The role of nonenhanced magnetic resonance imaging in the early assessment of acute pancreatitis

Pancreatic Iodine Density and Fat Fraction on Dual-Energy Computed Tomography in Acute Pancreatitis

The aim of our study was to investigate iodine density (ID) and fat fraction (FF) on dual-energy computed tomography (DECT) in patients with acute pancreatitis (AP). This retrospective study included 72 patients with clinically confirmed AP and 62 control subjects with DECT of the abdomen. Two radiologists assessed necrosis and measured attenuation values, ID, and FF in three pancreatic segments. We used receiver operating characteristic (ROC) analysis to determine the optimal threshold for ID for the differentiation between AP groups. The ID was significantly higher in interstitial edematous AP compared to necrotizing AP and the control group (both p < 0.05). The ROC curve analysis revealed the thresholds of ID for detecting pancreatic necrosis ≤ 2.2, ≤2.3, and ≤2.4 mg/mL (AUC between 0.880 and 0.893, p > 0.05) for the head, body, and tail, respectively. The FF was significantly higher for pancreatitis groups when compared with the control group in the head and body segments (both p < 0.001). In the tail, the difference was significant in necrotizing AP (p = 0.028). The ID values were independent of attenuation values correlated with the FF values in pancreatic tissue. Iodine density values allow for differentiation between morphologic types of AP.

American College of Gastroenterology Guidelines: Management of Acute Pancreatitis

Acute pancreatitis (AP), defined as acute inflammation of the pancreas, is one of the most common diseases of the gastrointestinal tract leading to hospital admission in the United States. It is important for clinicians to appreciate that AP is heterogenous, progressing differently among patients and is often unpredictable. While most patients experience symptoms lasting a few days, almost one-fifth of patients will go on to experience complications, including pancreatic necrosis and/or organ failure, at times requiring prolonged hospitalization, intensive care, and radiologic, surgical, and/or endoscopic intervention. Early management is essential to identify and treat patients with AP to prevent complications. Patients with biliary pancreatitis typically will require surgery to prevent recurrent disease and may need early endoscopic retrograde cholangiopancreatography if the disease is complicated by cholangitis. Nutrition plays an important role in treating patients with AP. The safety of early refeeding and importance in preventing complications from AP are addressed. This guideline will provide an evidence-based practical approach to the management of patients with AP.

Acute pancreatitis: A review of diagnosis, severity prediction and prognosis assessment from imaging technology, scoring system and artificial intelligence

Acute pancreatitis (AP) is a potentially life-threatening inflammatory disease of the pancreas, with clinical management determined by the severity of the disease. Diagnosis, severity prediction, and prognosis assessment of AP typically involve the use of imaging technologies, such as computed tomography, magnetic resonance imaging, and ultrasound, and scoring systems, including Ranson, Acute Physiology and Chronic Health Evaluation II, and Bedside Index for Severity in AP scores. Computed tomography is considered the gold standard imaging modality for AP due to its high sensitivity and specificity, while magnetic resonance imaging and ultrasound can provide additional information on biliary obstruction and vascular complications. Scoring systems utilize clinical and laboratory parameters to classify AP patients into mild, moderate, or severe categories, guiding treatment decisions, such as intensive care unit admission, early enteral feeding, and antibiotic use. Despite the central role of imaging technologies and scoring systems in AP management, these methods have limitations in terms of accuracy, reproducibility, practicality and economics. Recent advancements of artificial intelligence (AI) provide new opportunities to enhance their performance by analyzing vast amounts of clinical and imaging data. AI algorithms can analyze large amounts of clinical and imaging data, identify scoring system patterns, and predict the clinical course of disease. AI-based models have shown promising results in predicting the severity and mortality of AP, but further validation and standardization are required before widespread clinical application. In addition, understanding the correlation between these three technologies will aid in developing new methods that can accurately, sensitively, and specifically be used in the diagnosis, severity prediction, and prognosis assessment of AP through complementary advantages.

Revised Clinical Practice Guidelines of the Korean Pancreatobiliary Association for Acute Pancreatitis

Acute pancreatitis can range from a mild, self-limiting disease requiring no more than supportive care, to severe disease with life-threatening complications. With the goal of providing a recommendation framework for clinicians to manage acute pancreatitis, and to contribute to improvements in national health care, the Korean Pancreatobiliary Association (KPBA) established the Korean guidelines for acute pancreatitis management in 2013. However, many challenging issues exist which often lead to differences in clinical practices. In addition, with newly obtained evidence regarding acute pancreatitis, there have been great changes in recent knowledge and information regarding this disorder. Therefore, the KPBA committee underwent an extensive revision of the guidelines. The revised guidelines were developed using the Delphi method, and the main topics of the guidelines include the following: diagnosis, severity assessment, initial treatment, nutritional support, convalescent treatment, and the treatment of local complications and necrotizing pancreatitis. Specific recommendations are presented, along with the evidence levels and recommendation grades.

Magnetic Resonance Imaging in Gastrointestinal and Genitourinary Emergencies

While computed tomography (CT) offers faster cross-sectional imaging in the emergency department, owing to its concerns for higher radiation exposure, magnetic resonance imaging (MRI) applications in acute settings are increasingly validated. A significant proportion of patients present to the emergency department with abdominopelvic symptoms, most commonly acute abdominal pain. Early detection with imaging and timely intervention can significantly decrease morbidity and mortality in conditions such as acute pancreatitis or ovarian torsion. MRI encompasses better soft-tissue resolution, nonusage of ionizing radiation and iodinated contrast media, nonoperator dependency, and higher reproducibility. This review discusses the MRI protocols and applications in abdominopelvic emergencies.

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.

Current State of Imaging of Pediatric Pancreatitis: AJR Expert Panel Narrative Review

Pancreatitis is as common in children as it is in adults, though causes and accepted imaging strategies differ in children. In this narrative review we discuss the epidemiology of childhood pancreatitis and key imaging features for pediatric acute, acute recurrent, and chronic pancreatitis. We rely heavily on our collective experience in discussing advantages and disadvantages of different imaging modalities; practical tips for optimization of ultrasound, CT, and MRI with MRCP in children; and image interpretation pearls. Challenges and considerations unique to imaging pediatric pancreatitis are discussed, including timing of imaging, role of secretin-enhanced MRCP, utility of urgent MRI, severity prediction, autoimmune pancreatitis, and best methods for serial imaging. We suggest a methodical approach to pancreatic MRI interpretation in children and have included a sample structured report, and we provide consensus statements according to our experience imaging children with pancreatitis.

Magnetic resonance severity index assessed by T1-weighted imaging for acute pancreatitis: correlation with clinical outcomes and grading of the revised Atlanta classification-a narrative review

Acute pancreatitis (AP) is a common disease that may involve pancreas and peripancreatic tissues with a prevalence of up to 50 per 100,000 individuals for year. The Atlanta classification was assessed for the first time in 1992 and modified in 2012 in order to describe morphological features of AP and its complications. AP can be morphologically distinguished in two main types: interstitial edematous pancreatitis (IEP) and necrotizing pancreatitis (NEP). This classification is very important because the presence of necrosis is directly linked to local or systemic complications, hospital stays and death. Magnetic resonance (MR) is very useful to characterize morphological features in AP and its abdominal complications. Particularly we would like to underline the diagnostic, staging and prognostic role of T1-weighted images with fat suppression that could be significant to assess many features of the AP inflammatory process and its complications (detection of the pancreatic contour, pancreatic necrosis, presence of haemorrhage). Signs of inflammatory and edema are instead observed by T1-weighted images. MR cholangiopancreatography (MRCP) is necessary to study the main pancreatic duct and the extrahepatic biliary tract and contrast-enhancement magnetic resonance imaging (MRI) allows to assess the extent of necrosis and vascular injuries.

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.

MRI in acute pancreatitis

Computed tomography (CT) is the most commonly performed imaging test for acute pancreatitis. Nevertheless, magnetic resonance (MRI) imaging is useful in many specific situations. These include evaluating patients with acute pancreatitis who cannot receive iodinated CT contrast, elucidating the underlying cause of acute pancreatitis, assessing ductal disconnection and for guiding intervention of necrotic collections. Non-contrast MRI is superior to non-contrast CT and MRI for the diagnosis of acute pancreatitis. We discuss these specific uses of MRI in acute pancreatitis. We highlight the future advances in MRI including faster, free-breathing scans that allow MRI to be completed within 10 min.

Dynamic Contrast-Enhanced MRI for Measuring Pancreatic Perfusion in Acute Pancreatitis: A Preliminary Study

RATIONALE AND OBJECTIVES

To assess the characteristics of pancreatic perfusion in normal pancreas and acute pancreatitis (AP) by using dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI).

METHOD AND MATERIALS

Eighty-One AP patients and 26 normal subjects underwent DCE-MRI. The Omitk-Tool was used to analyze perfusion parameters such as K^trans, V_p^, and AUC. The parameters of pancreas between AP and control groups were compared. In AP patients, the parameters were compared between edematous and necrotizing pancreatitis and among different grades of AP as determined by MR severity index (MRSI) and the 2012 Revised Atlanta Classification of AP.

RESULTS

The K^trans, V_p^, and AUC values of AP were lower than those of the control group (p = 0.007, 0.000, and 0.025). According to MRSI, the K^trans and AUC values were significantly different between mild and moderate (p = 0.000, 0.000) and between mild and severe (p = 0.008, 0.016) AP but not between moderate and severe AP (p = 0.218, 0.217). Based on the 2012 Revised Atlanta Classification, the K^trans values were significantly different between mild and moderately severe (p = 0.000) and between mild and severe (p = 0.005) AP, but not between moderately severe and severe AP (p = 0.619). The K^trans values were significantly different between edematous and necrotizing pancreatitis (p = 0.03).

CONCLUSION

The application of DCE-MRI to evaluate pancreatic perfusion contributes to the diagnosis of AP and its severity grade. Pancreatic perfusion is lower in AP patients than in patients with a normal pancreas, and pancreatic perfusion tends to decrease as the severity of AP increases.

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.

Predictive factors for the mortality of acute pancreatitis on admission

Background and aims

The revised Atlanta classification is widely used for the evaluation of acute pancreatitis (AP) severity. However, this classification cannot be used within 48 hours of AP onset. The aim of this study was to investigate the predictive factors of mortality in patients with AP on admission.

Methods

We evaluated the association between AP mortality and clinical parameters at the time of admission in patients with AP from April 2013 to December 2017 at one university hospital and one tertiary care referral center.

Results

A total of 203 consecutive patients were enrolled. Nine patients (4.4%) died despite multidisciplinary treatment. In a multivariable analysis, hematocrit ≥ 40% (odds ratio [OR], 1.07; 95% confidence interval [CI], 1.01–1.13; P = 0.021), blood urea nitrogen (BUN) ≥ 40 mg/dL (OR, 1.26; 95% CI, 1.11–1.42; P < 0.001), base excess < -3.0 mmol/L (OR, 1.15; 95% CI, 1.04–1.26; P = 0.004), and inflammation extending to the rectovesical excavation (OR, 1.19; 95% CI, 1.10–1.30; P < 0.001) on admission were significantly associated with mortality.

Conclusion

Among the imaging findings, inflammation extending to the rectovesical excavation was the only independent predictive factor for mortality in AP. This simple finding, obtained on computed tomography without contrast agent on admission, might be a promising prognostic factor for AP.

Utility of MR Imaging in Abdominopelvic Emergencies

Acute abdominopelvic pain, a common symptom in emergency department patients, is challenging given the spectrum of differential diagnoses encompassing multiple organ systems, ranging from benign self-limiting to life-threatening and emergent. Diagnostic imaging is critical given its high accuracy and management guidance. A contrast-enhanced computed tomography (CT) scan is preferred given its widespread availability and speed of acquisition. MR imaging may be appropriate, usually performed for specific indications with tailored protocols. It is accurate for diagnosis and may be an alternative to CT. This article discusses the advantages and disadvantages, protocols, and appearances of MR imaging of common diagnoses.

Uncomplicated Acute Pancreatitis: Evidenced-Based Management Decisions

Acute pancreatitis is among the most common gastrointestinal disorders requiring hospitalization worldwide. Establishing the cause of acute pancreatitis ensures appropriate management and proper health care resource utilization. Causes of acute pancreatitis include biliary, alcohol use, hypertriglyceridemia, hypercalcemia, drug-induced, autoimmune, hereditary/genetic, and anatomic abnormalities. Fluid therapy remains the cornerstone of managing acute pancreatitis. This article provides a brief summary of current evidence-based practices in the diagnosis and management of uncomplicated acute pancreatitis.

Management of acute pancreatitis in the first 72 hours

PURPOSE OF REVIEW

Acute pancreatitis is a common condition that affects patients with varying degrees of severity and may lead to significant morbidity and mortality. The present article will review the current paradigm in acute pancreatitis management within the first 72 h of diagnosis.

RECENT FINDINGS

Patients presenting with acute pancreatitis should be evaluated clinically for signs and symptoms of organ failure in order to appropriately triage. Initial management should focus on fluid resuscitation, with some data to support Ringer's lactate over physiological saline. Routine use of prophylactic antibiotics in acute pancreatitis is not recommended, nor is urgent endoscopic retrograde cholangiopancreatography in the absence of concomitant acute cholangitis. Early oral feeding should be encouraged, not avoided, and use of parenteral nutrition is discouraged. Cholecystectomy during the same admission of biliary pancreatitis should be performed in order to prevent future acute pancreatitis episodes. Patients with acute pancreatitis secondary to alcohol should receive alcohol counseling. Finally, there is ongoing interest in the development of prognostic laboratory tests in acute pancreatitis and pharmacological therapies to reduce the inflammation that occurs in acute pancreatitis.

SUMMARY

Acute pancreatitis is a common and heterogeneous condition with the potential for significant morbidity. Best practices in acute pancreatitis management focus on triage, hydration and enteral feeding.

Pancreatitis

Acute pancreatitis is an inflammation of the glandular parenchyma of the retroperitoneal organ that leads to injury with or without subsequent destruction of the pancreatic acini. This inflammatory process can either result in a self-limited disease or involve life-threatening multiorgan complications. Chronic pancreatitis consists of endocrine and exocrine gland dysfunction that develops secondary to progressive inflammation and chronic fibrosis of the pancreatic acini with permanent structural damage. Recurrent attacks of acute pancreatitis can result in chronic pancreatitis; acute and chronic pancreatitis are different diseases with separate morphologic patterns. Acute pancreatitis has an increasing incidence but a decreasing mortality.

Recent advances in understanding and managing acute pancreatitis

This review highlights advances made in recent years in the diagnosis and management of acute pancreatitis (AP). We focus on epidemiological, clinical, and management aspects of AP. Additionally, we discuss the role of using risk stratification tools to guide clinical decision making. The majority of patients suffer from mild AP, and only a subset develop moderately severe AP, defined as a pancreatic local complication, or severe AP, defined as persistent organ failure. In mild AP, management typically involves diagnostic evaluation and supportive care resulting usually in a short hospital length of stay (LOS). In severe AP, a multidisciplinary approach is warranted to minimize morbidity and mortality over the course of a protracted hospital LOS. Based on evidence from guideline recommendations, we discuss five treatment interventions, including intravenous fluid resuscitation, feeding, prophylactic antibiotics, probiotics, and timing of endoscopic retrograde cholangiopancreatography (ERCP) in acute biliary pancreatitis. This review also highlights the importance of preventive interventions to reduce hospital readmission or prevent pancreatitis, including alcohol and smoking cessation, same-admission cholecystectomy for acute biliary pancreatitis, and chemoprevention and fluid administration for post-ERCP pancreatitis. Our review aims to consolidate guideline recommendations and high-quality studies published in recent years to guide the management of AP and highlight areas in need of research.

Recent advances in understanding and managing acute pancreatitis

This review highlights advances made in recent years in the diagnosis and management of acute pancreatitis (AP). We focus on epidemiological, clinical, and management aspects of AP. Additionally, we discuss the role of using risk stratification tools to guide clinical decision making. The majority of patients suffer from mild AP, and only a subset develop moderately severe AP, defined as a pancreatic local complication, or severe AP, defined as persistent organ failure. In mild AP, management typically involves diagnostic evaluation and supportive care resulting usually in a short hospital length of stay (LOS). In severe AP, a multidisciplinary approach is warranted to minimize morbidity and mortality over the course of a protracted hospital LOS. Based on evidence from guideline recommendations, we discuss five treatment interventions, including intravenous fluid resuscitation, feeding, prophylactic antibiotics, probiotics, and timing of endoscopic retrograde cholangiopancreatography (ERCP) in acute biliary pancreatitis. This review also highlights the importance of preventive interventions to reduce hospital readmission or prevent pancreatitis, including alcohol and smoking cessation, same-admission cholecystectomy for acute biliary pancreatitis, and chemoprevention and fluid administration for post-ERCP pancreatitis. Our review aims to consolidate guideline recommendations and high-quality studies published in recent years to guide the management of AP and highlight areas in need of research.

Hypothermia-Related Acute Pancreatitis

Acute pancreatitis (AP) is an inflammatory disease presenting from mild localized inflammation to severe infected necrotic pancreatic tissue. In the literature, there are a few cases of hypothermia-induced AP. However, the association between hypothermia and AP is still a myth. Generally, mortality from acute pancreatitis is nearly 3-6%. Here, we present a 40-year-old chronic alcoholic female who presented with acute pancreatitis induced by transient hypothermia. A 40-year-old chronic alcoholic female was hypothermic at 81°F on arrival which was improved to 91.7°F with warming blanket and then around 97°F in 8 h. Laboratory tests including complete blood count, lipid panel, and comprehensive metabolic panels were within the normal limit. Serum alcohol level was 0.01, amylase 498, lipase 1,200, ammonia 26, serum carboxyhemoglobin level 2.4, and β-HCG was negative. The entire sepsis workup was negative. During rewarming period, she had one episode of witnessed generalized tonic-clonic seizure. It was followed by transient hypotension. Fluid challenge was successful with 2 L of normal saline. Sonogram (abdomen) showed fatty liver and trace ascites. CAT scan (abdomen and pelvis) showed evidence of acute pancreatitis without necrosis, peripancreatic abscess, pancreatic mass, or radiopaque gallstones. The patient was managed medically and later discharged from the hospital on the 4th day as she tolerated a normal low-fat diet. In our patient, transient hypothermia from chronic alcohol abuse and her social circumstances might predispose to microcirculatory disturbance resulting in acute pancreatitis. Early and aggressive fluid resuscitation prevents complications.

Spleen and splenic vascular involvement in acute pancreatitis: an MRI study

Background

To investigate the spleen and splenic vascular involvement in acute pancreatitis (AP) and their correlations with the severity of AP using magnetic resonance imaging (MRI).

Methods

MRI of 239 patients with AP was retrospectively reviewed to assess splenic and splenic vascular complications, and the severity of AP. The severity of AP was graded by the MRI severity index (MRSI) and the New Revised Classification of AP 2012. The intravoxel incoherent motion (IVIM) parameters (D, D*, and f) of spleen were measured. Thirty-five subjects without pancreatic and splenic disorders were enrolled as controls for IVIM parameters.

Results

Among the 239 patients with AP, splenomegaly (16.7%), splenic infarction (0.4%), splenic vein thrombosis (4.2%), phlebitis (7.5%) and arteritis (4.2%) were observed. Splenic vascular involvement was positively correlated with the severity of AP based on both the MRSI and the New Revised Classification of AP 2012 (P<0.05). In the control and AP groups, the splenic f values were (0.164±0.074) vs. (0.210±0.095) (P=0.023) respectively. In AP patients with and without splenomegaly, f = (0.240±0.091) vs. (0.203±0.095) (P<0.001).

Conclusions

Splenic vascular involvement and splenomegaly were common in AP. The vascular involvement was associated with the severity of AP. This complication should be considered when severity and prognosis of AP are assessed. Quantitative analysis of the spleen with IVIM might be a useful imaging biomarker for splenic perfusion changes in AP, especially in those with splenomegaly.

Mannose-coated gadolinium liposomes for improved magnetic resonance imaging in acute pancreatitis

Background

Acute pancreatitis (AP) is an acute inflammatory condition of the pancreas. The symptoms, treatment, and prognosis of mild and severe AP are different, and severe AP is a potentially life-threatening disease with a high incidence of complications and high mortality rate. Thus, it is urgent to develop an effective approach to reliably discriminate between mild and severe AP.

Methods

We have developed novel gadolinium-diethylenetriaminepentaacetic (Gd-DTPA)-loaded mannosylated liposomes (named thereafter M-Gd-NL) that preferably target macrophages in AP. The targeting ability of M-Gd-NL toward macrophages in AP and its ability to discriminate between mild and severe AP were evaluated.

Results

The liposomes were of desired particle size (~100 nm), Gd-DTPA encapsulation efficiency (~85%), and stability. M-Gd-NL and non-targeted Gd-DTPA-loaded liposomes (Gd-NL) exhibited increased relaxivity compared with Gd-DTPA. Compared with Gd-NL and Gd-DTPA, M-Gd-NL showed increased uptake in macrophages, resulting in increased T₁ imaging ability both in vitro (macrophage cell line) and in vivo (severe AP model). Importantly, M-Gd-NL had the ability to discriminate between mild and severe AP, as reflected by a significantly higher T₁ magnetic resonance imaging signal in severe AP than in mild AP. M-Gd-NL did not show severe organ toxicity in rats.

Conclusion

Our data suggest that M-Gd-NL had enhanced magnetic resonance imaging ability by targeting macrophages in AP and good ability to discriminate between mild and severe AP. We believe that M-Gd-NL could shed new light on the diagnosis of AP in the near future.

Endoscopic Management of Pancreatic Fluid Collections

Pancreatic fluid collections (PFCs) may develop due to inflammation secondary to acute and/or chronic pancreatitis, trauma, surgery, or obstruction from solid or cystic neoplasms. PFCs can be drained percutaneously, surgically, or endoscopically with endoscopic ultrasound-guided cyst gastrostomy and/or transpapillary drainage through endoscopic retrograde cholangiopancreatography. There has been a paradigm shift in the endoscopic management of PFCs in the past few years with newer techniques including utilization of self-expanding metal stents and multiport devices. This review is a comprehensive update on the classification of PFC, indications for drainage, optimal approach, and techniques.

Role of Clinical, Biochemical, and Imaging Parameters in predicting the Severity of Acute Pancreatitis

AIM

The assessment of the severity of acute pancreatitis (AP) is important for proper management of the disease and for its prognosis. The aim was to correlate clinical, biochemical, and imaging diagnostic parameters and evaluate their prognostic values in the early assessment of severity of AP.

MATERIALS AND METHODS

We prospectively studied 128 consecutive patients with AP. The predictors were clinical, biochemical, and imaging diagnostic parameters. The outcome measure was the occurrence of complications. Abdominal sonogram, contrast-enhanced computer tomography, and pancreatitis-specific clinical and laboratory findings were done.

RESULTS

According to the Atlanta classification, 84 patients (65.6%) had mild and 44 (34.4%) had severe AP. The severity markers were significantly different between the mild and the severe groups (p < 0.001). Leukocyte count, serum albumin level, C-reactive protein (CRP), Ranson, acute physiology and chronic health evaluation II (APACHE II), and Glasgow score were the factors associated with radiological severity grade. Leukocyte count, CRP, Ranson score, APACHE II, and Glasgow score were the factors associated with the number and appearance of acute fluid collections (AFCs). A significant association was found between the number of AFCs and the occurrence of complications [odds ratio 4.4; 95% confidence interval 2.5-7.6]. Hospital stay was significantly longer in the group with severe disease as compared with the group with mild disease (p < 0.001).

CONCLUSION

Clinical, biochemical, and imaging diagnostic parameters are related to the clinical course of AP and they can predict its severity. This allows us to determine the severity of the disease and to target the patients with high scores for close monitoring and more aggressive intervention.How to cite this article: Zerem D, Zerem O, Zerem E. Role of Clinical, Biochemical, and Imaging Parameters in predicting the Severity of Acute Pancreatitis. Euroasian J Hepato-Gastroenterol 2017;7(1):1-5.

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.

Preliminary Study of MR Diffusion Tensor Imaging of Pancreas for the Diagnosis of Acute Pancreatitis

OBJECTIVES

To evaluate the feasibility of differentiating between acute pancreatitis (AP) and healthy pancreas using diffusion tensor imaging (DTI) and correlate apparent diffusion coefficient (ADC) /fractional anisotropy (FA) values with the severity of AP.

MATERIAL AND METHODS

66 patients diagnosed with AP and 20 normal controls (NC) underwent DTI sequences and routine pancreatic MR sequences on a 3.0T MRI scanner. Average ADC and FA values of the pancreatic were measured. Differences of FA and ADC values between the AP group and the NC group with AP and healthy pancreas were compared by two-sample independent t-test. The severity of AP on MRI was classified into subgroups using MR severity index (MRSI), where the mean FA and ADC values were calculated. Relationship among the FA values, ADC values and MRSI were analyzed using Spearman's rank correlation coefficients.

RESULTS

The pancreatic mean ADC value in the AP group (1.68 ± 0.45×10-3mm2/s) was significantly lower than in the NC group (2.09 ± 0.55×10-3mm2/s) (P = 0.02); the same as mean FA value (0.39 ± 0.23 vs 0.54 ± 0.12, P = 0.00). In the subgroup analysis, the pancreatic ADC and FA value of edema AP patients was significantly higher than necrosis AP patients with P = 0.000 and P = 0.001respectively. In addition, as severity of pancreatitis increased according to MRSI, lower pancreatic ADC (r = -0.635) and FA value (r = -0.654) were noted.

CONCLUSION

Both FA and ADC value from DTI can be used to differentiate AP patients from NC. Both ADC and FA value of pancreas have a negative correlation with the severity of AP.

Management of acute pancreatitis (AP) - Polish Pancreatic Club recommendations

The presented recommendations concern the current management of acute pancreatitis. The recommendations relate to the diagnostics and treatment of early and late phases of acute pancreatitis and complications of the disease taking into consideration surgical and endoscopic methods. All the recommendations were subjected to voting by the members of the Working Group of the Polish Pancreatic Club, who evaluated them every single time on a five-point scale, where A means full acceptance, B means acceptance with a certain reservation, C means acceptance with a serious reservation, D means rejection with a certain reservation and E means full rejection. The results of the vote, together with commentary, are provided for each recommendation.

Perfusion-CT--Can We Predict Acute Pancreatitis Outcome within the First 24 Hours from the Onset of Symptoms?

PURPOSE

Severe acute pancreatitis (AP) is still a significant clinical problem which is associated with a highly mortality. The aim of this study was the evaluation of prognostic value of CT regional perfusion measurement performed on the first day of onset of symptoms of AP, in assessing the risk of developing severe form of acute pancreatitis.

MATERIAL AND METHODS

79 patients with clinical symptoms and biochemical criteria indicative of acute pancreatitis (acute upper abdominal pain, elevated levels of serum amylase and lipase) underwent perfusion CT within 24 hours after onset of symptoms. The follow-up examinations were performed after 4-6 days to detect progression of the disease. Perfusion parameters were compared in 41 people who developed severe form of AP (pancreatic and/or peripancreatic tissue necrosis) with parameters in 38 consecutive patients in whom course of AP was mild. Blood flow, blood volume, mean transit time and permeability surface area product were calculated in the three anatomic pancreatic subdivisions (head, body and tail). At the same time the patient's clinical status was assessed by APACHE II score and laboratory parameters such as CRP, serum lipase and amylase, AST, ALT, GGT, ALP and bilirubin were compared.

RESULTS

Statistical differences in the perfusion parameters between the group of patients with mild and severe AP were shown. Blood flow, blood volume and mean transit time were significantly lower and permeability surface area product was significantly higher in patients who develop severe acute pancreatitis and presence of pancreatic and/or peripancreatic necrosis due to pancreatic ischemia. There were no statistically significant differences between the two groups in terms of evaluated on admission severity of pancreatitis assessed using APACHE II score and laboratory tests.

CONCLUSIONS

CT perfusion is a very useful indicator for prediction and selection patients in early stages of acute pancreatitis who are at risk of developing pancreatic and/or peripancreatic necrosis already on the first day of the onset of symptoms and can be used for treatment planning and monitoring of therapy of acute pancreatitis. Early suspicion of possible pancreatic necrosis both on the basis of scores based on clinical status and laboratory tests have low predictive value.

Necrotizing pancreatitis: diagnosis, imaging, and intervention

Acute necrotizing pancreatitis is a severe form of acute pancreatitis characterized by necrosis in and around the pancreas and is associated with high rates of morbidity and mortality. Although acute interstitial edematous pancreatitis is diagnosed primarily on the basis of signs, symptoms, and laboratory test findings, the diagnosis and severity assessment of acute necrotizing pancreatitis are based in large part on imaging findings. On the basis of the revised Atlanta classification system of 2012, necrotizing pancreatitis is subdivided anatomically into parenchymal, peripancreatic, and combined subtypes, and temporally into clinical early (within 1 week of onset) and late (>1 week after onset) phases. Associated collections are categorized as "acute necrotic" or "walled off" and can be sterile or infected. Imaging, primarily computed tomography and magnetic resonance imaging, plays an essential role in the diagnosis of necrotizing pancreatitis and the identification of complications, including infection, bowel and biliary obstruction, hemorrhage, pseudoaneurysm formation, and venous thrombosis. Imaging is also used to help triage patients and guide both temporizing and definitive management. A "step-up" method for the management of necrotizing pancreatitis that makes use of imaging-guided percutaneous catheter drainage of fluid collections prior to endoscopic or surgical necrosectomy has been shown to improve clinical outcomes. The authors present an algorithmic approach to the care of patients with necrotizing pancreatitis and review the use of imaging and interventional techniques in the diagnosis and management of this pathologic condition.

Diffusion-weighted magnetic resonance imaging indicates the severity of acute pancreatitis

PURPOSE

To test the use of diffusion-weighted magnetic resonance imaging (DW-MRI) to differentiate between different degrees of severity of acute pancreatitis (AP).

METHOD

Thirty-six patients who underwent DW-MRI and magnetic resonance cholangiopancreatography were divided into patients with mild AP (mAP, n = 15), patients with necrotizing AP (nAP, n = 8), and patients with a normal pancreas (nP, n = 15; controls). The pancreas was divided into head, body, and tail, and each segment was classified according to image features: pattern 1, normal; pattern 2, mild inflammation; and pattern 3, necrosis. Apparent diffusion coefficients (ADCs) were measured in each segment and correlated with clinical diagnoses.

RESULTS

A total of 108 segments was assessed (three segments per patient). Segments classified as pattern 1 in the nP and mAP groups showed similar ADC values (P = 0.29). ADC values calculated for the pancreatic segments grouped according to the different image patterns (1-3) were significantly different (P < 0.001). Comparisons revealed significant differences in signal intensity between all three patterns (P < 0.05).

CONCLUSIONS

DW-MRI was a compatible and safe image option to differentiate tissue image patterns in patients with mAP, nAP, and nP, mainly in those with contraindications to contrast-enhanced MRI (which is classically required for determining the presence of necrosis) or computed tomography. ADC measures allowed precise differentiation between patterns 1, 2, and 3.

Acute Pancreatitis: Revised Atlanta Classification and the Role of Cross-Sectional Imaging

OBJECTIVE

The 2012 revision of the Atlanta Classification emphasizes accurate characterization of collections that complicate acute pancreatitis: acute peripancreatic fluid collections, pseudocysts, acute necrotic collections, and walled-off necroses. As a result, the role of imaging in the management of acute pancreatitis has substantially increased.

CONCLUSION

This article reviews the imaging findings associated with acute pancreatitis and its complications on cross-sectional imaging and discusses the role of imaging in light of this revision.

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.

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.

Magnetic resonance imaging for the normal mesostenium and involvement of the mesostenium in acute pancreatitis

The main point of this paper is to study MRI findings of the normal mesostenium and the involvement of the mesostenium in acute pancreatitis and to discuss the relationship between the involvement of the mesostenium and the severity of acute pancreatitis. In clinical practice, the mesenterical involvement in acute pancreatitis was often observed on MRI in daily works, which was little recorded in the reported studies. We conducted the current study to assess the mesenterical involvement in acute pancreatitis with MRI. We found that the mesenterical involvement of acute pancreatitis patients is common on MRI. The mesenterical involvement has a positive correlation with the MR severity index and the Acute Physiology and Chronic Healthy Evaluation II scoring system. It has been shown that MR can be used to visualize mesenterical involvement, which is a supplementary indicator in evaluating the severity of acute pancreatitis and local and systemic complications.

The normal transverse mesocolon and involvement of the mesocolon in acute pancreatitis: an MRI study

Objective

To study the MRI findings of the normal transverse mesocolon and the involvement of the mesocolon in acute pancreatitis (AP) as well as the relationship between the involvement of the mesocolon and the severity of AP.

Materials and Methods

Forty patients without pancreatic disorders were retrospectively analyzed to observe the normal transverse mesocolon using MRI; 210 patients with AP confirmed by clinical and laboratory tests were retrospectively analyzed using MRI to observe transverse-mesocolon involvement (TMI). The severity of TMI was recorded as zero points (no abnormalities and transverse-mesocolon vessel involvement), one point (linear and patchy signal in the transverse mesocolon) or two points (transverse-mesocolon effusion). The AP severity was graded by the MRI severity index (MRSI) and the Acute Physiology And Chronic Healthy Evaluation II (APACHE II) scoring system. The correlations of TMI with MRSI and APACHE-II were analyzed.

Results

In a normal transverse mesocolon, the display rates of the middle colic artery, the middle colic vein and the gastrocolic trunk on MRI were 95.0%, 82.5% and 100.0%, respectively. Of the 210 patients with AP, 130 patients (61.9%) had TMI. According to the TMI grading, 40%, 39% and 20% of the patients were graded at zero, one and two points, respectively. TMI was strongly correlated with the MRSI score (r = 0.759, P = 0.000) and the APACHE-II score (r = 0.384, P = 0.000).

Conclusion

MRI could be used to visualize transverse-mesocolon involvement. The severity of TMI could reflect that of AP in the clinical setting and imaging. TMI might be a supplementary indicator of the severity of AP.

American College of Gastroenterology guideline: management of acute pancreatitis

This guideline presents recommendations for the management of patients with acute pancreatitis (AP). During the past decade, there have been new understandings and developments in the diagnosis, etiology, and early and late management of the disease. As the diagnosis of AP is most often established by clinical symptoms and laboratory testing, contrast-enhanced computed tomography (CECT) and/or magnetic resonance imaging (MRI) of the pancreas should be reserved for patients in whom the diagnosis is unclear or who fail to improve clinically. Hemodynamic status should be assessed immediately upon presentation and resuscitative measures begun as needed. Patients with organ failure and/or the systemic inflammatory response syndrome (SIRS) should be admitted to an intensive care unit or intermediary care setting whenever possible. Aggressive hydration should be provided to all patients, unless cardiovascular and/or renal comorbidites preclude it. Early aggressive intravenous hydration is most beneficial within the first 12-24 h, and may have little benefit beyond. Patients with AP and concurrent acute cholangitis should undergo endoscopic retrograde cholangiopancreatography (ERCP) within 24 h of admission. Pancreatic duct stents and/or postprocedure rectal nonsteroidal anti-inflammatory drug (NSAID) suppositories should be utilized to lower the risk of severe post-ERCP pancreatitis in high-risk patients. Routine use of prophylactic antibiotics in patients with severe AP and/or sterile necrosis is not recommended. In patients with infected necrosis, antibiotics known to penetrate pancreatic necrosis may be useful in delaying intervention, thus decreasing morbidity and mortality. In mild AP, oral feedings can be started immediately if there is no nausea and vomiting. In severe AP, enteral nutrition is recommended to prevent infectious complications, whereas parenteral nutrition should be avoided. Asymptomatic pancreatic and/or extrapancreatic necrosis and/or pseudocysts do not warrant intervention regardless of size, location, and/or extension. In stable patients with infected necrosis, surgical, radiologic, and/or endoscopic drainage should be delayed, preferably for 4 weeks, to allow the development of a wall around the necrosis.

Pancreatic duct patterns in acute pancreatitis: a MRI study

Objectives

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

Materials and Methods

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

Results

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

Conclusion

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

The revised Atlanta classification for acute pancreatitis: updates in imaging terminology and guidelines

Imaging of acute pancreatitis requires not only an understanding of the disease subtypes and the myriad of associated complications but also familiarity with the appropriate radiologic nomenclature as defined by the Atlanta symposium in 1992 and, more recently, by the Acute Pancreatitis Classification Working Group in 2008. The accurate description of the radiological findings plays a critical role in the evaluation and management of patients with acute pancreatitis, particularly those with severe disease. There have been increasing efforts to develop uniformity in the use of terminology used to define the radiologic findings in acute pancreatitis, in particular, the terminology for fluid collections, a common area of inconsistency and confusion. Terms such as "acute peripancreatic fluid collections," "acute post- necrotic fluid collections," "pseudocyst," and "walled-off pancreatic necrosis" are now recommended as they describe the evolution of fluid collections in patients with both interstitial and necrotizing pancreatitis and nonspecific terms such as "pancreatic abscess" and "phlegmon" are being abandoned. In this review we illustrate, with case examples, the standardized terminology used in the radiological and clinical description of acute pancreatitis, its severity, and complications with an emphasis on the role of ultrasound, computed tomography and magnetic resonance imaging. Different management options of the associated complications are also discussed. The use of standardized terminology will hopefully improve the communication between radiologists, gastroenterologists, and surgeons to facilitate treatment planning and will lead to enhanced outcomes for patients with acute pancreatitis as well as create uniformity for enrollment into research studies.

Prognostic value of acute fluid collections diagnosed by ultrasound in the early assessment of severity of acute pancreatitis

PURPOSE

To evaluate the prognostic value of acute fluid collections (AFC) diagnosed by conventional transabdominal ultrasound in the early assessment of severity acute pancreatitis (AP).

METHODS

We studied 128 consecutive patients with AP between March 2006 and March 2011. The predictor was the number of AFC. Outcome measure was the occurrence of complications. Abdominal sonogram, contrast-enhanced CT, and pancreatitis-specific clinical and laboratory findings were performed.

RESULTS

AFC were associated with complications (p < 0.0001), Balthazar grade (p = 0.004), Ranson score (p < 0.0001), and the majority of clinical, radiologic, and biochemical parameters for predicting complications of AP (p < 0.05). Univariate logistic regression also revealed significant association between the number of AFC and the occurrence of complications (OR 4.4; 95% CI 2.5-7.6). After the adjustment for covariates, AFC remained prognostic for complications and a cutoff point of >1 AFC was prognostic of their occurrence with 88% sensitivity and 82% specificity.

CONCLUSIONS

AFC are related to the clinical course of AP and can predict its severity

MRI of the pancreas: problem solving tool

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

Evaluation of the BISAP score in predicting severity and prognoses of acute pancreatitis in Chinese patients

The present study was to evaluate the accuracy of bedside index for severity in acute pancreatitis (BISAP) in predicting the severity and prognoses of acute pancreatitis (AP) in Chinese patients. Clinical data for 497 patients with AP were analyzed retrospectively to compare BISAP with acute physiology and chronic health evaluation II, Ranson, and computed tomography severity index scores in predicting the severity of AP and the occurrence of pancreatic necrosis, mortality, and organ failure in patients with severe AP (SAP) using the area under the receiver-operating characteristic curve. Of the 497 patients, 396 had mild AP and 101 had SAP. There were significant correlations between the scores of any two systems. BISAP performed similarly to other scoring systems in predicting SAP, as well as pancreatic necrosis, mortality, and organ failure in SAP patients, in terms of the area under the receiver-operating characteristic curve. BISAP score is valuable in predicting the severity of AP and prognoses of SAP in Chinese patients.

A systematic review and meta-analysis of diagnostic performance of imaging in acute cholecystitis

PURPOSE

To update previously summarized estimates of diagnostic accuracy for acute cholecystitis and to obtain summary estimates for more recently introduced modalities.

MATERIALS AND METHODS

A systematic search was performed in MEDLINE, EMBASE, Cochrane Library, and CINAHL databases up to March 2011 to identify studies about evaluation of imaging modalities in patients who were suspected of having acute cholecystitis. Inclusion criteria were explicit criteria for a positive test result, surgery and/or follow-up as the reference standard, and sufficient data to construct a 2 × 2 table. Studies about evaluation of predominantly acalculous cholecystitis in intensive care unit patients were excluded. Bivariate random-effects modeling was used to obtain summary estimates of sensitivity and specificity.

RESULTS

Fifty-seven studies were included, with evaluation of 5859 patients. Sensitivity of cholescintigraphy (96%; 95% confidence interval [CI]: 94%, 97%) was significantly higher than sensitivity of ultrasonography (US) (81%; 95% CI: 75%, 87%) and magnetic resonance (MR) imaging (85%; 95% CI: 66%, 95%). There were no significant differences in specificity among cholescintigraphy (90%; 95% CI: 86%, 93%), US (83%; 95% CI: 74%, 89%) and MR imaging (81%; 95% CI: 69%, 90%). Only one study about evaluation of computed tomography (CT) met the inclusion criteria; the reported sensitivity was 94% (95% CI: 73%, 99%) at a specificity of 59% (95% CI: 42%, 74%).

CONCLUSION

Cholescintigraphy has the highest diagnostic accuracy of all imaging modalities in detection of acute cholecystitis. The diagnostic accuracy of US has a substantial margin of error, comparable to that of MR imaging, while CT is still underevaluated.

Renal and perirenal space involvement in acute pancreatitis: An MRI study

OBJECTIVES

To study the prevalence and characteristics of renal and perirenal space involvement and its relation to the severity of acute pancreatitis (AP) using MRI.

METHODS

115 patients with AP who underwent MRI with the clinical kidney function test were retrospectively analyzed in this study. MRI sequences included conventional and diffusion weighted imaging (DWI) sequences. The renal and perirenal space involvement in AP was noted on MRI. The renal apparent diffusion coefficient (ADC) on DWI was measured for each kidney. The severity of AP on MRI was graded using MR severity index (MRSI). The relationships among the renal and perirenal space involvement on MRI, the renal ADC, MRSI and the results of the kidney function test were analyzed.

RESULTS

In the 115 patients with AP, the renal and perirenal space abnormalities detected included renal parenchymal abnormalities (0.8%), abnormalities of the renal collecting system (2.6%), renal vascular abnormalities (1.7%), thickened renal fascia (99%), perirenal stranding (62%) and perirenal fluid collection (40%). The prevalence of perirenal space abnormalities was correlated with the severity of AP based on MRSI (P<0.05). The renal ADC values were lower in patients with abnormal kidney function than in those without kidney injury (P<0.05). The prevalence of kidney function abnormalities was 9.4%, 32% and 100% in mild, moderate, and severe AP cases, respectively (P=0.00).

CONCLUSION

Perirenal space involvement is much more than renal parenchymal involvement in AP. The prevalence of perirenal space involvement in AP on MRI has a positive correlation with the severity of AP according to MRSI.

Diffusion MRI of acute pancreatitis and comparison with normal individuals using ADC values

The aim of this study was to retrospectively measure and compare pancreatic apparent diffusion coefficient (ADC) in patients with acute pancreatitis (AP) with aged matched controls who underwent diffusion weighted imaging (DWI). The institutional review board approved this retrospective Health Insurance Portability and Accountability Act compliant study with a waiver for informed consent. Pancreatic ADC values from 27 patients with a clinical diagnosis of AP and 38 normal age-matched controls evaluated with DWI (b = 0 and 800 mm(2)/s) were retrospectively and independently measured by two radiologists. The ADCs were compared between the groups and between each of the pancreatic segments in the normal group. Inter-observer reliability was calculated and receiver operating characteristic analysis was used to determine the sensitivity and specificity of DW imaging in the diagnosis of acute pancreatitis. P < 0.05 was considered statistically significant. The ICC for inter-observer reliability was 0.98 in the control and 0.97 in the AP group. The mean pancreatic ADC in the AP group (1.32 × 10(-3) mm(2)/s ± 0.13) was significantly lower than in the normal group (1.77 × 10(-3) mm(2)/s ± 0.32). There was no significant difference in mean ADCs between each of the pancreatic segments in the controls. A threshold ADC value of 1.62 × 10-3 mm(2)/s yielded a sensitivity of 93% and specificity of 87% for detecting acute pancreatitis for b values of 0 and 800 s/mm(2). Pancreatic ADCs are significantly lower in patients with AP than normal controls.