Suboptimal Agreement Among Cytopathologists in Diagnosis of Malignancy Based on Endoscopic Ultrasound Needle Aspirates of Solid Pancreatic Lesions: A Validation Study.

BACKGROUND & AIMS: Despite the widespread use of endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) to sample pancreatic lesions and the standardization of pancreaticobiliary cytopathologic nomenclature, there are few data on inter-observer agreement among cytopathologists evaluating pancreatic cytologic specimens obtained by EUS-FNA. We developed a scoring system to assess agreement among cytopathologists in overall diagnosis and quantitative and qualitative parameters, and evaluated factors associated with agreement. METHODS: We performed a prospective study to validate results from our pilot study that demonstrated moderate to substantial inter-observer agreement among cytopathologists for the final cytologic diagnosis. In the first phase, 3 cytopathologists refined criteria for assessment of quantity and quality measures. During phase 2, EUS-FNA specimens of solid pancreatic lesions from 46 patients were evaluated by 11 cytopathologists at 5 tertiary care centers using a standardized scoring tool. Individual quantitative and qualitative measures were scored and an overall cytologic diagnosis was determined. Clinical and EUS parameters were assessed as predictors of unanimous agreement. Inter-observer agreement (IOA) was calculated using multi-rater kappa (κ) statistics and a logistic regression model was created to identify factors associated with unanimous agreement. RESULTS: The IOA for final diagnoses, based on cytologic analysis, was moderate (κ = 0.56; 95% CI, 0.43-0.70). Kappa values did not increase when categories of suspicious for malignancy, malignant, and neoplasm were combined. IOA was slight to moderate for individual quantitative (κ = 0.007; 95% CI, -0.03 to -0.04) and qualitative parameters (κ = 0.5; 95% CI, 0.47-0.53). Jaundice was the only factor associated with agreement among all cytopathologists on multivariate analysis (odds ratio for unanimous agreement, 5.3; 95% CI, 1.1-26.89). CONCLUSIONS: There is a suboptimal level of agreement among cytopathologists in the diagnosis of malignancy based on analysis of EUS-FNA specimens obtained from solid pancreatic masses. Strategies are needed to refine the cytologic criteria for diagnosis of malignancy and enhance tissue acquisition techniques to improve diagnostic reproducibility among cytopathologists.

A Prospective Multicenter Study Evaluating Learning Curves and Competence in Endoscopic Ultrasound and Endoscopic Retrograde Cholangiopancreatography Among Advanced Endoscopy Trainees: The Rapid Assessment of Trainee Endoscopy Skills Study.

BACKGROUND & AIMS: On the basis of the Next Accreditation System, trainee assessment should occur on a continuous basis with individualized feedback. We aimed to validate endoscopic ultrasound (EUS) and endoscopic retrograde cholangiopancreatography (ERCP) learning curves among advanced endoscopy trainees (AETs) by using a large national sample of training programs and to develop a centralized database that allows assessment of performance in relation to peers. METHODS: ASGE recognized training programs were invited to participate, and AETs were graded on ERCP and EUS exams by using a validated competency assessment tool that assesses technical and cognitive competence in a continuous fashion. Grading for each skill was done by using a 4-point scoring system, and a comprehensive data collection and reporting system was built to create learning curves by using cumulative sum analysis. Individual results and benchmarking to peers were shared with AETs and trainers quarterly. RESULTS: Of the 62 programs invited, 20 programs and 22 AETs participated in this study. At the end of training, median number of EUS and ERCP performed/AET was 300 (range, 155-650) and 350 (125-500), respectively. Overall, 3786 exams were graded (EUS, 1137; ERCP-biliary, 2280; ERCP-pancreatic, 369). Learning curves for individual end points and overall technical/cognitive aspects in EUS and ERCP demonstrated substantial variability and were successfully shared with all programs. The majority of trainees achieved overall technical (EUS, 82%; ERCP, 60%) and cognitive (EUS, 76%; ERCP, 100%) competence at conclusion of training. CONCLUSIONS: These results demonstrate the feasibility of establishing a centralized database to report individualized learning curves and confirm the substantial variability in time to achieve competence among AETs in EUS and ERCP. ClinicalTrials.gov: NCT02509416.

Comparison of FNA and fine-needle biopsy for EUS-guided sampling of suspected GI stromal tumors.

BACKGROUND AND AIMS: Subepithelial lesions are found in about 1% of all EGD procedures, and GI stromal tumors are a type of subepithelial lesion commonly encountered. Although the majority of subepithelial lesions are benign, GI stromal tumors have malignant potential, making a definitive diagnosis important. Currently, the criterion standard for the diagnosis of GI stromal tumors is EUS-directed FNA (EUS-FNA). The definitive diagnosis of GI stromal tumors relies on immunohistochemical staining, which depends on enough tissue being submitted to the pathologist. Achieving adequate tissue acquisition from suspected GI stromal tumors by EUS-FNA remains a limitation. Advancements in needle design, however, have improved tissue acquisition and therefore may improve the definitive diagnosis of GI stromal tumors by EUS-FNA. The goal of this study is to compare a fine-needle biopsy (FNB) needle (SharkCore, Medtronics) with FNA needles in definitively diagnosing suspected GI stromal tumors. METHODS: This is a retrospective, single-center study of consecutive patients with suspected GI stromal tumors by EUS characterization who underwent EUS-FNA or EUS-FNB. RESULTS: A total of 106 patients (53 men, mean [± standard deviation {SD}] age 62.19 ± 16.33 years) were included in the study undergoing EUS-FNA or EUS-FNB of suspected GI stromal tumors. The needle size that was used most often was 22 gauge in both groups. The average size of the lesions was 27.68 ± 15.70 mm; 71.7% of lesions were located in stomach, 19.8% in the esophagus, 5.7% in the duodenum, and 2.8% in the rectosigmoid colon. Ninety-one patients underwent EUS-FNA and 15 patients underwent EUS-FNB. Adequate tissue was procured, allowing immunohistochemical staining in 59 (64.8%) patients in the FNA group and 15 (100%) patients in the FNB group; P = .006. A diagnosis was reached by immunohistochemical staining in 48 (52.7%) patients in the FNA group and 13 (86.7%) patients in the FNB group; P = .01. Tissue was insufficient to make a cytologic diagnosis in 22 (24.2%) patients in the FNA group compared with none in the FNB group; P = .03. Adequate tissue was procured on the first pass of the FNB needle in the majority of patients (83.3%), whereas only 23.5% of patients had adequate tissue on the first pass by the FNA needle, with a median of 3 passes; P = .00. Tissue was insufficient to perform immunohistochemical staining, and thus a diagnosis could not be confirmed before surgery in 8 of the 34 surgical patients in the FNA group. Ten of 15 patients in the EUS-FNB group underwent surgery, all of whom were correctly diagnosed by FNB. There were no reported immediate adverse events or technical difficulties in either group. CONCLUSIONS: EUS-FNB by using a SharkCore needle for suspected GI stromal tumors is technically similar and equally safe as FNA, with better tissue acquisition, which was achieved with fewer needle passes and an improved diagnostic yield by immunohistochemical staining.

Per-oral video cholangiopancreatoscopy with narrow-band imaging for the evaluation of indeterminate pancreaticobiliary disease.

BACKGROUND AND AIMS: Cholangiopancreatoscopy for evaluating pancreaticobiliary pathology is currently limited by suboptimal optics. The aim of this study was to characterize the operating characteristics of per-oral video cholangiopancreatoscopy with narrow-band imaging (POVCP) findings in indeterminate pancreaticobiliary disease and to describe their association with neoplasia. METHODS: Data from consecutive patients undergoing POVCP for the evaluation of indeterminate pancreaticobiliary disease at a single tertiary care center were analyzed. Two experienced investigators had previously agreed on POVCP findings and terminology that were documented in endoscopy reports. Endoscopic procedural data from POVCPs performed between January 2006 and April 2015 and clinical data were abstracted from the endoscopic database and electronic medical records. Study endpoints included tissue-proven neoplasia or benign disease with ≥1 year of follow-up. RESULTS: A total of 109 patients were identified; 13 were excluded because of the presence of stone disease, known pancreaticobiliary malignancy, or presumed benign disease with ≤1 year of follow-up. Most patients (85%) underwent POVCP for biliary disease and 15% underwent POVCP for a pancreatic cause. Tortuous and dilated vessels (P < .001), infiltrative stricture (P < .001), polypoid mass (P = .003), and the presence of fish-egg lesions (P = .04) were found to be significantly associated with neoplasia. The overall POVCP impression had a high sensitivity (85%) and negative predictive value (89%) in assessing for the presence of neoplasia. CONCLUSIONS: Per-oral video cholangiopancreatoscopy is effective in the evaluation of indeterminate pancreaticobiliary disease. Tortuous and dilated vessels, infiltrative stricture, polypoid mass, and the presence of fish-egg lesions are significantly associated with neoplasia.

Endoscopic resection is cost-effective compared with laparoscopic resection in the management of complex colon polyps: an economic analysis.

BACKGROUND AND AIMS: Endoscopic resection (ER) is an efficacious treatment for complex colon polyps (CCPs). Many patients are referred for surgical resection because of concerns over procedural safety, incomplete polyp resection, and adenoma recurrence after ER. Efficacy data for both resection strategies are widely available, but a paucity of data exist on the cost-effectiveness of each modality. The aim of this study was to perform an economic analysis comparing ER and laparoscopic resection (LR) strategies in patients with CCP. METHODS: A decision analysis tree was constructed using decision analysis software. The 2 strategies (ER vs LR) were evaluated in a hypothetical cohort of patients with CCPs. A hybrid Markov model with a 10-year time horizon was used. Patients entered the model after colonoscopic diagnosis at age 50. Under Strategy I, patients underwent ER followed by surveillance colonoscopy at 3 to 6 months and 12 months. Patients with failed ER and residual adenoma at 12 months were referred for LR. Under Strategy II, patients underwent LR as primary treatment. Patients with invasive cancer were excluded. Estimates regarding ER performance characteristics were obtained from a systematic review of published literature. The Centers for Medicare & Medicaid Services (2012-2013) and the 2012 Healthcare Cost and Utilization Project databases were used to determine the costs and loss of utility. We assumed that all procedures were performed with anesthesia support, and patients with adverse events in both strategies required inpatient hospitalization. Baseline estimates and costs were varied by using a sensitivity analysis through the ranges. RESULTS: LR was found to be more costly and yielded fewer quality-adjusted life-years (QALYs) compared with ER. The cost of ER of a CCP was $5570 per patient and yielded 9.640 QALYs. LR of a CCP cost $18,717 per patient and yielded fewer QALYs (9.577). For LR to be more cost-effective, the thresholds of 1-way sensitivity analyses were (1) technical success of ER for complete resection in <75.8% of cases, (2) adverse event rates for ER > 12%, and (3) LR cost of <$14,000. CONCLUSIONS: Our data suggest that ER is a cost-effective strategy for removal of CCPs. The effectiveness is driven by high technical success and low adverse event rates associated with ER, in addition to the increased cost of LR.

Admission Hematocrit and Rise in Blood Urea Nitrogen at 24 h Outperform other Laboratory Markers in Predicting Persistent Organ Failure and Pancreatic Necrosis in Acute Pancreatitis: A Post Hoc Analysis of Three Large Prospective Databases.

OBJECTIVES: Predicting severe acute pancreatitis (AP) remains a challenge. The present study compares admission blood urea nitrogen (BUN), hematocrit, and creatinine, as well as changes in their levels over 24 h, aiming to determine the most accurate laboratory test for predicting persistent organ failure and pancreatic necrosis. METHODS: Clinical data of 1,612 AP patients, enrolled prospectively in three independent cohorts (University of Pittsburgh, Brigham and Women's Hospital, Dutch Pancreatitis Study Group), were abstracted. The predictive accuracy of the studied laboratories was measured using area under the receiver-operating characteristic curve (AUC) analysis. A pooled analysis was conducted to determine their impact on the risk for persistent organ failure and pancreatic necrosis. Finally, a classification tree was developed on the basis of the most accurate laboratory parameters. RESULTS: Admission hematocrit ≥44% and rise in BUN at 24 h were the most accurate in predicting persistent organ failure (AUC: 0.67 and 0.71, respectively) and pancreatic necrosis (0.66 and 0.67, respectively), outperforming the other laboratory parameters and the acute physiology and chronic health evaluation-II score. In a pooled analysis, admission hematocrit ≥44% and rise in BUN at 24 h were associated with an odds ratio of 3.54 and 5.84 for persistent organ failure, and 3.11 and 4.07, respectively, for pancreatic necrosis. In addition, the classification tree illustrated that when both admission hematocrit was ≥44% and BUN levels increased at 24 h, the rates of persistent organ failure and pancreatic necrosis reached 53.6% and 60.3%, respectively. CONCLUSIONS: Admission hematocrit ≥44% and rise in BUN at 24 h may be the optimal predictive tools in clinical practice among existing laboratory parameters and scoring systems.

Endoscopic and surgical treatment of malignant colorectal polyps: a population-based comparative study.

BACKGROUND: Long-term population-based data comparing endoscopic therapy (ET) and surgery for management of malignant colorectal polyps (MCPs) are limited. OBJECTIVE: To compare colorectal cancer (CRC)-specific survival with ET and surgery. DESIGN AND SETTING: Population-based study. PATIENTS: Patients with stage 0 and stage 1 MCPs were identified from the Surveillance Epidemiology and End Results (SEER) database (1998-2009). Demographic characteristics, tumor size, location, treatment modality, and survival were compared. Propensity-score matching and Cox proportional hazards regression models were used to evaluate the association between treatment and CRC-specific survival. INTERVENTIONS: ET and surgery. MAIN OUTCOME MEASUREMENTS: Mid-term (2.5 years) and long-term (5 years) CRC-free survival rates and independent predictors of CRC-specific mortality. RESULTS: Of 10,403 patients with MCPs, 2688 (26%) underwent ET and 7715 (74%) underwent surgery. Patients undergoing ET were more likely to be older white men with stage 0 disease. Surgical patients had more right-sided lesions, larger MCPs, and stage 1 disease. There was no difference in the 2.5-year and 5-year CRC-free survival rates between the 2 groups in stage 0 disease. Surgical resection led to higher 2.5-year (97.8% vs 93.2%; P < .001) and 5-year (96.6% vs 89.8%; P < .001) CRC-free survival in stage 1 disease. These results were confirmed by propensity-score matching. ET was a significant predictor for CRC-specific mortality in stage 1 disease (hazard ratio 2.40; 95% confidence interval, 1.75-3.29; P < .001). LIMITATIONS: Comorbidity index not available, selection bias. CONCLUSIONS: ET and surgery had comparable mid- and long-term CRC-free survival rates in stage 0 disease. Surgical resection is the recommended treatment modality for MCPs with submucosal invasion.

Comparison of existing clinical scoring systems to predict persistent organ failure in patients with acute pancreatitis.

BACKGROUND & AIMS: It is important to identify patients with acute pancreatitis who are at risk for developing persistent organ failure early in the course of disease. Several scoring systems have been developed to predict which patients are most likely to develop persistent organ failure. We head-to-head compared the accuracy of these systems in predicting persistent organ failure, developed rules that combined these scores to optimize predictive accuracy, and validated our findings in an independent cohort. METHODS: Clinical data from 2 prospective cohorts were used for training (n = 256) and validation (n = 397). Persistent organ failure was defined as cardiovascular, pulmonary, and/or renal failure that lasted for 48 hours or more. Nine clinical scores were calculated when patients were admitted and 48 hours later. We developed 12 predictive rules that combined these scores, in order of increasing complexity. RESULTS: Existing scoring systems showed modest accuracy (areas under the curve at admission of 0.62-0.84 in the training cohort and 0.57-0.74 in the validation cohort). The Glasgow score was the best classifier at admission in both cohorts. Serum levels of creatinine and blood urea nitrogen provided similar levels of discrimination in each set of patients. Our 12 predictive rules increased accuracy to 0.92 in the training cohort and 0.84 in the validation cohort. CONCLUSIONS: The existing scoring systems seem to have reached their maximal efficacy in predicting persistent organ failure in acute pancreatitis. Sophisticated combinations of predictive rules are more accurate but cumbersome to use, and therefore of limited clinical use. Our ability to predict the severity of acute pancreatitis cannot be expected to improve unless we develop new approaches.

Revised Atlanta and determinant-based classification: application in a prospective cohort of acute pancreatitis patients.

OBJECTIVES: Atlanta classification (Atlanta 1992) of acute pancreatitis (AP) has several limitations. Two new classification systems were recently proposed: the Atlanta reclassification (Atlanta 2012) and the determinant-based classification (DBC). The aim of our study was to: (i) determine the association between different severity categories and clinical outcomes and (ii) perform a head-to-head comparison between Atlanta 1992, Atlanta 2012, and DBC in predicting these clinical outcomes. METHODS: A total of 256 prospectively enrolled patients were assigned a severity category for all three classifications. Five clinical outcomes were evaluated: mortality, intensive care unit (ICU) admission and length of stay (LOS), need for interventions, and hospital LOS. Pairwise testing between severity grades within a classification system was performed using Fisher's exact and Kruskal-Wallis tests. Predictive accuracies were evaluated using area under the ROC curve (AUC) and Somer's D co-efficient. RESULTS: Overall, higher grades of severity were associated with worse clinical outcomes for all three classification systems. Atlanta 2012 and DBC performed better than Atlanta 1992 and were comparable in predicting mortality (AUC 0.89 for both vs. 0.76, P<0.001), ICU admission (AUC 0.91 for both vs. 0.80, P<0.001), and ICU LOS (Somer's D 0.21 and 0.28 vs. 0.07, P<0.05). DBC performed better in predicting need for interventions (AUC 0.93 vs. 0.85, P<0.001), whereas Atlanta 2012 performed better in predicting hospital LOS (Somer's D 0.43 vs. 0.37, P=0.04). CONCLUSIONS: Atlanta 2012 and DBC severity categories accurately reflected clinical outcomes in our cohort and were superior to Atlanta 1992. These novel classification systems can guide the selection of homogeneous patient populations for clinical research and provide an accurate spectrum of disease severity categories in the clinical setting.

Genetics of acute and chronic pancreatitis.

PURPOSE OF REVIEW: Acute pancreatitis, recurrent acute pancreatitis (RAP) and chronic pancreatitis are interrelated and progressive inflammatory disorders of the pancreas with highly variable and complex susceptibility, severity and outcomes. The role of genetics in acute pancreatitis, RAP and progression to chronic pancreatitis within a new framework is needed. RECENT FINDINGS: The first genome-wide association study in the pancreas has been published with genome-wide significance linked with noncoding variants at the PRSS1-PRSS2 locus on chromosome seven and the CLDN2 locus on the X chromosome. A new personalized medicine paradigm is being considered to facilitate organization of genetic and other susceptibility risk compared with the risk of disease progression or resolution and risk of complications. SUMMARY: A new framework for organizing multiple, complex data sets is emerging. The role of genetics in the context of other variables is important in understanding susceptibility to RAP and in the modification of disease severity and progression to chronic pancreatitis. Questions of when to order testing, what to order and how to use the data in real time remains an area for future research and development.

Lymphotoxin-alpha contributes to lymphangiogenesis.

Lymphotoxin-α (LTα), lymphotoxin-ß (LTß), and tumor necrosis factor-α (TNFα) are inflammatory mediators that play crucial roles in lymphoid organ development. We demonstrate here that LTα also contributes to the function of lymphatic vessels and to lymphangiogenesis during inflammation. LTα(-/-) mice exhibited reduced lymph flow velocities and increased interstitial fluid pressure. Airways of LTß(-/-) mice infected with Mycoplasma pulmonis had significantly more lymphangiogenesis than wild type (WT) or LTα(-/-) mice, as did the skin draining immunization sites of LTß(-/-) mice. Macrophages, B cells, and T cells, known sources of LT and TNFα, were apparent in the skin surrounding the immunization sites as were LTα, LTß, and TNFα mRNAs. Ectopic expression of LTα led to the development of LYVE-1 and Prox1-positive lymphatic vessels within tertiary lymphoid organs (TLOs). Quantification of pancreatic lymphatic vessel density in RIPLTαLTß(-/-) and WT mice revealed that LTα was sufficient for inducing lymphangiogenesis and that LTß was not required for this process. Kidneys of inducible LTα transgenic mice developed lymphatic vessels before the appearance of obvious TLOs. These data indicate that LTα plays a significant role in lymphatic vessel function and in inflammation-associated lymphangiogenesis.

Rectal Indomethacin Does Not Mitigate the Systemic Inflammatory Response Syndrome in Acute Pancreatitis: A Randomized Trial.

INTRODUCTION: Experimental data suggest that nonsteroidal antiinflammatory drugs may prevent disease severity and mortality in acute pancreatitis (AP). The aim of this study was to compare the efficacy of rectal indomethacin vs placebo in reducing the systemic inflammatory response syndrome (SIRS) score in a high-risk AP population for clinical progression. METHODS: We conducted a single-center, quadruple-blinded, randomized, placebo-controlled trial. Eligible criteria were subjects with AP and SIRS within 72 hours of presentation and those without organ failure. Subjects were allocated in a 1:1 ratio to indomethacin or placebo using simple randomization. Both interventions were administered rectally every 8 hours for 6 doses and compared using both intention-to-treat and per-protocol analyses. RESULTS: A total of 42 subjects (mean age 52 years, 55% men) were randomized to indomethacin (n = 18) or placebo (n = 24). There was no significant difference between the indomethacin and placebo groups in the change of SIRS score, proportion of subjects with SIRS, and distribution of SIRS scores at 24, 48, and 72 hours from randomization. There were no significant differences in the change of C-reactive protein levels at 48 hours or clinical outcomes between both treatment groups. Indomethacin was as safe as placebo, with 2 adverse events occurring in the placebo and none in the indomethacin arm. DISCUSSION: Rectal indomethacin can be safely administered over 48 hours; however, it is not superior to placebo in reducing the SIRS or clinical progression in a high-risk population with AP (ClinicalTrials.gov: NCT02692391).

Spontaneous bacterial peritonitis before liver transplantation does not affect patient survival.

BACKGROUND & AIMS: Spontaneous bacterial peritonitis (SBP) is a devastating complication of cirrhosis with high mortality. The impact of a prior episode of SBP on the outcome of liver transplantation (LT) is not well known. We aimed to determine the short- and long-term morbidity and mortality of patients who received LT, with and without a history of SBP. METHODS: We reviewed the records of all adult patients who underwent LT at a single center between June 1999 and June 2009. Patients with SBP were compared with all other patients who underwent LT during the same time period, without prior episodes of SBP. RESULTS: A total of 1491 adult patients underwent LT in the study period; 80 (5.4%) had at least 1 episode of SBP before LT. The mean follow-up time for all patients in the study was just over 4 years. Patients in the SBP cohort were more likely to be male (74%) and to have alcoholic liver disease. Patients with SBP had higher Child-Pugh and model for end-stage liver disease scores at the time of transplantation compared with controls, but there was no difference in long-term mortality between the 2 groups. Patients with SBP, however, were more likely to require surgery for complications related to LT within 1 year and were more likely to die of sepsis. CONCLUSIONS: Despite higher Child-Pugh and model for end-stage liver disease score at the time of LT, survival times of patients with SBP before LT are similar to those patients without SBP.

The -251 A/T Polymorphism in the IL8 Promoter is a Risk Factor for Acute Pancreatitis.

OBJECTIVES: Inflammation in the setting of acute pancreatitis (AP) is partially driven by pathogen recognition receptors that recognize damage-associated molecular patterns. Interleukin (IL)-8 is a chemotactic factor produced by pathogen recognition receptor-expressing cells. A single-nucleotide polymorphism in IL8 promoter region (-251 A/T) has been implicated in inflammatory diseases. We examined whether this IL8 polymorphism confers susceptibility to AP. METHODS: Patients with AP (n = 357) were prospectively recruited. Clinical data and blood were collected in subjects and controls (n = 347). Severity was defined following the Revised Atlanta Classification. Genotypes were assessed by quantitative polymerase chain reaction using TaqMan probes. RESULTS: Patients and controls had similar demographics and had no difference in Hardy-Weinberg (patients, P = 0.29; controls, P = 0.66). Twenty-five percent of patients developed severe AP. Compared with controls, the A/A genotype was more common in AP (P = 0.041; odds ratio, 1.42; 95% confidence interval, 1-1.99). Obese patients with the A/A genotype were more likely to develop mild AP (P = 0.047). CONCLUSIONS: The -251 polymorphism confers susceptibility to AP and disease severity in obese patients. However, its effect is moderate. One potential mechanism for this susceptibility is via increased IL8 production by innate cells, with subsequent enhanced neutrophil influx and pancreatic injury.

Dynamic imaging of lymphatic vessels and lymph nodes using a bimodal nanoparticulate contrast agent.

BACKGROUND: Evaluation of lymphedema and lymph node metastasis in humans has relied primarily on invasive or radioactive modalities. While noninvasive technologies such as magnetic resonance imaging (MRI) offer the potential for true three-dimensional imaging of lymphatic structures, invasive modalities, such as optical fluorescence microscopy, provide higher resolution and clearer delineation of both lymph nodes and lymphatic vessels. Thus, contrast agents that image lymphatic vessels and lymph nodes by both fluorescence and MRI may further enhance our understanding of the structure and function of the lymphatic system. Recent applications of bimodal (fluorescence and MR) contrast agents in mice have not achieved clear visualization of lymphatic vessels and nodes. Here the authors describe the development of a nanoparticulate contrast agent that is taken up by lymphatic vessels to draining lymph nodes and detected by both modalities. METHODS: A unique nanoparticulate contrast agent composed of a polyamidoamine dendrimer core conjugated to paramagnetic contrast agents and fluorescent probes was synthesized. Anesthetized mice were injected with the nanoparticulates in the hind footpads and imaged by MR and fluorescence microscopy. High resolution MR and fluorescence images were obtained and compared to traditional techniques for lymphatic visualization using Evans blue dye. RESULTS: Lymph nodes and lymphatic vessels were clearly observed by both MRI and fluorescence microscopy using the bimodal nanoparticulate contrast agent. Characteristic tail-lymphatics were also visualized by both modalities. Contrast imaging yielded a higher resolution than the traditional method employing Evans blue dye. MR data correlated with fluorescence and Evans blue dye imaging. CONCLUSION: A bimodal nanoparticulate contrast agent facilitates the visualization of lymphatic vessels and lymph nodes by both fluorescence microscopy and MRI with strong correlation between the two modalities. This agent may translate to applications such as the assessment of malignancy and lymphedema in humans and the evaluation of lymphatic vessel function and morphology in animal models.

Which Patients with Mild Acute Pancreatitis Require Prolonged Hospitalization?

OBJECTIVES: In our experience, a subset of mild acute pancreatitis (AP) patients, as defined by the Revised Atlanta Classification, has longer than expected hospitalization. Our aims are to report the prevalence of patients with mild AP who have a prolonged length of stay (LOS), evaluate the etiology, thoroughly phenotype, and finally compare this subset to those with expected LOS. METHODS: Patients admitted with AP from 2003 to 2015 were prospectively enrolled into this cohort study. LOS ≥8 days was considered as prolonged LOS. Data on demographics, clinical and laboratory variables, management, and outcomes was both prospectively and retrospectively collected. Continuous variables were compared using the nonparametric t-test (Wilcoxon's test) and categorical variables using the Pearson's χ2 test. RESULTS: Among 231 enrolled mild AP patients, 46 (20%) had a prolonged LOS (≥8 days). The main determinants of prolonged LOS included ongoing pancreatitis-related symptoms (n=31, 67.4%) and performance of cholecystectomy (n=11, 23.9%). When compared to patients with expected LOS (<8 days, n=185), patients with prolonged LOS due to ongoing symptoms (n=31) were more likely to have systemic inflammatory response syndrome at 48 h from admission (37% vs. 13.4%, P<0.001), a prolonged fasting period (6.6 vs. 2.8 days, P<0.001), and need for nutritional support (30% vs. 1.6%, P<0.001). CONCLUSIONS: About 20% of patients with mild AP have a longer than expected hospital stay, mostly attributed to ongoing pancreatitis-related symptoms. An early decision (at 72 h) for enteral nutrition support in these patients needs to be explored so as to shorten hospitalization and reduce cost of care.

Interobserver agreement among cytopathologists in the evaluation of pancreatic endoscopic ultrasound-guided fine needle aspiration cytology specimens.

BACKGROUND AND AIMS: Endoscopic ultrasound with fine needle aspiration (EUS-FNA) has become the standard of care in the evaluation of solid pancreatic lesions. Limited data exist on interobserver agreement (IOA) among cytopathologists in assessing solid pancreatic EUS-FNA specimens. This study aimed to evaluate IOA among cytopathologists in assessing EUS-FNA cytology specimens of solid pancreatic lesions using a novel standardized scoring system and to assess individual clinical and cytologic predictors of IOA. METHODS: Consecutive patients who underwent EUS-FNA of solid pancreatic lesions at a tertiary care referral center were included. EUS-FNA slides were evaluated by four blinded cytopathologists using a standardized scoring system that assessed final cytologic diagnosis and quantitative (number of nucleated/diagnostic cells) and qualitative (bloodiness, inflammation/necrosis, contamination, artifact) cytologic parameters. Final clinical diagnosis was based on final cytology, surgical pathology, or 1-year clinical follow-up. IOA was calculated using multi-rater kappa (κ) statistics. Bivariate analyses were performed comparing cases with and without uniform agreement among the cytopathologists followed by logistic regression with backward elimination to model likelihood of uniform agreement. RESULTS: Ninety-nine patients were included (49 % males, mean age 64 years, mean lesion size 26 mm). IOA for final diagnosis was moderate (κ = 0.45, 95 % confidence interval (CI) 0.4 - 0.49) with minimal improvement when combining suspicious and malignant diagnoses (κ = 0.54, 95 %CI 0.49 - 0.6). The weighted kappa value for overall diagnosis was 0.65 (95 %CI 0.54 - 0.76). IOA was slight to fair (κ = 0.04 - 0.32) for individual cytologic parameters. A final clinical diagnosis of malignancy was the most significant predictor of agreement [OR 3.99 (CI 1.52 - 10.49)]. CONCLUSIONS: Interobserver agreement among cytopathologists for pancreatic EUS-FNA specimens is moderate-substantial for the final cytologic diagnosis. The final clinical diagnosis of malignancy was the strongest predictor of agreement. These results have significant implications for patient management and need to be validated in future trials.