application options that have to be taken into account, such as the severity and duration of the disease, concomitant diseases and complications of acute pancreatitis. A rational use of imaging is an important prerequisite for high quality and at the same time cost-effective patient care. This review summarizes the current importance of imaging in acute pancreatitis, with particular reference to the updated S3 guidelines on acute pancreatitis.

Clinical Practice Guidelines for the Endoscopic Management of Peripancreatic Fluid Collections

Endoscopic ultrasonography-guided intervention has gradually become a standard treatment for peripancreatic fluid collections (PFCs). However, it is difficult to popularize the procedure in Korea because of restrictions on insurance claims regarding the use of endoscopic accessories, as well as the lack of standardized Korean clinical practice guidelines. The Korean Society of Gastrointestinal Endoscopy (KSGE) appointed a Task Force to develope medical guidelines by referring to the manual for clinical practice guidelines development prepared by the National Evidence-Based Healthcare Collaborating Agency. Previous studies on PFCs were searched, and certain studies were selected with the help of experts. Then, a set of key questions was selected, and treatment guidelines were systematically reviewed. Answers to these questions and recommendations were selected via peer review. This guideline discusses endoscopic management of PFCs and makes recommendations on Indications for the procedure, pre-procedural preparations, optimal approach for drainage, procedural considerations (e.g., types of stent, advantages and disadvantages of plastic and metal stents, and accessories), adverse events of endoscopic intervention, and procedural quality issues. This guideline was reviewed by external experts and suggests best practices recommended based on the evidence available at the time of preparation. This will be revised as necessary to address advances and changes in technology and evidence obtained in clinical practice and future studies.

Clinical Practice Guidelines for the Endoscopic Management of Peripancreatic Fluid Collections

Endoscopic ultrasonography-guided intervention has gradually become a standard treatment for peripancreatic fluid collections (PFCs). However, it is difficult to popularize the procedure in Korea because of restrictions on insurance claims regarding the use of endoscopic accessories, as well as the lack of standardized Korean clinical practice guidelines. The Korean Society of Gastrointestinal Endoscopy appointed a Task Force to develop medical guidelines by referring to the manual for clinical practice guidelines development prepared by the National Evidence-Based Healthcare Collaborating Agency. Previous studies on PFCs were searched, and certain studies were selected with the help of experts. Then, a set of key questions was selected, and treatment guidelines were systematically reviewed. Answers to these questions and recommendations were selected via peer review. This guideline discusses endoscopic management of PFCs and makes recommendations on Indications for the procedure, pre-procedural preparations, optimal approach for drainage, procedural considerations (e.g., types of stent, advantages and disadvantages of plastic and metal stents, and accessories), adverse events of endoscopic intervention, and procedural quality issues. This guideline was reviewed by external experts and suggests best practices recommended based on the evidence available at the time of preparation. This will be revised as necessary to address advances and changes in technology and evidence obtained in clinical practice and future studies. (Gut Liver 2021;15:-693)

Role of endoscopic ultrasonography in the management of peripancreatic collections. Diagnostic and therapeutic approach

Pancreatic fluid collections are surrounded by a wall of granulation tissue and may contain necrotic debris. They occur following a severe acute pancreatitis and most of the cases resolve spontaneously after several weeks. However, their management may lead to a very hardto-treat condition, requiring a multidisciplinary approach. During the last decades we assisted to a change of paradigm involving Endoscopic Ultrasonography, from a pure diagnostic technique to an interventional-therapeutic one, allowing an effective, safe and less invasive approach than other existing treatment standards, historically consisting of surgical and percutaneous drainage. Treatment of pancreatic fluid collections is indicated if they become infected or symptomatic. Over the past years, exponential developments were done in interventional endoscopic approach, making it the first line suggested modality. The use of endoscopic ultrasound allows assessment of the collection, even when it is not directly bulging on gastrointestinal wall, creation of an internal fistulous tract, checking for surrounding vessels with the use of Doppler, and deployment of a stent avoiding the discomfort of external tubes. Several types of stent have been used for endoscopic drainage: plastic double pigtail stents, fully covered self-expanding metal stents and, more recently, lumen apposing metal stents, which are considered revolutionary because of their two-side flanges and wide and short internal channel, a new design that made easier direct endoscopic necrosectomy. This review aims to go through currently available literature on the diagnostic and therapeutic role of Endoscopic Ultrasonography to handle pancreatic fluid collections.

North American Society for Pediatric Gastroenterology, Hepatology and Nutrition and the Society for Pediatric Radiology Joint Position Paper on Noninvasive Imaging of Pediatric Pancreatitis: Literature Summary and Recommendations

ABSTRACT

The reported incidence of pediatric pancreatitis is increasing. Noninvasive imaging, including ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI), play important roles in the diagnosis, staging, follow-up, and management of pancreatitis in children. In this position paper, generated by members of the Pancreas Committee of the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition (NASPGHAN) and the Abdominal Imaging Committee of The Society for Pediatric Radiology (SPR), we review the roles of noninvasive imaging in pediatric acute, acute recurrent, and chronic pancreatitis. We discuss available evidence related to noninvasive imaging, highlighting evidence specific to pediatric populations, and we make joint recommendations for use of noninvasive imaging. Further, we highlight the need for research to define the performance and role of noninvasive imaging in pediatric pancreatitis.

Imaging guidelines for acute pancreatitis: when and when not to image

In patients with acute pancreatitis (AP), diagnostic imaging is performed for various reasons, including the detection of the etiology (e.g., biliary obstruction caused by gallstones), diagnosis of pancreatitis in an unclear clinical setting, assessment of the severity of the process, and evaluation of its complications. In spite of the potential benefits of these imaging studies in the setting of AP, especially economic consequences but also medical risks are associated with diagnostic imaging, including increase of the effective radiation dose received by patients with AP and rising health care costs, frequently without impact on management. The rising incidence of acute pancreatitis in the Western world is escalating its financial burden with national health care expenses of over 2.5 billion dollars annually. Despite evidence-based national recommendations on utilization of diagnostic imaging in patients with AP, unnecessary imaging studies are still frequently performed, especially in the early hospital course. The purpose of this article is, therefore, to review the imaging guidelines for acute pancreatitis with regards to when and when not to image, with the aim to minimize inappropriate utilization.

Pancreatic fluid collections: Clinical manifestations, diagnostic evaluation and management

Pancreatic fluid collections (PFC), including pancreatic pseudocysts and walled-off pancreatic necrosis, are a known complication of severe acute pancreatitis. A majority of the PFCs remain asymptomatic and resolve spontaneously. However, some PFCs persist and can become symptomatic. Persistent PFCs can also cause further complications such as the gastric outlet, intestinal, or biliary obstruction and infection. Surgical interventions are indicated for the drainage of symptomatic sterile and infected PFCs. Management of PFCs has evolved from a primarily surgical or percutaneous approach to a less invasive endoscopic approach. Endoscopic interventions are associated with improved outcomes with lesser chances of complications, faster recovery time, and lower healthcare utilization. Endoscopic ultrasound-guided drainage of PFCs using lumen-apposing metal stents has become the preferred approach for the management of symptomatic and complicated PFCs.

The characteristics of acute necrotizing pancreatitis in different age stages: An MRI study

PURPOSE

To study the characteristics of acute necrotizing pancreatitis (ANP) in different age stages and their correlations with the clinical outcomes using magnetic resonance imaging (MRI).

METHOD

MRI of 716 patients with acute pancreatitis was retrospectively reviewed to assess the incidence and characteristics of ANP. On MRI, ANP was classified into three subtypes: extrapancreatic necrosis (EPN) alone, pancreatic necrosis (PN) alone and combined necrosis. The extent of necrosis was also quantified on MRI. All patients were divided into three age groups, that is, young,middle-aged and elderly groups, and these characteristics of ANP were compared among the three age groups. The endpoints of patients' clinical outcome were compared among different age groups and different characteristics of ANP.

RESULTS

Of the 716 patients, 129(18 %) were identified as ANP on MRI. The prevalence of ANP in the elderly group was the highest (28.9 %, p < 0.05). The patients in the middle-age and the elderly groups exhibited a higher risk of combined necrosis (56.9 %, 55.8 %; respectively), and elderly patients more frequently had extensive extrapancreatic involvement compared with young patients (65.9 % vs 21.4 %; p = 0.004); however, PN alone was more common in young patients. These characteristics of ANP were significantly bound up with clinical outcomes.

CONCLUSIONS

Different subtypes of ANP have different outcomes. More importantly, age needs to be considered as a factor of special concern in development of ANP.

Practical guide to the management of acute pancreatitis

Acute pancreatitis (AP) is characterised by inflammation of the exocrine pancreas and is associated with acinar cell injury and both a local and systemic inflammatory response. AP may range in severity from self-limiting, characterised by mild pancreatic oedema, to severe systemic inflammation with pancreatic necrosis, organ failure and death. Several international guidelines have been developed including those from the joint International Association of Pancreatology and American Pancreatic Association, American College of Gastroenterology and British Society of Gastroenterology. Here we discuss current diagnostic and management challenges and address the common dilemmas in AP.

Management of infected pancreatic necrosis in the intensive care unit: a narrative review

BACKGROUND

Severe acute pancreatitis is marked by organ failure and (peri)pancreatic necrosis with local complications such as infected necrosis. Infection of these necrotic collections together with organ failure remain the major causes of admission to an intensive care unit (ICU) in acute pancreatitis. Appropriate treatment of infected necrosis is essential to reduce morbidity and mortality. Overall knowledge of the treatment options within a multidisciplinary team-with special attention to the appropriate use of antimicrobial therapy and invasive treatment techniques for source control-is essential in the treatment of this complex disease.

OBJECTIVES

To address the current state of microbiological diagnosis, antimicrobial treatment, and source control for infected pancreatic necrosis in the ICU.

SOURCES

A literature search was performed using the Medline and Cochrane libraries for articles subsequent to 2003 using the keywords: infected necrosis, pancreatitis, intensive care medicine, treatment, diagnosis and antibiotic(s).

CONTENT

This narrative review provides an overview of key elements of diagnosis and treatment of infected pancreatic necrosis in the ICU.

IMPLICATIONS

In pancreatic necrosis it is essential to continuously (re)evaluate the indication for antimicrobial treatment and invasive source control. Invasive diagnostics (e.g. through fine-needle aspiration, FNA), preferably prior to the start of broad-spectrum antimicrobial therapy, is advocated. Antimicrobial stewardship principles apply: paying attention to altered pharmacokinetics in the critically ill, de-escalation of broad-spectrum therapy once cultures become available, and early withdrawal of antibiotics once source control has been established. This is important to prevent the development of antimicrobial resistance, especially in a group of patients who may require repeated courses of antibiotics during the prolonged course of their illness.

Multivariate analysis of the factors affecting the prognosis of walled-off pancreatic necrosis after endoscopic ultrasound-guided drainage

BACKGROUND AND AIMS

Endoscopic ultrasound (EUS)-guided drainage has become the treatment of choice for walled-off pancreatic necrosis (WOPN). However, no consensus exists on the most significant patient- and procedure-related factors that affect prognosis. The aim of the study is to investigate the correlation between patient- and procedure-related factors and post-procedure complications after EUS-guided drainage.

METHODS

A retrospective analysis of the clinical characteristics of patients with WOPN who underwent EUS-guided drainage at our endoscopy center between November 2011 and August 2017 was performed. Chi-square analysis and binary logistic regression statistical methods were used to analyze the correlation between influencing factors and prognosis.

RESULTS

A total of 85 patients (male/female, 50/35) with WOPN were included in the study. The average age was 44.95 years. The cyst diameter was 10.58 ± 4.78 cm. Multivariate analysis showed that WOPN with higher solid content (> 30%) increased the probability of endoscopic necrosectomy (OR 6.798; 95% CI 1.423, 32.470; p = 0.016). The use of a metal stent increased the probability of endoscopic necrosectomy (OR 3.503; 95% CI 1.251, 9.810; p = 0.017) and the length of hospitalization (OR 3.315; 95% CI 1.192, 9.215; p = 0.022). Female patients had a higher probability of requiring endoscopic necrosectomy (OR 2.683; 95% CI 1.027, 7.007; p = 0.044) and prolonged hospitalization (OR 2.675; 95% CI 1.065, 6.721; p = 0.036).

CONCLUSION

The solid content of WOPN, type of stent, and sex of patients were associated with increased probability of endoscopic necrosectomy.

An overview of walled-off pancreatic necrosis for clinicians

Walled of pancreatic necrosis (WOPN) is a new term coined for encapsulated fluid collection developing after acute necrotising pancreatitis (ANP). It is a heterogeneous collection containing varying amount of liquid as well as solid necrotic material. The literature on its natural history as well as appropriate management is gradually expanding thereby improving treatment outcomes of this enigmatic disease. Areas covered: This review discusses currently available literature on etiology, frequency, natural history, and imaging features WOPN. Also, updated treatment options including endoscopic, radiological and surgical drainage are discussed. Expert opinion: WOPN is alocal complication of ANP occurring in the delayed phase of ANP and may be asymptomatic (50%) or present with pain, fever, jaundice, or gastric outlet obstruction. Natural courses of asymptomatic WOPN have been infrequently studied, and it appears that the majority remain asymptomatic and resolve spontaneously. Magnetic resonance imaging and endoscopic ultrasound are the best imaging modalities to evaluate solid necrotic debris. Symptomatic WOPN usually needs immediate drainage, this can be done endoscopically, radiologically, or surgically. Current evidence suggests that endoscopic transluminal drainage is the preferred drainage technique as it is effective and associated with lower mortality, risk of organ failure, adverse effects, and length of hospital stay.

Endoscopic Drainage of Pancreatic Fluid Collections

Endoscopy has emerged as a mainstay in the management of pancreatic fluid collections (PFCs), representing an important advance in clinical medicine that has significantly improved the risk-benefit ratio of treating this complex patient population. While endoscopic pseudocyst drainage has generally supplanted surgical and percutaneous approaches, the optimal strategy for walled-off necrosis remains variable and multi-disciplinary despite an emerging trend from randomized trials favoring endoscopy. Although several issues pertaining to endoscopic drainage appear to have been settled - such as the use of endoscopic ultrasound - other pressing questions - including the optimal prosthesis and debridement strategy - remain unanswered, and rigorous investigation is needed. This review aims to provide an evidence-based but practical appraisal of the endoscopic drainage of PFCs through the perspective of the author, with an emphasis on relevant clinical and endoscopic considerations and important research questions.

The importance of acoustic radiation force impulse (ARFI) elastography in the diagnosis and clinical course of acute pancreatitis

BACKGROUND/AIMS

Acute pancreatitis (AP) is characterized by acute inflammation of the pancreas and it has a highly variable clinical course. The aim of our study was to evaluate the value of acoustic radiation force impulse (ARFI) elastography in the diagnosis and clinical course of AP.

MATERIALS AND METHODS

Consecutive patients with a diagnosis of AP (patients group) and healthy subject (control group) were prospectively enrolled to the study. Demographic features and clinical, laboratory, and radiological data were recorded. Virtual Touch Tissue Quantification (VTQ) was used to implement ARFI elastography. The tissue elasticity is proportional to the square of the wave velocity (SWV).

RESULTS

A total of 108 patients (age, 57±1.8 y) and 79 healthy subjects (age, 53.6±1.81 y) were included in the study. There were 100 (92.5%) edematous and 8 (7.4%) necrotizing AP. The mean SWV was significantly higher in the patient group than in the control group (2.43±0.08 vs. 1.27±0.025 m/s, p < 0.001). There was not significant difference between patient and control group regarding age and gender. SWV cutoff value of 1.63 m/s was associated with 100% sensitivity and 98% specificity for the diagnosis of AP. There was not significant difference between patients with and without complications and patients with edematous and necrotizing AP regarding mean SWV value. There was also not significant correlation between mean SWV value and age, mean length of hospital stay, and mean amylase level.

CONCLUSION

ARFI elastography may be a feasible method for the diagnosis of AP, but it has no value for the prediction of clinical course of AP.

The Evolution of EUS-Guided Transluminal Drainage for the Treatment of Pancreatic Fluid Collections: A Comparison of Clinical and Cost Outcomes with Double-Pigtail Plastic Stents, Conventional Metal Stents and Lumen-Apposing Metal Stents

Background

While most pancreatic fluid collections (PFCs) resolve spontaneously, endoscopic ultrasound-guided transluminal drainage (EUS-TD) may be necessary. EUS-TD has evolved from multiple double-pigtail plastic stents (DPPS) to fully covered self-expanding metal stents (FCSEMS) and lumen-apposing metal stents (LAMS). This study compares clinical attributes of DPPS, FCSEMS and LAMS.

Methods

This is a single-centre retrospective review of EUS-TD for PFCs. The primary outcome was clinical success. Secondary outcomes were technical success, procedure time, hospital length of stay (HLOS), number of endoscopies, need for necrosectomy, adverse events (AEs) and overall cost.

Results

Fifty-eight patients (37 male, average age 49 years) underwent a total of 60 EUS-TD procedures for PFCs (average size 11.2 cm with 29 pseudocysts and 29 walled-off necrosis). Ten patients (17%) underwent EUS-TD with DPPS and 48 patients (83%) with metal stents (32 FCSEMS, 16 LAMS). Overall technical and clinical success was 100% and 84%, respectively. Lumen-apposing metal stents had shorter procedure times (14.9 versus 63.6 DPPS, 39.1 min FCSEMS, P < 0.001), and no difference in AEs (3 of 16 versus 4 of 10 DPPS, 12 of 34 FCSEMS, ns). Double-pigtail plastic stents required more endoscopies (3.7 versus 2.3 LAMS, 2.3 FCSEMS, P = 0.013) and necrosectomies (4 of 10 [40%]) compared with 5 of 34 [15%] in the FCSEMS group and 3 of 16 [19%] in the LAMS group, respectively, P = 0.001) to achieve clinical resolution. The overall cost and HLOS was not significantly different between groups.

Conclusion

The use of LAMS for PFCs is not associated with any significant increase in cost despite technical (shorter procedure time) and clinical advantages (shorter indwell time, reduced need for necrosectomy and no increase in AEs).

Acute Pancreatitis in Chronic Dialysis Patients

The annual incidence of acute pancreatitis (AP) ranges from 4.9 to 73.4 cases per 100,000 worldwide. Patients with end-stage renal disease on dialysis have an increased risk for developing AP compared with patients without renal disease. In addition to the general population risk factors, there are factors related to renal insufficiency and dialysis process that might predispose to AP in this population. Clinical features and diagnosis are the same as those in patients without renal failure; however, amylase and lipase levels should be interpreted cautiously as they might be falsely elevated in renal failure. In this article, we will describe the risk factors that are exclusive to this population. In addition, we will also focus on the laboratory indices and clinical features that are unique to this population with patients with end-stage renal disease.

Consensus guidelines on the optimal management in interventional EUS procedures: results from the Asian EUS group RAND/UCLA expert panel

OBJECTIVES

Interventional endoscopic ultrasonography (EUS) procedures are gaining popularity and the most commonly performed procedures include EUS-guided drainage of pancreatic pseudocyst, EUS-guided biliary drainage, EUS-guided pancreatic duct drainage and EUS-guided celiac plexus ablation. The aim of this paper is to formulate a set of practice guidelines addressing various aspects of the above procedures.

METHODS

Formulation of the guidelines was based on the best scientific evidence available. The RAND/UCLA appropriateness methodology (RAM) was used. Panellists recruited comprised experts in surgery, interventional EUS, interventional radiology and oncology from 11 countries. Between June 2014 and October 2016, the panellists met in meetings to discuss and vote on the clinical scenarios for each of the interventional EUS procedures in question.

RESULTS

A total of 15 statements on EUS-guided drainage of pancreatic pseudocyst, 15 statements on EUS-guided biliary drainage, 12 statements on EUS-guided pancreatic duct drainage and 14 statements on EUS-guided celiac plexus ablation were formulated. The statements addressed the indications for the procedures, technical aspects, pre- and post-procedural management, management of complications, and competency and training in the procedures. All statements except one were found to be appropriate. Randomised studies to address clinical questions in a number of aspects of the procedures are urgently required.

CONCLUSIONS

The current guidelines on interventional EUS procedures are the first published by an endoscopic society. These guidelines provide an in-depth review of the current evidence and standardise the management of the procedures.

Predictive Value of Computed Tomography Scans and Clinical Findings for the Need of Endoscopic Necrosectomy in Walled-off Necrosis From Pancreatitis

OBJECTIVES

Choosing the best treatment option at the optimal point of time for patients with walled-off necrosis (WON) is crucial. We aimed to identify imaging parameters and clinical findings predicting the need of necrosectomy in patients with WON.

METHODS

All patients with endoscopically diagnosed WON and pseudocyst were retrospectively identified. Post hoc analysis of pre-interventional contrast-enhanced computed tomography was performed for factors predicting the need of necrosectomy.

RESULTS

Sixty-five patients were included in this study. Forty patients (61.5%) were diagnosed with pseudocyst and 25 patients (38.5%) with WON. Patients with WON mostly had acute pancreatitis with biliary cause compared with more chronic pancreatitis and toxic cause in pseudocyst group (P = 0.002 and P = 0.004, respectively). Logistic regression revealed diabetes as a risk factor for WON. Computed tomography scans revealed 4.62% (n = 3) patients as false positive and 24.6% (n = 16) as false negative findings for WON. Reduced perfusion and detection of solid findings were independent risk factors for WON.

CONCLUSIONS

Computed tomography scans are of low diagnostic yield when needed to predict treatment of patients with pancreatic cysts. Reduced pancreatic perfusion and solid findings seem to be a risk factor for WON, whereas patients with diabetes seem to be at higher risk of developing WON.

Describing Peripancreatic Collections According to the Revised Atlanta Classification of Acute Pancreatitis: An International Interobserver Agreement Study

OBJECTIVES

Severe acute pancreatitis is associated with peripancreatic morphologic changes as seen on imaging. Uniform communication regarding these morphologic findings is crucial for accurate diagnosis and treatment. For the original 1992 Atlanta classification, interobserver agreement is poor. We hypothesized that for the revised Atlanta classification, interobserver agreement will be better.

METHODS

An international, interobserver agreement study was performed among expert and nonexpert radiologists (n = 14), surgeons (n = 15), and gastroenterologists (n = 8). Representative computed tomographies of all stages of acute pancreatitis were selected from 55 patients and were assessed according to the revised Atlanta classification. The interobserver agreement was calculated among all reviewers and subgroups, that is, expert and nonexpert reviewers; interobserver agreement was defined as poor (≤0.20), fair (0.21-0.40), moderate (0.41-0.60), good (0.61-0.80), or very good (0.81-1.00).

RESULTS

Interobserver agreement among all reviewers was good (0.75 [standard deviation, 0.21]) for describing the type of acute pancreatitis and good (0.62 [standard deviation, 0.19]) for the type of peripancreatic collection. Expert radiologists showed the best and nonexpert clinicians the lowest interobserver agreement.

CONCLUSIONS

Interobserver agreement was good for the revised Atlanta classification, supporting the importance for widespread adaption of this revised classification for clinical and research communications.

The role of endoscopic intervention in the management of inflammatory pancreatic fluid collections

Pancreatic fluid collections (PFCs) are a frequent complication of pancreatitis, or less commonly, pancreatic trauma or surgery. The revised Atlanta Classification categorizes PFCs as acute or chronic, with further subclassification of acute collections into acute peripancreatic collections and acute necrotic collections and of chronic fluid collections into pseudocysts and walled-off pancreatic necrosis. Acute PFCs are generally only subjected to an intervention when they are infected and not responding to antibiotics and are not managed endoscopically. Chronic PFCs, both pseudocysts and walled-off pancreatic necrosis, require intervention only when symptomatic or enlarging over time. Endoscopic ultrasound-guided drainage has become the mainstay of management for chronic PFCs that require intervention. Developments in medical devices over the past few years have significantly simplified and shortened the duration of the procedure itself, but the optimum choice of stent in different clinical scenarios remains to be defined, as does the place of endoscopic necrosectomy. To optimize outcomes, these patients should undergo a careful preprocedure workup and discussion in a multidisciplinary environment and procedures should be carried out in high-volume pancreatic units.

Asian consensus statements on endoscopic management of walled-off necrosis Part 1: Epidemiology, diagnosis, and treatment

Walled-off necrosis (WON) is a relatively new term for encapsulated necrotic tissue after severe acute pancreatitis. Various terminologies such as pseudocyst, necroma, pancreatic abscess, and infected necrosis were previously used in the literature, resulting in confusion. The current and past terminologies must be reconciled to meaningfully interpret past data. Recently, endoscopic necrosectomy was introduced as a treatment option and is now preferred over surgical necrosectomy when the expertise is available. However, high-quality evidence is still lacking, and there is no standard management strategy for WON. The consensus meeting aimed to clarify the diagnostic criteria for WON and the role of endoscopic interventions in its management. In the Consensus Conference, 27 experts from eight Asian countries took an active role and examined key clinical aspects of WON diagnosis and endoscopic management. Statements were crafted based on literature review and expert opinion, employing the modified Delphi method. All statements were substantiated by the level of evidence and the strength of the recommendation. We created 27 consensus statements for WON diagnosis and management, including details of endoscopic procedures. When there was not enough solid evidence to support the statements, this was clearly acknowledged to facilitate future research. Proposed management strategies were formulated and are illustrated using flow charts. These recommendations, which are based on the best current scientific evidence and expert opinion, will be useful for guiding endoscopic management of WON. Part 1 of this statement focused on the epidemiology, diagnosis, and timing of intervention.

Significant inter-observer variation in the diagnosis of extrapancreatic necrosis and type of pancreatic collections in acute pancreatitis - An international multicenter evaluation of the revised Atlanta classification

BACKGROUND

For consistent reporting and better comparison of data in research the revised Atlanta classification (RAC) proposes new computed tomography (CT) criteria to describe the morphology of acute pancreatitis (AP). The aim of this study was to analyse the interobserver agreement among radiologists in evaluating CT morphology by using the new RAC criteria in patients with AP.

METHODS

Patients with a first episode of AP who obtained a CT were identified and consecutively enrolled at six European centres backwards from January 2013 to January 2012. A local radiologist at each center and a central expert radiologist scored the CTs separately using the RAC criteria. Center dependent and independent interobserver agreement was determined using Kappa statistics.

RESULTS

In total, 285 patients with 388 CTs were included. For most CT criteria, interobserver agreement was moderate to substantial. In four categories, the center independent kappa values were fair: extrapancreatic necrosis (EXPN) (0.326), type of pancreatitis (0.370), characteristics of collections (0.408), and appropriate term of collections (0.356). The fair kappa values relate to discrepancies in the identification of extrapancreatic necrotic material. The local radiologists diagnosed EXPN (33% versus 59%, P < 0.0001) and non-homogeneous collections (35% versus 66%, P < 0.0001) significantly less frequent than the central expert. Cases read by the central expert showed superior correlation with clinical outcome.

CONCLUSION

Diagnosis of EXPN and recognition of non-homogeneous collections show only fair agreement potentially resulting in inconsistent reporting of morphologic findings.

Magnetic resonance imaging of retroperitoneal interfascial plane involvement in acute pancreatitis

BACKGROUND

To study the magnetic resonance imaging (MRI) features of acute pancreatitis (AP) involving the retroperitoneal interfascial planes and to analyze the correlations of interfascial plane involvement with the magnetic resonance severity index (MRSI) and the Acute Physiology and Chronic Health Evaluation (APACHE II) scoring system.

METHODS

A total of 316 consecutive patients with AP between November 2011 and August 2013 were retrospectively analyzed. The extension and path of the inflammation spreading along the retroperitoneal interfascial plane on MRI were graded from grade 0 to grade 5. The relationships between interfascial plane involvement and MRSI and APACHE II were analyzed.

RESULTS

Of the 316 patients with AP, 293 patients (92.7%) had interfascial plane involvement, which appeared as interfascial plane edema, thickening and effusion. There were 60, 105, 78, 25, and 25 patients in grades 1, 2, 3, 4, and 5, respectively. Interfascial plane involvement strongly correlated with the MRSI score (r=0.703), but was only weakly correlated with the APACHE-II score (r=0.291).

CONCLUSIONS

MRI depicts the characteristics of interfascial plane involvement in AP. The value of interfascial plane involvement for determining the disease severity is likely to be limited.

Added value of diffusion-weighted magnetic resonance imaging for the detection of pancreatic fluid collection infection

OBJECTIVES

To investigate the added value of diffusion-weighted (DW) magnetic resonance (MR) imaging in the detection of infection in pancreatic fluid collections (PFC).

METHODS

Forty-patients with PFC requiring endoscopic-transmural drainage underwent conventional-MR and DW-MR imaging (b = 1000 s/mm²) before endoscopy. MR images were divided into two sets (set1, conventional-MR; set2, conventional-MR, DW-MR and ADC maps) and randomized. Two independent readers performed qualitative and quantitative (apparent diffusion coefficient, ADC) image analysis. Bacteriological analysis of PFC content was the gold standard. Non-parametric tests were used for comparisons. Sensitivity, specificity, negative predictive value (NPV), positive predictive value (PPV) and accuracy were calculated for the two sets for both readers. Receiver operating characteristic curves (ROC) were drawn to assess quantitative DW-MR imaging diagnostic performance.

RESULTS

For both readers, sensitivity, specificity, NPV, PPV and accuracy for infected PFCs were higher for set2 (P > .05). ADC were lower in infected versus non-infected PFCs (P ≤ .031). Minimum ADC cut-off: 1,090×10^-3 mm²/s for reader 1 and 1,012×10^-3 mm²/s for reader 2 (sensitivity and specificity 67 % and 96 % for both readers).

CONCLUSION

Qualitative information provided by DW-MR may help to assess PFCs infection. Infected PFCs show significantly lower ADCs compared to non-infected ones.

KEY POINTS

• DW improves MR diagnostic accuracy to detect infection of PFC • Infected PFCs show lower ADC compared to non-infected ones (P < .031) • DW-MR images are easy to interpret especially for non-experienced radiologist.

Acute Pancreatitis in Pediatric Patients: Demographics, Etiology, and Diagnostic Imaging

OBJECTIVE

The objective of this article is to provide updates on acute pancreatitis in children regarding the imaging findings, causes, and complications based on a review of the current studies in the pediatrics literature. We discuss the epidemiology of acute pancreatitis, the role of imaging and imaging findings in the diagnosis of acute pancreatitis, and the causes and complications of acute pancreatitis.

CONCLUSION

The incidence of acute pancreatitis is increasing in children. Imaging plays an important role in the diagnosis of acute pancreatitis because imaging findings can be used to establish the cause of acute pancreatitis, evaluate for complications of acute pancreatitis, and possibly predict the course of the disease.

CT and MRI assessment of symptomatic organized pancreatic fluid collections and pancreatic duct disruption: an interreader variability study using the revised Atlanta classification 2012

PURPOSE

Compare CT and MRI for fluid/debris component estimate and pancreatic duct (PD) communication with organized pancreatic fluid collections in acute pancreatitis. Evaluate fat density globules on CT as marker for debris.

METHODS

29 Patients with 46 collections with CECT and MRI performed ≥4 weeks of symptom onset assessed for necrotizing pancreatitis, estimated percentage of fluid volume and PD involvement by two radiologists on separate occasions. T2WI used as standard for estimated percentage of fluid volume. Presence of fat globules and fluid attenuation on CT was recorded. Spearman rank correlation and kappa statistics were used to assess the correlation between imaging techniques and interreader agreement, respectively.

RESULTS

Necrotizing pancreatitis seen on CT in 27 (93%, κ 0.119) vs. 20 (69%, κ 0.748) patients on MRI. CT identified 42 WON and 4 pseudocysts vs. 34 WON, and 12 pseudocysts on MRI. Higher interreader agreement for percentage fluid volume on MRI (κ = 0.55) vs. CT (κ = 0.196). Accuracy of CT in evaluation of percentage fluid volume was 65% using T2WI MRI used as standard. Fat globules identified on CT in 13(65%) out of 20 collections containing <75% fluid vs. 4(15%) out of 26 collections containing >75% fluid (p = 0.0001). PD involvement confidently excluded on CT in 68% collections vs. 93% on MRI.

CONCLUSION

MRI demonstrates higher reproducibility for fluid to debris component estimation. Fat globules on CT were frequently seen in organized pancreatic fluid collections with large amount of debris. PD disruption more confidently excluded on MRI. This information may be helpful for pre-procedure planning.

Pancreatic fluid collections: What is the ideal imaging technique?

Pancreatic fluid collections (PFCs) are seen in up to 50% of cases of acute pancreatitis. The Revised Atlanta classification categorized these collections on the basis of duration of disease and contents, whether liquid alone or a mixture of fluid and necrotic debris. Management of these different types of collections differs because of the variable quantity of debris; while patients with pseudocysts can be drained by straight-forward stent placement, walled-off necrosis requires multi-disciplinary approach. Differentiating these collections on the basis of clinical severity alone is not reliable, so imaging is primarily performed. Contrast-enhanced computed tomography is the commonly used modality for the diagnosis and assessment of proportion of solid contents in PFCs; however with certain limitations such as use of iodinated contrast material especially in renal failure patients and radiation exposure. Magnetic resonance imaging (MRI) performs better than computed tomography (CT) in characterization of pancreatic/peripancreatic fluid collections especially for quantification of solid debris and fat necrosis (seen as fat density globules), and is an alternative in those situations where CT is contraindicated. Also magnetic resonance cholangiopancreatography is highly sensitive for detecting pancreatic duct disruption and choledocholithiasis. Endoscopic ultrasound is an evolving technique with higher reproducibility for fluid-to-debris component estimation with the added advantage of being a single stage procedure for both diagnosis (solid debris delineation) and management (drainage of collection) in the same sitting. Recently role of diffusion weighted MRI and positron emission tomography/CT with ¹⁸F-FDG labeled autologous leukocytes is also emerging for detection of infection noninvasively. Comparative studies between these imaging modalities are still limited. However we look forward to a time when this gap in literature will be fulfilled.

Acute pancreatitis: international classification and nomenclature

The incidence of acute pancreatitis (AP) is increasing and it is associated with a major healthcare concern. New insights in the pathophysiology, better imaging techniques, and novel treatment options for complicated AP prompted the update of the 1992 Atlanta Classification. Updated nomenclature for pancreatic collections based on imaging criteria is proposed. Adoption of the newly Revised Classification of Acute Pancreatitis 2012 by radiologists should help standardise reports and facilitate accurate conveyance of relevant findings to referring physicians involved in the care of patients with AP. This review will clarify the nomenclature of pancreatic collections in the setting of AP.