Imaging of acute pancreatitis: update of the revised Atlanta classification

When Not to Operate on Acute Cases-A Surgeon's Perspective on Rapid Assessment of Emergency Abdominopelvic Computed Tomography

Clinical problem solving evolves in parallel with advances in technology and discoveries in the medical field. However, it always reverts to basic cognitive processes involved in critical thinking, such as hypothetical-deductive reasoning, pattern recognition, and compilation models. When dealing with cases of acute abdominal pain, clinicians should employ all available tools that allow them to rapidly refine their analysis for a definitive diagnosis. Therefore, we propose a standardized method for the quick assessment of abdominopelvic computed tomography as a supplement to the traditional clinical reasoning process. This narrative review explores the cognitive basis of errors in reading imaging. It explains the practical use of attenuation values, contrast phases, and windowing for non-radiologists and details a multistep protocol for finding radiological cues during CT reading and interpretation. This systematic approach describes the salient features and technical tools needed to ascertain the causality between clinical patterns and abdominopelvic changes visible on CT scans from a surgeon's perspective. It comprises 16 sections that should be read successively and that cover the entire abdominopelvic region. Each section details specific radiological signs and provides clear explanations for targeted searches, as well as anatomical and technical hints. Reliance on imaging in clinical problem solving does not make a decision dichotomous nor does it guarantee success in diagnostic endeavors. However, it contributes exact information for supporting the clinical assessments even in the most subtle and intricate conditions.

Novel classification system for walled-off necrosis: a step toward standardized nomenclature and risk-stratification framework

BACKGROUND AND AIMS

The optimal therapeutic approach for walled-off necrosis (WON) is not fully understood, given the lack of a validated classification system. We propose a novel and robust classification system based on radiologic and clinical factors to standardize the nomenclature, provide a framework to guide comparative effectiveness trials, and inform the optimal WON interventional approach.

METHODS

This was a retrospective analysis of patients who underwent endoscopic management of WON by lumen-apposing metal stent placement at a tertiary referral center. Patients were classified according to the proposed QNI classification system: quadrant ("Q"), represented an abdominal quadrant distribution; necrosis ("N"), denoted by the percentage of necrosis of WON; and infection ("I"), denoted as positive blood culture and/or systemic inflammatory response syndrome reaction with a positive WON culture. Two blinded reviewers classified all patients according to the QNI system. Patients were then divided into 2 groups: those with a lower QNI stratification (≤2 quadrants and ≤30% necrosis; group 1) and those with a higher stratification (≥3 quadrants, 2 quadrants with ≥30% necrosis, or 1 quadrant with >60% necrosis and infection; group 2). The primary outcome was mean time to WON resolution. Secondary procedural and clinical outcomes between the groups were compared.

RESULTS

Seventy-one patients (75% men) were included and stratified by the QNI classification; group 1 comprised 17 patients and group 2, 54 patients. Patients in group 2 had a higher number of necrosectomies, longer hospital stays, and more readmissions. The mean time to resolution was longer in group 2 than in group 1 (79.6 ± 7.76 days vs 48.4 ± 9.22 days, P = .02). The mortality rate was higher in group 2 (15% vs 0%, P = .18).

CONCLUSIONS

Despite the heterogeneous nature of WON in severe acute pancreatitis, a proposed QNI system may provide a standardized framework for WON classification to inform clinical trials, risk-stratify the disease course, and potentially inform an optimal management approach.

Extrapancreatic necrosis volume: A new tool in acute pancreatitis severity assessment?

BACKGROUND

Many scores have been suggested to assess the severity of acute pancreatitis upon onset. The extrapancreatic necrosis volume is a novel, promising score that appears to be superior to other scores investigated so far.

AIM

To evaluate the discriminatory power of extrapancreatic necrosis volume to identify severe cases of acute pancreatitis.

METHODS

A total of 123 patients diagnosed with acute pancreatitis at Institute of Gastroenterology and Hepatology, St Spiridon Hospital between January 1, 2017 and December 31, 2019 were analyzed retrospectively. Pancreatitis was classified according to the revised Atlanta classification (rAC) as mild, moderate, or severe. Severity was also evaluated by computed tomography and classified according to the computed tomography severity index (CTSI) and the modified CTSI (mCTSI). The results were compared with the extrapancreatic volume necrosis to establish the sensitivity and specificity of each method.

RESULTS

The CTSI and mCTSI imaging scores and the extrapancreatic necrosis volume were highly correlated with the severity of pancreatitis estimated by the rAC (r = 0.926, P < 0.001 and r = 0.950, P < 0.001; r = 0.784, P < 0.001, respectively). The correlation of C-reactive protein with severity was positive but not as strong, and was not significant (r = 0.133, P = 0.154). The best predictor for the assessment of severe pancreatitis was the extrapancreatic necrosis volume [area under the curve (AUC) = 0.993; 95% confidence interval (CI): 0.981-1.005], with a 99.5% sensitivity and 99.0% specificity at a cutoff value of 167 mL, followed by the mCTSI 2007 score (AUC = 0.972; 95%CI: 0.946-0.999), with a 98.0% sensitivity and 96.5% specificity, and the CTSI 1990 score (AUC = 0.969; 95%CI: 0.941-0.998), with a 97.0% sensitivity and 95.0% specificity.

CONCLUSION

Radiological severity scores correlate strongly and positively with disease activity. Extrapancreatic necrosis volume shows the best diagnostic accuracy for severe cases.

Meta-analysis of CT and MRI for differentiation of autoimmune pancreatitis from pancreatic adenocarcinoma

OBJECTIVES

To systematically determine the diagnostic performance of computed tomography (CT) and magnetic resonance imaging (MRI) for differentiating autoimmune pancreatitis (AIP) from pancreatic ductal adenocarcinoma (PDAC), with a comparison between the two imaging modalities.

METHODS

Literature search was conducted using PubMed and EMBASE databases to identify original articles published between 2009 and 2019 reporting the diagnostic performance of CT and MRI for differentiating AIP from PDAC. The meta-analytic sensitivity and specificity of CT and MRI were calculated, and compared using a bivariate random effects model. Subgroup analysis for differentiating focal AIP from PDAC was performed.

RESULTS

Of the 856 articles screened, 11 eligible articles are remained, i.e., five studies for CT, four for MRI, and two for both. The meta-analytic summary sensitivity and specificity of CT were 59% (95% confidence interval [CI], 41-75%) and 99% (95% CI, 88-100%), respectively, while those of MRI were 84% (95% CI, 68-93%) and 97% (95% CI, 87-99%). MRI had a significantly higher meta-analytic summary sensitivity than CT (84% vs. 59%, p = 0.02) but a similar specificity (97% vs. 99%, p = 0.18). In the subgroup analysis for focal AIP, the sensitivity for distinguishing between focal AIP and PDAC was lower than that for the overall analysis. MRI had a higher sensitivity than CT (76% vs. 50%, p = 0.28) but a similar specificity (97% vs. 98%, p = 0.07).

CONCLUSION

MRI might be clinically more useful to evaluate patients with AIP, particularly for differentiating AIP from PDAC.

KEY POINTS

• MRI had an overall good diagnostic performance to differentiate AIP from PDAC with a meta-analytic summary estimate of 83% for sensitivity and of 97% for specificity. • CT had a very high specificity (99%), but a suboptimal sensitivity (59%) for differentiating AIP from PDAC. • Compared with CT, MRI had a higher sensitivity, but a similar specificity.

Recent Advances in Diagnosis and Severity Assessment of Acute Pancreatitis

The incidence and prevalence of acute pancreatitis (AP) is increasing over time. The diagnosis of acute pancreatitis is established by revised Atlanta criteria (2012). Multiple criteria and scoring systems have been used for assessment of severity of AP. Majority of acute pancreatitis cases (80%) are mild, the challenge remains in early diagnosis, severity assessment and treatment of severe AP and its complications. Assessment of severity of AP is important part of management because line of treatment depends on aetiology and severity of acute pancreatitis. In this article a comprehensive review of recent advances in diagnosis and severity assessment of acute pancreatitis has been described.

Role of extrapancreatic necrosis volume in determining early prognosis in patients with acute pancreatitis

PURPOSE

This study aims to evaluate the capacity of the clinical and radiological findings and the extrapancreatic necrotic tissue volume in early (2-6 days) computerized tomography (CT) images of patients diagnosed with AP to predict reliably the temporary or permanent organ failure and other local or systemic complications due to pancreatitis.

MATERIALS AND METHODS

Adult patients who were diagnosed with AP based on Revised Atlanta classification and underwent abdomen CT scans between May 2015 and May 2018 were examined retrospectively. Extrapancreatic necrosis volume was compared to various clinical parameters that indicate the prognosis of AP such as C-reactive protein (CRP) at 48-72th h, organ failure, infection, requirement for percutaneous or surgical intervention, length of hospital stay, and mortality, and to various imaging-based scoring systems such as the computerized tomography severity index (CTSI) and the modified CTSI (mCTSI). The receiver operating characteristic (ROC) curve was used to estimate the optimal threshold for predicting clinical prognosis.

RESULTS

Extrapancreatic necrosis volume had moderate positive correlation with length of hospital stay (p = 0.0001) and CRP (at 48-72th h) (p = 0.0001) and strong positive correlation with CTSI (p = 0.0001), mCTSI (p = 0.0001), and white blood cell count (p = 0.0001).

CONCLUSION

Extrapancreatic necrosis volume was found to be particularly better in predicting organ failure and infection compared to the imaging-based scoring systems (Balthazar, CTSI, and mCTSI) and the laboratory-based scoring systems (CRP at 48-72th h).

TAFRO Syndrome Presenting with Retroperitoneal Panniculitis-like Computed Tomography Findings at Disease Onset

TAFRO syndrome is rare, and its pathophysiology remains unclear. We herein report the case of a 66-year-old man who presented at our emergency department with epigastric pain. Contrast-enhanced computed tomography (CT) showed high-density retroperitoneal panniculus with contrast enhancement. He was treated initially with a protease inhibitor and hydration, to little effect. Anasarca, thrombocytopenia, and renal dysfunction developed gradually, and TAFRO syndrome was diagnosed. He was treated successfully with prednisolone and cyclophosphamide, and subsequent CT findings showed improvement. Abnormal CT findings of the retroperitoneum may indicate the early stages of TAFRO syndrome before the presentation of typical ascites.

Prediction of Necrotizing Pancreatitis on Early CT Based on the Revised Atlanta Classification

Purpose

To investigate the clinical and CT features at admission to predict the progression to necrotizing pancreatitis (NP) in patients initially diagnosed with interstitial edematous pancreatitis (IEP).

Materials and Methods

Patients with IEP who underwent contrast-enhanced CT at admission and follow-up CT (< 14 days) were included (n = 178). Two radiologists performed a consensus review of follow-up CT scans and diagnosed the type of acute pancreatitis as IEP or NP. Laboratory findings at admission were recorded. Clinical, CT, and laboratory findings were compared between the IEP-IEP group and IEP-NP group using the chi-square test and the t-test. Multivariate analysis was also performed.

Results

There were 112 and 66 patients in the IEP-IEP and the IEP-NP groups, respectively. The proportion of patients with alcohol etiology was significantly larger in the IEP-NP group. Among the CT findings, the presence of peripancreatic fluid and heterogeneous parenchymal enhancement were more frequently observed in the IEP-NP group. Among the laboratory variables, serum C-reactive protein levels and white blood cell counts were significantly higher in the IEP-NP group. Multivariate analysis revealed that the presence of peripancreatic fluid and heterogeneous parenchymal enhancement were significant findings distinguishing the two groups.

Conclusion

CT findings, such as the presence of peripancreatic fluid and heterogeneous pancreatic parenchymal enhancement, may be helpful in predicting the progression to NP in patients initially diagnosed with IEP.

Early predictors of hyperlipidemic acute pancreatitis

The present study aimed to investigate early risk factors for hyperlipidemic acute pancreatitis (HLAP) in order to open up novel routes for its prevention and treatment. Demographics, laboratory data obtained within 48 h, enhanced computed tomography (CT) imaging data and the modified CT severity index (MCTSI) for 111 patients with HLAP who were assessed at Ordos Central Hospital (Ordos, China) between January 2015 and October 2017 were retrospectively analyzed. Of these, 17 patients progressed to infectious pancreatic necrosis (IPN) and 14 patients progressed to organ failure (OF), the occurrence of which were the study outcomes. The patients were divided into pairs groups: IPN and non-IPN, as well as OF and non-OF, and differences between the groups were determined regarding various clinicopathological parameters. Furthermore, univariate and multivariate regression analyses were performed to identify parameters associated with the risk of progression to IPN or OP. On univariate analysis, the following parameters were deemed as being significantly associated with the risk of IPN: Serum calcium ions, C-reactive protein (CRP), extent of necrosis, procalcitonin (PTC) and the MCTSI. Furthermore, calcium ions, red cell distribution width (RDW), extent of necrosis and the MCTSI were significantly associated with the risk of OF on univariate analysis. Multivariate logistic regression analysis for these parameters then indicated that CRP (P=0.014), RDW (P=0.025) and the extent of necrosis (P=0.022) were significant and independent predictors of progression; thus, these are early risk factors for patients with HLAP. Receiver operating characteristic curves were generated to evaluate the predictive value of these factors, and the area under the curve for the three parameters was 0.863 [95% confidence interval (CI), 0.646-0.886], 0.727 (95% CI, 0.651-0.803) and 0.833 (95% CI, 0.739-0.936), respectively. Therefore, CRP, RDW and the extent of necrosis are early predictive indexes for the risk of progression in HLAP.

MR imaging of hemorrhage associated with acute pancreatitis

PURPOSE

To study MRI findings of hemorrhage in acute pancreatitis (AP) and correlate the presence and extent of hemorrhage with the MR severity index (MRSI), Acute Physiology And Chronic Health Evaluation (APACHE) II scores, and clinical outcome.

MATERIALS AND METHODS

This retrospective study included 539 patients with AP. Hemorrhage was defined as areas of hyperintensity in or outside the pancreas on liver imaging with volume acceleration flexible (LAVA-Flex). The presence of hemorrhage was classified into three areas: within the pancreatic parenchyma, retroperitoneal space, and sub-or intraperitoneal space. Involvement of each area was awarded 1 point resulting in the hemorrhage severity index (HSI) score. The predicted severity of AP was graded by MRSI and APACHE II score. The association between HSI, MRSI, and APACHE II scores was analyzed. The length of hospital stay and organ dysfunction was used as clinical outcome parameters.

RESULTS

Among 539 AP patients, 62 (11.5%) had hemorrhage. The prevalence of hemorrhage was 1.1% (2/186), 13.9% (43/310), and 39.5% (17/43) in predicted mild, moderate, and severe AP, respectively, based on MRSI (χ² = 55.3, p = 0.00); and 7.7% (21/273) and 19.2% (18/94) in predicted mild and severe AP, respectively, based on APACHE II (χ² = 21.2, p = 0.00). HSI score significantly correlated with MRSI (r = 0.36, p < 0.001) and APACHE II scores (r = 0.21, p = 0.00). The prevalence of organ dysfunction was higher and length of hospital stay was longer in patients with hemorrhage than in those without hemorrhage (p < 0.01).

CONCLUSIONS

Hemorrhage in AP is common. The presence of hemorrhage, rather than its extent, correlates with poor clinical outcome.

The effect of non-steroidal anti-inflammatory drugs on severity of acute pancreatitis and pancreatic necrosis

Introduction Acute pancreatitis (AP) is a common emergency presentation and can be disabling. There is significant morbidity and mortality associated with AP, and it places a considerable burden on the healthcare system. Non-steroidal anti-inflammatory drugs (NSAIDs) have been shown to have a protective effect in some elective contexts. This retrospective study aimed to evaluate the effect of NSAIDs on the course of AP and the severity of the disease. Methods A retrospective analysis was carried out of 324 patients admitted as an emergency with a diagnosis of AP to two UK hospitals. Patients were divided into two groups: those already taking NSAIDs for other co-morbidities and those not taking NSAIDs. Variables compared included: admission to a high dependency or intensive care unit; pancreatic necrosis; pseudocyst development; need for surgery; serum inflammatory markers; modified early warning scores on days 1, 3 and 5; length of stay; and mortality. Results Patients not taking NSAIDs were more likely to have a C-reactive protein level of ≥150mg/l (p=0.007). Patients in the NSAID group experienced less pancreatic necrosis (p=0.019) and lower rates of pseudocyst formation (p=0.010). Other variables showed no difference between the two groups, specifically length of stay and mortality. Conclusions Routine NSAID use may exert a protective effect on the development of AP, its severity, and complications. Therapeutic use of NSAIDs in acute presentations with pancreatitis should be further evaluated.

Acute pancreatitis: A 7 year retrospective cohort study of the epidemiology, aetiology and outcome from a tertiary hospital in Jamaica

BACKGROUND

Acute pancreatitis (AP) is a significant cause of acute abdominal pain, morbidity and hospitalisation. There was previously a dearth of studies exploring the incidence, risk factors and outcome of AP in the Caribbean region.

MATERIALS AND METHODS

All patients with a diagnosis of AP admitted to the University Hospital of the West Indies (UHWI) between 2006 and 2012 were reviewed. The epidemiological profile, risk factors, clinical presentation and outcomes of patients with AP were retrospectively studied.

RESULTS

There were 70 females and 21 males with a median age of 44 years (range 2-86). The median age of males was significantly higher than that of females (p = 0.041). The incidence of AP was 74 per 100,000 admissions per year. Vomiting and abdominal tenderness were noted in the majority of patients. The most common aetiology was biliary disease (71.4%), idiopathic (12%), post-ERCP (6.6%) and alcohol (5.5%). Alcoholic pancreatitis was only seen in males whereas idiopathic and post-ERCP pancreatitis only occurred in females. The mean duration of hospitalisation was 9.51 ± 8.28 days. Disease severity was mild in 61.1%, moderately severe in 26.7%, and severe in 12.2% of patients. Factors associated with more severe disease included overweight/obesity, idiopathic aetiology and post-ERCP status. The case fatality rate was 2%.

CONCLUSION

The incidence of AP was 74/100,000 hospital admissions annually. There was an unusual female preponderance, with biliary pancreatitis being the most common type occurring at an equal frequency among males and females. Only 12.2% of the total cases seen were severe. The case fatality rate was 2%. Local health policy should target timely interventions for biliary pancreatitis and should also address the local factors affecting disease 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.

Revised Atlanta Classification for Acute Pancreatitis: A Pictorial Essay

The 2012 revised Atlanta classification is an update of the original 1992 Atlanta classification, a standardized clinical and radiologic nomenclature for acute pancreatitis and associated complications based on research advances made over the past 2 decades. Acute pancreatitis is now divided into two distinct subtypes, necrotizing pancreatitis and interstitial edematous pancreatitis (IEP), based on the presence or absence of necrosis, respectively. The revised classification system also updates confusing and sometimes inaccurate terminology that was previously used to describe pancreatic and peripancreatic collections. As such, use of the terms acute pseudocyst and pancreatic abscess is now discouraged. Instead, four distinct collection subtypes are identified on the basis of the presence of pancreatic necrosis and time elapsed since the onset of pancreatitis. Acute peripancreatic fluid collections (APFCs) and pseudocysts occur in IEP and contain fluid only. Acute necrotic collections (ANCs) and walled-off necrosis (WON) occur only in patients with necrotizing pancreatitis and contain variable amounts of fluid and necrotic debris. APFCs and ANCs occur within 4 weeks of disease onset. After this time, APFCs or ANCs may either resolve or persist, developing a mature wall to become a pseudocyst or a WON, respectively. Any collection subtype may become infected and manifest as internal gas, though this occurs most commonly in necrotic collections. In this review, the authors present a practical image-rich guide to the revised Atlanta classification system, with the goal of fostering implementation of the revised system into radiology practice, thereby facilitating accurate communication among clinicians and reinforcing the radiologist's role as a key member of a multidisciplinary team in treating patients with acute pancreatitis. (©)RSNA, 2016.

Analysis of risk factors related to gastrointestinal fistula in patients with severe acute pancreatitis: a retrospective study of 344 cases in a single Chinese center

BACKGROUND

Gastrointestinal fistula (GIF) in severe acute pancreatitis (SAP) is considered as a sparse episode and studied sporadically in the literature. There is paucity of data on the prediction of the effect on risk of GIF in patient with SAP. This study was aimed to investigate risk factors related to GIF in the development of SAP.

METHODS

The clinical data of 344 patients with SAP from 2011 to 2016 were reviewed retrospectively. All patients were divided into the GIF group and the non-GIF group, and their data analyzed with respect to 15 parameters were applied to explore potential risk factors for GIF in patients with SAP.

RESULTS

Of the 344 eligible patients, 52 (15.12%) progressed to GIF. Only occurrence of infected pancreatic and extra-pancreatic necrosis (IPN) (P = 0.004, OR = 3.012) and modified CT severity index (MCTSI) (P = 0.033, OR = 1.183) were proved to be independent risk factors for GIF in patients with SAP, and blood type B (P = 0.048, OR = 2.096, 95% CI: 0.748-3.562) indicated weaker association of risk factor for GIF. The early (48-72 h after admission) enteral nutrition (EEN) (P = 0.016, OR = 0.267) acted as a protective factor.

CONCLUSIONS

Occurrence of IPN and high MCTSI are independent risk factors for the development of GIF in patients with SAP, blood type B reveals a potential correlation with GIF in patients with SAP. EEN is helpful to prevent the progression of GIF secondary to SAP.

MDCT of acute pancreatitis: Intraindividual comparison of single-phase versus dual-phase MDCT for initial assessment of acute pancreatitis using different CT scoring systems

OBJECTIVES

The purpose of the retrospective study was to evaluate the additional value of dual-phase multidetector computed tomography (MDCT) protocols over a single-phase protocol on initial MDCT in patients with acute pancreatitis using three CT-based pancreatitis severity scores with regard to radiation dose.

METHODS

In this retrospective, IRB approved study MDCT was performed in 102 consecutive patients (73 males; 55years, IQR48-64) with acute pancreatitis. Inclusion criteria were CT findings of interstitial edematous pancreatitis (IP) or necrotizing pancreatitis (NP) and a contrast-enhanced dual-phase (arterial phase and portal-venous phase) abdominal CT performed at ≥72h after onset of symptoms. The severity of pancreatic and extrapancreatic changes was independently assessed by 2 observers using 3 validated CT-based scoring systems (CTSI, mCTSI, EPIC). All scores were applied to arterial phase and portal venous phase scans and compared to score results of portal venous phase scans, assessed ≥14days after initial evaluation. For effective dose estimation, volume CT dose index (CTDIvol) and dose length product (DLP) were recorded in all examinations.

RESULTS

In neither of the CT severity scores a significant difference was observed after application of a dual-phase protocol compared with a single-phase protocol (IP: CTSI: 2.7 vs. 2.5, p=0.25; mCTSI: 4.0 vs. 4.0, p=0.10; EPIC: 2.0 vs. 2.0, p=0.41; NP: CTSI: 8.0 vs. 7.0, p=0.64; mCTSI: 8.0 vs. 8.0, p=0.10; EPIC: 3.0 vs. 3.0, p=0.06). The application of a single-phase CT protocol was associated with a median effective dose reduction of 36% (mean dose reduction 31%) compared to a dual-phase CT scan.

CONCLUSIONS

An initial dual-phase abdominal CT after ≥72h after onset of symptoms of acute pancreatitis was not superior to a single-phase protocol for evaluation of the severity of pancreatic and extrapancreatic changes. However, the effective radiation dose may be reduced by 36% using a single-phase protocol.

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.

Artesunate ameliorates severe acute pancreatitis (SAP) in rats by inhibiting expression of pro-inflammatory cytokines and Toll-like receptor 4

Severe acute pancreatitis (SAP) is a severe clinical condition with significant morbidity and mortality. Multiple organs dysfunction (MOD) is the leading cause of SAP-related death. The over-release of pro-inflammatory cytokines such as IL-1β, IL-6, and TNF-α is the underlying mechanism of MOD; however, there is no effective agent against the inflammation. Herein, artesunate (AS) was found to increase the survival of SAP rats significantly when injected with 3.5% sodium taurocholate into the biliopancreatic duct in a retrograde direction, improving their pancreatic pathology and decreasing serum amylase and pancreatic lipase activities along with substantially reduced pancreatic IL-1β and IL-6 release. In vitro, AS-pretreatment strongly inhibited IL-1β and IL-6 release and their mRNA expressions in the pancreatic acinar cells treated with lipopolysaccharide (LPS) but exerted little effect on TNF-α release. Additionally, AS reduced the mRNA expressions of Toll-like receptor 4 (TLR4) and nuclear factor-κB (NF-κB) p65 as well as their protein expressions in the pancreatic acinar cells. In conclusion, our results demonstrated that AS could significantly protect SAP rats, and this protection was related to the reduction of digestive enzyme activities and pro-inflammatory cytokine expressions via inhibition of TLR4/NF-κB signaling pathway. Therefore, AS may be considered as a potential therapeutic agent against SAP.

Perfusion CT: can it predict the development of pancreatic necrosis in early stage of severe acute pancreatitis?

PURPOSE

Pancreatic necrosis is an important determinant of patient outcome in severe acute pancreatitis (SAP). This prospective study was conducted to evaluate if perfusion CT (PCT) can predict the development of necrosis at an early stage in SAP.

METHODS

PCT was performed within 72 h of abdominal pain in 57 consecutive admitted patients of acute pancreatitis, out of which four patients were excluded. Thirty-two patients were classified as SAP and 21 as mild acute pancreatitis (MAP) on the basis of APACHE II or SIRS criteria or presence of organ failure. All patients underwent a follow-up CECT at 3 weeks to look for pancreatic necrosis.

RESULTS

Out of 32 patients of SAP, 14 patients showed perfusion defects. The mean blood flow (BF) in these areas was 11.47 ± 5.56 mL/100 mL/min and median blood volume (BV) was 3.92 mL/100 mL (0.5-8.49 mL/100 mL). All these patients developed necrosis on follow-up scan. Two patients who did not show perfusion defects also developed necrosis. Remaining 37 patients (16 SAP and 21 MAP) did not show perfusion defect and did not develop necrosis on follow-up. All regions showing BF less than ≤23.45 mL/100 mL/min and BV ≤8.49 mL/100 mL developed pancreatic necrosis. The values of perfusion parameters may vary with the scanner, mathematical model and protocol used. The sensitivity and specificity of PCT for predicting pancreatic necrosis were 87.5% and 100%, respectively. The cut off values of BF and BV for predicting the development of pancreatic necrosis were 27.29 mL/100 mL/min and 8.96 mL/100 mL, respectively, based on ROC curve. PCT is a reliable tool for early prediction of pancreatic necrosis, which may open new avenues to prevent this ominous complication.

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.

Diagnosis of pancreatitis in dogs and cats

Pancreatitis is the most common disorder of the exocrine pancreas in both dogs and cats. Ante-mortem diagnosis of canine and feline pancreatitis can be challenging. The clinical picture of dogs and cats with pancreatitis varies greatly (from very mild to severe or even fatal) and is characterised by non-specific findings. Complete blood count, serum biochemistry profile and urinalysis should always be performed in dogs and cats suspected of having pancreatitis, although findings are not-specific for pancreatitis. Serum amylase and lipase activities and trypsin-like immunoreactivity (TLI) concentrations have no or only limited clinical value for the diagnosis of pancreatitis in either dogs or cats. Conversely, serum pancreatic lipase immunoreactivity (PLI) concentration is currently considered to be the clinicopathological test of choice for the diagnosis of canine and feline pancreatitis. Abdominal radiography is a useful diagnostic tool for the exclusion of other diseases that may cause similar clinical signs to those of pancreatitis. Abdominal ultrasonography can be very useful for the diagnosis of pancreatitis, but this depends largely on the clinician's experience. Histopathological examination of the pancreas is considered the gold standard for the diagnosis and classification of pancreatitis, but it is not without limitations. In clinical practice, a combination of careful evaluation of the animal's history, serum PLI concentration and abdominal ultrasonography, together with pancreatic cytology or histopathology when indicated or possible, is considered to be the most practical and reliable means for an accurate diagnosis or exclusion of pancreatitis compared with other diagnostic modalities.

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.

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.

Clinical outcomes and prognostic significance of early vs. late computed tomography in acute pancreatitis

BACKGROUND

Guidelines recommend that contrast-enhanced computed tomography (CT) should be carried out 72 hours after onset of an attack of acute pancreatitis (AP). However, the exact time beyond 72 hours at which CT will produce the best diagnostic yield for local complications, or whether doing a CT early in acute pancreatitis has any adverse effect on the course of disease, is not clear.

METHODS

The medical records of 214 consecutive patients with AP were analysed retrospectively and these patients were divided into two groups: the early CT group (CT done at 4-5 days after the onset of pain) and the late CT group (CT done in days 6-14 following onset of pain). The two groups were compared for differences in clinical outcomes and prognostic information obtained from CT, such as detection of pancreatic necrosis and local complications, and CT severity index.

RESULTS

Of 214 patients [143 (66.8%) males; mean age 39.87 ± 13.52 years], 21 patients were excluded as they did not undergo CT or CT was done more than 14 days after onset of an attack of AP. The early CT group included 114 patients, whilst the late CT group had 79. The mean CT severity index was higher in the late CT group (6.65 ± 2.27 vs. 5.52 ± 2.7; P = 0.005). The incidence of persistent organ failure in the early group was no different from that of the late group (38.6% vs. 49.4%; P = 0.143). Local complications were detected more often in the late CT group (84.8% vs. 68.4%; P = 0.011). There was no difference between the two groups in the need for percutaneous drainage, surgery, or mortality (all P > 0.05).

CONCLUSIONS

Although performing early CT does not adversely affect the outcome in AP, CT carried out more than 5 days after the onset of symptoms may detect more local complications.

Pancreatitis-imaging approach

Pancreatitis is defined as the inflammation of the pancreas and considered the most common pancreatic disease in children and adults. Imaging plays a significant role in the diagnosis, severity assessment, recognition of complications and guiding therapeutic interventions. In the setting of pancreatitis, wider availability and good image quality make multi-detector contrast-enhanced computed tomography (MD-CECT) the most used imaging technique. However, magnetic resonance imaging (MRI) offers diagnostic capabilities similar to those of CT, with additional intrinsic advantages including lack of ionizing radiation and exquisite soft tissue characterization. This article reviews the proposed definitions of revised Atlanta classification for acute pancreatitis, illustrates a wide range of morphologic pancreatic parenchymal and associated peripancreatic changes for different types of acute pancreatitis. It also describes the spectrum of early and late chronic pancreatitis imaging findings and illustrates some of the less common types of chronic pancreatitis, with special emphasis on the role of CT and MRI.

Endoscopic ultrasound in the diagnosis and treatment of pancreatic disease

Endoscopic ultrasound (EUS) is an important part of modern gastrointestinal endoscopy and now has an integral role in the diagnostic evaluation of pancreatic diseases. Furthermore, as EUS technology has advanced, it has increasingly become a therapeutic procedure, and the prospect of multiple applications of interventional EUS for the pancreas is truly on the near horizon. However, this review focuses on the established diagnostic and therapeutic roles of EUS that are used in current clinical practice. In particular, the diagnostic evaluation of acute pancreatitis, chronic pancreatitis, cystic pancreatic lesions and solid masses of the pancreas are discussed. The newer enhanced imaging modalities of elastography and contrast enhancement are evaluated in this context. The main therapeutic aspects of pancreatic EUS are then considered, namely celiac plexus block and celiac plexus neurolysis for pain control in chronic pancreatitis and pancreas cancer, and EUS-guided drainage of pancreatic fluid collections.

Treatment options for acute pancreatitis

This Review covers the latest developments in the treatment of acute pancreatitis. The Atlanta Classification of acute pancreatitis has been revised, proposing several new terms and abandoning some of the old and confusing terminology. The 2012 Revised Atlanta Classification and the determinant-based classification aim to universally define the different local and systemic complications and predict outcome. The most important differences between these classifications are discussed. Several promising treatment options for the early management of acute pancreatitis have been tested, including the use of enteral nutrition and antibiotics as well as novel therapies such as haemofiltration and protease inhibitors. The results are summarized and the quality of evidence is discussed. Finally, new developments in the management of patients with infected pancreatic necrosis are addressed, including the use of the 'step-up approach' and results of minimally invasive necrosectomy.

Classifications of acute pancreatitis: to Atlanta and beyond

Until Atlanta Classification (AC) made in 1992, there was not any classification of acute pancreatitis (AP). Last twenty years AC let us compare results and papers. But the increasing understanding of the pathophysiology of AP, improvements in diagnostic methods and the development of minimally invasive tools for radiological, endoscopic and surgical management of local complications, several authors have called for the AC to be reviewed. Last months, two new classifications of AP have been published. We made a historical review of AC, the two new classifications and a comparison between them.

Acute necrotizing pancreatitis: laboratory, clinical, and imaging findings as predictors of patient outcome

OBJECTIVE

In patients with acute necrotizing pancreatitis, we analyzed whether laboratory and clinical findings determined in the early phase of disease and morphologic features on contrast-enhanced CT (CECT) at the beginning of the late phase of disease are helpful in predicting patient outcome and whether CECT findings provide additional information in establishing prognosis compared with the laboratory and clinical findings.

MATERIALS AND METHODS

A retrospective analysis of 99 patients with acute necrotizing pancreatitis was performed. Four laboratory variables (albumin, calcium, C-reactive protein, WBC count) and three clinical variables (Acute Physiology, Age, Chronic Health Evaluation [APACHE] II score; Simplified Acute Physiology Score [SAPS] II; persistent organ failure) were assessed. Five morphologic features on CECT including Balthazar grade and CT severity index were reviewed. The endpoints of patient outcome were peripancreatic or pancreatic infection, need for intervention, duration of organ failure, ICU and hospital stays, and death. Based on receiver operating characteristic curve analysis for infection, high-and low-risk groups for each prognostic variable were calculated and univariable and multivariable Cox regression analyses were carried out.

RESULTS

In our study population of 99 patients (63 men, 36 women; median age, 52 years; age range, 18-84 years), 25 patients (25%) developed infection, 42 patients (42%) experienced organ failure, and 12 patients (12%) died. Regarding the laboratory and clinical variables, albumin level, APACHE II score, and particularly persistent organ failure were the strongest independent predictors of patient outcome. Regarding the imaging variables, Balthazar grade and a morphologic feature that takes the distribution of intrapancreatic necrosis into account were the strongest independent predictors. In the multivariable analysis of all studied variables, imaging variables were independent and strong predictors of patient outcome and provided additional information in establishing prognosis compared with clinical and laboratory findings.

CONCLUSION

In patients with suspected or proven acute necrotizing pancreatitis, performing CECT at the beginning of the late phase of disease is recommended to identify patients at increased risk for adverse outcomes.

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.

Staged multidisciplinary step-up management for necrotizing pancreatitis

Background

Some 15 per cent of all patients with acute pancreatitis develop necrotizing pancreatitis, with potentially significant consequences for both patients and healthcare services.

Methods

This review summarizes the latest insights into the surgical and medical management of necrotizing pancreatitis. General management strategies for the treatment of complications are discussed in relation to the stage of the disease.

Results

Frequent clinical evaluation of the patient's condition remains paramount in the first 24–72 h of the disease. Liberal goal-directed fluid resuscitation and early enteral nutrition should be provided. Urgent endoscopic retrograde cholangiopancreatography is indicated when cholangitis is suspected, but it is unclear whether this is appropriate in patients with predicted severe biliary pancreatitis without cholangitis. Antibiotic prophylaxis does not prevent infection of necrosis and antibiotics are not indicated as part of initial management. Bacteriologically confirmed infections should receive targeted antibiotics. With the more conservative approach to necrotizing pancreatitis currently advocated, fine-needle aspiration culture of pancreatic or extrapancreatic necrosis will less often lead to a change in management and is therefore indicated less frequently. Optimal treatment of infected necrotizing pancreatitis consists of a staged multidisciplinary ‘step-up’ approach. The initial step is drainage, either percutaneous or transluminal, followed by surgical or endoscopic transluminal debridement only if needed. Debridement is delayed until the acute necrotic collection has become ‘walled-off’.

Conclusion

Outcome following necrotizing pancreatitis has improved substantially in recent years as a result of a shift from early surgical debridement to a staged, minimally invasive, multidisciplinary, step-up approach.

[International multidisciplinary classification of acute pancreatitis severity: the 2013 Spanish edition]

OBJECTIVE

To develop a new classification of acute pancreatitis severity on the basis of a sound conceptual framework, comprehensive review of the published evidence, and worldwide consultation.

BACKGROUNDS

The Atlanta definitions of acute pancreatitis severity are ingrained in the lexicon of specialist in pancreatic diseases, but are suboptimal because these definitions are based on the empiric description of events not associated with severity.

METHODS

A personal invitation to contribute to the development of a new classification of acute pancreatitis severity was sent to all surgeons, gastroenterologists, internists, intensivists and radiologists currently active in the field of clinical acute pancreatitis. The invitation was not limited to members of certain associations or residents of certain countries. A global web-based survey was conducted, and a dedicated international symposium was organized to bring contributors from different disciplines together and discuss the concept and definitions.

RESULTS

The new classification of severity is based on the actual local and systemic determinants of severity, rather than on the description of events that are non-causally associated with severity. The local determinant relates to whether there is (peri) pancreatic necrosis or not, and if present, whether it is sterile or infected. The systemic determinant relates to whether there is organ failure or not, and if present, whether it is transient or persistent. The presence of one determinant can modify the effect of another, whereby the presence of both infected (peri) pancreatic necrosis and persistent organ failure has a greater impact upon severity than either determinant alone. The derivation of a classification based on the above principles results in four categories of severity: mild, moderate, severe, and critical.

CONCLUSIONS

This classification is the result of a consultative process among specialists in pancreatic diseases from 49 countries spanning North America, South America, Europe, Asia, Oceania and Africa. It provides a set of concise up to date definitions of all the main entities pertinent to classifying the severity of acute pancreatitis in clinical practice and research. This ensures that the determinant-based classification can be used in a uniform manner throughout the world.

Clinical management of patients with acute pancreatitis

Acute pancreatitis is the leading cause of hospitalization for gastrointestinal disorders in the United States. As rates of hospitalization for acute pancreatitis continue to increase, so does demand for effective management. We review approaches to best manage patients with acute pancreatitis, covering diagnosis, risk and prognostic factors, treatment, and complications, considering recommendations from current practice guidelines.

Determinant-based classification of acute pancreatitis severity: an international multidisciplinary consultation

OBJECTIVE

To develop a new international classification of acute pancreatitis severity on the basis of a sound conceptual framework, comprehensive review of published evidence, and worldwide consultation.

BACKGROUND

The Atlanta definitions of acute pancreatitis severity are ingrained in the lexicon of pancreatologists but suboptimal because these definitions are based on empiric description of occurrences that are merely associated with severity.

METHODS

A personal invitation to contribute to the development of a new international classification of acute pancreatitis severity was sent to all surgeons, gastroenterologists, internists, intensivists, and radiologists who are currently active in clinical research on acute pancreatitis. The invitation was not limited to members of certain associations or residents of certain countries. A global Web-based survey was conducted and a dedicated international symposium was organized to bring contributors from different disciplines together and discuss the concept and definitions.

RESULT

The new international classification is based on the actual local and systemic determinants of severity, rather than description of events that are correlated with severity. The local determinant relates to whether there is (peri)pancreatic necrosis or not, and if present, whether it is sterile or infected. The systemic determinant relates to whether there is organ failure or not, and if present, whether it is transient or persistent. The presence of one determinant can modify the effect of another such that the presence of both infected (peri)pancreatic necrosis and persistent organ failure have a greater effect on severity than either determinant alone. The derivation of a classification based on the above principles results in 4 categories of severity-mild, moderate, severe, and critical.

CONCLUSIONS

This classification is the result of a consultative process amongst pancreatologists from 49 countries spanning North America, South America, Europe, Asia, Oceania, and Africa. It provides a set of concise up-to-date definitions of all the main entities pertinent to classifying the severity of acute pancreatitis in clinical practice and research. This ensures that the determinant-based classification can be used in a uniform manner throughout the world.