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BACKGROUND: Volumetric laser endomicroscopy (VLE) is an advanced imaging modality used in Barrett’s esophagus (BE) surveillance. VLE image interpretation is challenged by subtle grayscale image variation across a large amount of data. Training in VLE interpretation is not standardized. This study aims to determine if VLE training can be incorporated into a gastroenterology (GI) fellowship curriculum with the use of a self-directed module. METHODS: A standardized, self-directed training module (30 min) was created explaining the background and established VLE criteria for the diagnosis of BE dysplasia. A VLE image dataset was generated from a multicenter VLE database of targeted biopsies. GI trainees were asked to grade each image for the presence or absence of the following criteria (I) increased surface optical frequency domain imaging (OFDI) signal intensity and (II) atypical glands and provide a final diagnosis (dysplastic vs. non-dysplastic). Diagnostic performance was calculated and results compared to VLE expert interpretation using histology as the gold-standard. RESULTS: The dataset included 50 VLE images (10 high-grade dysplasia, 40 non-dysplastic BE). VLE images were reviewed in a randomized and blinded fashion by 5 GI trainees with no prior VLE experience and 5 experienced VLE users. Sensitivity, specificity and accuracy of GI trainees was 83.3% (95% CI: 71.5–91.7%), 59.0% (95% CI: 51.6–66.0%), and 64.8% (95% CI: 58.5–70.7%) compared to 80.0% (95% CI: 67.7–89.2%), 79.5% (95% CI: 73.0–85.0%), and 79.6% (95% CI: 74.1–84.4%) for VLE experts respectively. The difference in specificity and accuracy between the two groups were statistically significant with P

The safety and efficacy of radiofrequency ablation (RFA) in treatment of Barrett's esophagus (BE)-associated dysplasia has been well established. The effectiveness of focal and balloon RFA devices has not been compared. Therefore, the aim of our study was to assess the effectiveness of focal and balloon RFA devices in the treatment of BE by calculating absolute and percentage change in BE length with RFA therapy by comparing pre- and post-treatment BE length.This is a retrospective cross-sectional study of patients who underwent at least one treatment with either focal and/or balloon RFA devices who were identified from two tertiary centers. Patients' demographics, hiatal hernia, pre- and post-treatment BE length, prior use of endoscopic therapies and number of sessions were recorded.Sixty-one patients who had undergone 161 RFA treatment sessions met inclusion criteria. There was no significant difference in percentage change in BE length with greater number of RFA sessions. RFA with a focal device resulted in greater percentage reduction in BE length compared to the balloon system (73% vs. 39%, p 0.01). After adjusting for initial BE length, pre-treatment BE length, hernia status, prior endoscopic mucosal resection (EMR), prior RFA, and prior EMR/RFA sessions, RFA with a focal device at each session remained an independent predictor for a significant reduction in BE extent as compared to the balloon system.The focal RFA device alone was more effective in treatment of BE compared to the balloon system, with a greater reduction in extent of BE. The focal RFA device for endoscopic eradication therapy of BE should be considered the preferred technique.

Optimal teaching methods for disease recognition using probe-based confocal laser endomicroscopy (pCLE) have not been developed. Our aim was to compare in-class didactic teaching vs. self-directed teaching of Barrett's neoplasia diagnosis using pCLE.This randomized controlled trial was conducted at a tertiary academic center. Study participants with no prior pCLE experience were randomized to in-class didactic (group 1) or self-directed teaching groups (group 2). For group 1, an expert conducted a classroom teaching session using standardized educational material. Participants in group 2 were provided with the same material on an audio PowerPoint. After initial training, all participants graded an initial set of 20 pCLE videos and reviewed correct responses with the expert (group 1) or on audio PowerPoint (group 2). Finally, all participants completed interpretations of a further 40 videos.Eighteen trainees (8 medical students, 10 gastroenterology trainees) participated in the study. Overall diagnostic accuracy for neoplasia prediction by pCLE was 77 % (95 % confidence interval [CI] 74.0 % - 79.2 %); of predictions made with high confidence (53 %), the accuracy was 85 % (95 %CI 81.8 % - 87.8 %). The overall accuracy and interobserver agreement was significantly higher in group 1 than in group 2 for all predictions (80.4 % vs. 73 %; P = 0.005) and for high confidence predictions (90 % vs. 80 %; P 0.001). Following feedback (after the initial 20 videos), the overall accuracy improved from 73 % to 79 % (P = 0.04), mainly driven by a significant improvement in group 1 (74 % to 84 %; P 0.01). Accuracy of prediction significantly improved with time in endoscopy training (72 % students, 77 % FY1, 82 % FY2, and 85 % FY3; P = 0.003).For novice trainees, in-class didactic teaching enables significantly better recognition of the pCLE features of Barrett's esophagus than self-directed teaching. The in-class didactic group had a shorter learning curve and were able to achieve 90 % accuracy for their high confidence predictions.

Background The optimal method for teaching NBI International Colorectal Endoscopic (NICE) criteria to medical trainees is unknown. Methods Trainees (medical students, residents, and gastroenterology fellows) were randomized to 2 groups (in-classroom vs. self-directed training). Teaching phase: A standardized presentation was developed about narrow band imaging (NBI) and NICE criteria. The in-class teaching group attended a single live-teaching session (with NBI expert). The self-directed training group was provided with the same educational tool with recorded audio. Testing phase: All participants provided their predicted histology and their level of confidence. After completing initial 10 clips, the in-class teaching group received live feedback (NBI expert), whereas the self-teaching group received automated audio feedback. All participants then reviewed the next 30 NBI videos. The diagnostic performance of NBI in predicting histology was compared between the 2 groups. Results Twenty medical trainees (8 students, 8 residents, and 4 gastroenterology fellows) participated in the study. The overall accuracy, sensitivity, specificity, and negative predictive value in using NBI to predict histology were: 79.0% [95% confidence interval (CI), 76.2-81.8], 69.5% (95% CI, 65.0-74.0), 88.5% (95% CI, 85.3-91.6), and 74.4% (95% CI, 70.4-78.3). There were no significant differences in the performance characteristics between the in-classroom and self-directed groups for all responses including those answered with high confidence. Conclusions Using a standardized educational tool, the accuracy of distinguishing adenomatous versus hyperplastic colon polyps using NBI between the in-class teaching and self-directed learning were similar. This suggests that both training methods can be utilized for the education of medical trainees in the use of NICE criteria.

BACKGROUND Validated probe-based confocal endomicroscopy (pCLE) criteria for distinguishing hyperplastic polyps (HPs) and tubular adenomas (TA) have not yet been developed. AIM To develop pCLE criteria for distinguishing HP from TA and evaluate its performance characteristics among experts. METHODS pCLE criteria for colon polyp histology were developed and tested in 2 phases prospectively. Phase I: 8 preliminary criteria were developed and tested internally. Criteria achieving an accuracy of >75% (epithelial surface: regular vs. irregular; goblet cells: increased vs. decreased; gland axis: horizontal vs. vertical; gland shape: slit/stellate vs. villiform; image scale: gray vs. dark) were evaluated in Phase II of study wherein external assessors evaluated these criteria in a separate set of pCLE videos. Accuracy and interobserver agreement (95% confidence intervals) were determined for colon histology prediction. RESULTS Phase I (criteria development/internal testing): 8 criteria were assessed by 4 pCLE experts using 28 videos (14 HP/14 TA). Five of 8 pCLE criteria met selection for phase II (accuracy >75%). Phase II (external validation): 36 pCLE colon polyp videos (HP 16/TA 20) were evaluated by 8 external assessors. Overall accuracy in diagnosis of colon polyp histology was 84.9% (95% confidence interval, 81.7-87.7). Of predictions made with high confidence (75%), histology was predicted with an accuracy of 91%, sensitivity 83%, specificity 100%, negative predictive value 87% and positive predictive value 98%. Interobserver agreement was substantial (κ=0.73). CONCLUSIONS We demonstrate the development and validation of pCLE criteria for prediction of colon polyp histology. Using these criteria, overall accuracy in differentiating TA from HP was high with substantial interobserver agreement.

It is not clear whether length of Barrett's esophagus (BE) is a risk factor for high-grade dysplasia (HGD) or esophageal adenocarcinoma (EAC) in patients with nondysplastic BE. We studied the risk of progression to HGD or EAC in patients with nondysplastic BE, based on segment length.We analyzed data from a large cohort of patients participating in the BE Study-a multicenter outcomes project comprising 5 US tertiary care referral centers. Histologic changes were graded as low-grade dysplasia, HGD, or EAC. The study included patients with BE of documented length without dysplasia and at least 1 year of follow-up evaluation (n = 1175; 88% male), and excluded patients who developed HGD or EAC within 1 year of their BE diagnosis. The mean follow-up period was 5.5 y (6463 patient-years). The annual risk of HGD and EAC was plotted in 3-cm increments (≤3 cm, 4-6 cm, 7-9 cm, 10-12 cm, and ≥13 cm). We calculated the association between time to progression and length of BE.The mean BE length was 3.6 cm; 44 patients developed HGD or EAC, with an annual incidence rate of 0.67%/y. Compared with nonprogressors, patients who developed HGD or EAC had longer BE segments (6.1 vs 3.5 cm; P.001). Logistic regression analysis showed a 28% increase in risk of HGD or EAC for every 1-cm increase in BE length (P = .01). Patients with BE segment lengths of 3 cm or shorter took longer to develop HGD or EAC than those with lengths longer than 4 cm (6 vs 4 y; P = nonsignificant).In patients with BE without dysplasia, length of BE was associated with progression to HGD or EAC. The results support the development of a risk stratification scheme for these patients based on length of BE segment.

Pancreatic fistula is a known complication of distal pancreatectomy. Endotherapy with pancreatic duct stent placement and pancreatic sphincterotomy has been shown to be effective in its management; however, experience of endotherapy in the management of this complication has not been extensively reported from the United States. Preoperative endoscopic retrograde cholangiopancreatography (ERCP) with pancreatic stent placement has also been proposed to prevent this complication after distal pancreatectomy. In our cohort of 59 patients who underwent distal pancreatectomy, 13 (22%) developed a pancreatic fistula in the immediate postoperative period, of whom 8 (14%) patients (5 female, mean age 52 years) were referred for an ERCP because of ongoing symptoms related to the pancreatic fistula. The pancreatic fistula resolved in all patients after a median duration of 62 days from the index ERCP. The median number of ERCPs required to document resolution of the pancreatic fistula was 2. Although a sizeable percentage of patients develop a pancreatic fistula after distal pancreatectomy, only a small percentage of patients require ERCP for management of this complication. Given the high success rate of endotherapy in resolving pancreatic fistula and the fact that the majority of patients who undergo distal pancreatectomy never require an ERCP, performing ERCP for prophylactic pancreatic duct stent prior to distal pancreatectomy might not be necessary.

Esophageal cancer carries a poor prognosis among gastrointestinal malignancies. Although esophageal squamous cell carcinoma predominates worldwide, Western nations have seen a marked rise in the incidence of esophageal adenocarcinoma that parallels the obesity epidemic. Efforts directed toward early detection have been difficult, given that dysplasia and early cancer are generally asymptomatic. However, significant advances have been made in the past 10 to 15 years that allow for endoscopic management and often cure in early stage esophageal malignancy. New diagnostic imaging technologies may provide a means by which cost-effective, early diagnosis of dysplasia allows for definitive therapy and ultimately improves the overall survival among patients.

Background & Aims Although several classification systems have been proposed for characterization of Barrett's esophagus (BE) surface patterns based on narrow-band imaging (NBI), none have been widely accepted. The Barrett's International NBI Group (BING) aimed to develop and validate an NBI classification system for identification of dysplasia and cancer in patients with BE. Methods The BING working group, composed of NBI experts from the United States, Europe, and Japan, met to develop a validated, consensus-driven NBI classification system for identifying dysplasia and cancer in BE. The group reviewed 60 NBI images of nondysplastic BE, high-grade dysplasia, and esophageal adenocarcinoma to characterize mucosal and vascular patterns visible by NBI; these features were used to develop the BING criteria. We then recruited adult patients undergoing surveillance or endoscopic treatment for BE at 4 institutions in the United States and Europe, obtaining high-quality NBI images and performing histologic analysis of biopsies. Experts individually reviewed 50 NBI images to validate the BING criteria, and then evaluated 120 additional NBI images (not previously viewed) to determine whether the criteria accurately predicted the histology results. Results The BING criteria identified patients with dysplasia with 85% overall accuracy, 80% sensitivity, 88% specificity, 81% positive predictive value, and 88% negative predictive value. When dysplasia was identified with a high level of confidence, these values were 92%, 91%, 93%, 89%, and 95%, respectively. The overall strength of inter-observer agreement was substantial (κ = 0.681). Conclusions The BING working group developed a simple, internally validated system to identify dysplasia and EAC in patients with BE based on NBI results. When images are assessed with a high degree of confidence, the system can classify BE with >90% accuracy and a high level of inter-observer agreement.

Inconclusive findings on abdominal computerized tomography (CT) scans such as "enlarged or prominent pancreas" are commonly reported; however, their clinical significance is not clearly understood. The objective was to evaluate the efficacy of endoscopic ultrasound (EUS) in a cohort of patients with indeterminate findings on CT. We undertook a retrospective, single-center study at a tertiary care university hospital. About 107 consecutive patients (56 men) underwent EUS evaluation for inconclusive CT findings. The main intervention was EUS with fine needle aspiration (FNA) The main outcome measurement was to describe lesions identified by EUS in this cohort of patients. About 22 patients (21%) had pancreatic adenocarcinoma, 14 (13%) had chronic pancreatitis, 28 (26%) had benign lesions, and 35 patients (33%) had a normal EUS exam. Pancreatic cancer was more likely to be found on EUS in patients with significant weight loss (OR 10.1; 95% CI: 3.3-30.60), hyperbilirubinemia (OR 9; 95% CI: 3-26.0), or common bile duct (CBD) dilatation (OR 3.2; 95% CI: 1.25-8.5). The limitations of the study were that we were unable to control the uniformity of CT interpretation because the scans were reviewed by multiple radiologists. There were also limited follow-up data on patients who had benign lesions or normal EUS. In conclusion, EUS is an effective modality for evaluating pancreatic lesions in patients with inconclusive findings on abdominal CT. This assists in the prompt diagnosis and institution of appropriate treatment strategies for a variety of pancreatic diseases including cancer. In the setting of inconclusive CT findings, patients with hyperbilirubinemia, significant weight loss, or CBD dilatation should undergo EUS evaluation as they are at a higher risk of having underlying pancreatic cancer.

In the last 5-10 years, endoscopic ablative therapies have been gaining ground as treatment for Barrett's esophagus associated with high-grade dysplasia and early cancer, and they are becoming the most preferred technique over surgery as the standard of care. These therapies are associated with a lower rate of complications and mortality than surgery; studies have found them to be safe, effective and tolerable. Endoscopic ablative therapies are not, however, without their drawbacks. There is a paucity of data on long-term efficacy, and direct comparisons of the different modalities are lacking. Unlike surgery, current data suggest that endoscopic ablation treatments may not be curative in all patients, so patients require ongoing surveillance and acid suppression. Questions remain regarding durability as well as factors promoting recurrence after endoscopic therapy. The authors conducted a systematic review of the literature on ablative therapies in Barrett's esophagus to describe the modalities currently available and to provide an understanding of their limitations.

Background/Purpose: Visceral hypersensitivity for acid, extension and temperature stimuli in stomach and duodenum are involved in functional dyspepsia (FD). While the involvement of TRPV1 and TRPA1 have been reported in a number of animal experiments, data remains conflicting. On the other hand, ATP-gated ion channels, especially P2X3 receptor have recently been worthy of attention for its role in visceral hypersensitivity. We have reported that TRPV4 is expressed in esophageal, gastric and intestinal epithelia (J Physiol 2011, DDW2013, Am J Physiol 2013) and that ATP exocytosis is induced by TRPV4 activation in esophageal keratinocytes. We hypothesized that various physiological stimuli induced ATP release from gastric and duodenal (intestinal) epithelia through each different receptor and that excessive ATP release was involved in the pathophysiology of visceral hypersensitivity. METHODS: TRPV4 expression was examined in normal rat gastric epithelial cell line (RGE), human gastric cancer cell line (AGS) and rat intestinal cell line (IEC-6) by RT-PCR, immunostaining or Western blotting. ATP releases responding to various physiological stimuli (chemicals, low osmotic pressure, acid, extension, temperature) from each cell line were examined using luciferin-luciferase reaction. Acidic (pH 4.0), warm (40 °C) and standard (25 °C, pH7.4) solutions were used as acidic, warm stimuli or a control, respectively. Stretch stimuli was applied to cells cultured on a silicon chamber using a stretching apparatus (STREX Inc, Osaka, Japan). RESULTS: TRPV4 was expressed in RGE, IEC-6 but not in AGS. Specific TRPV4 agonist (GSK1016790A) or endogenous TRPV4 activator (5,6-EET) significantly enhanced ATP release from RGE cells but not AGS. Low osmotic, acidic, stretch or temperature stimuli significantly enhanced ATP release in RGE or IEC-6 cells. Stretchinduced ATP release from RGE cells was inhibited by pretreatment with a specific TRPV4 inhibitor, HC067047. Cell viability after each stimulus was confirmed by Trypan blue staining. Conclusion: Gastric and duodenal (intestinal) epithelial cells release ATP responding various physiological stimuli partially via TRPV4 activation . Excessive ATP release from epithelial cells might be involved in the pathophysiology of visceral hypersensitivity.

Mo1498 Learning Curve in Diagnosing Dysplasia in Barrett’s Esophagus (BE) Using Probe-Based Confocal LASER Endomicroscopy (pCLE): Results From a Randomized Controlled Trial Prashanth Vennalaganti*, Kavous Pakseresht, Benjamin R. Alsop, Sharad C. Mathur, Sravanthi Parasa, Benjamin Hornung, Neil Gupta, Prateek Sharma Gastroenterology and Hepatology, Veterans Affairs Medical Center, Kansas City, MO; Gastroenterology and Hepatology, University of Kansas Medical Center, Kansas City, KS; Gastroenterology, Loyola University Medical Center, Chicago, IL Background: With the advent of multiple novel techniques, optimal methods to teach advanced imaging techniques like pCLE have not yet been developed. There are limited data regarding the learning curve for trainees for using pCLE in diagnosing BE associated neoplasia. Aim: To determine the learning curve of medical trainees in diagnosing BE associated neoplasia using pCLE. Methods: Videos from a previously conducted multicenter trial evaluating the utility of pCLE in BE were used for this study. Study participants (GI fellows and medical students) with no previous pCLE experience were randomized to either in-class didactic or selfdirected teaching groups stratified by level of training. A standardized power point presentation was developed explaining the technology, the disease state and using previously published validated criteria for diagnosing dysplasia in BE: 1)epithelial surface: saw-toothed 2)goblet cells: sparse 3)glands: not equidistant 4)glands: unequal in size and shape 5)cells: enlarged 6)cells: pleomorphic. For in-class didactic group, an expert in pCLE conducted a classroom teaching session with an opportunity for interaction. Every study participant in the self-directed teaching group was provided with the same teaching power point but with recorded audio explaining the pCLE features to distinguish dysplastic and non-dysplastic BE. Following this initial training, all participants completed 1st set of 20 pCLE videos (pre-feedback) after which they reviewed correct responses with either the expert (in-class didactic group) or on audio power point (self teaching group). Finally, all participants completed next set of 40 videos (post-feedback) and marked their level of confidence in video interpretation for all assessments. Fisher’s exact test was used to calculate statistical differences between groups. Results:60 pCLE videos (nondysplastic BE 40 and dysplastic 20) were assessed by 18 study participants (10 GI fellows and 8 students). The overall accuracy of the entire group significantly improved from 73% to 79% post feedback (pZ0.04) (Table). This improvement was driven by overall improvement post feedback for the in-class didactic group (from 74% to 84%; p!0.01). Students had improvement in the proportion of predictions with high confidence (from 47% to 54.4% p 0.1) while fellows improved their pCLE accuracy in high-confidence predictions (from 82% to 91%, p 0.02) (Table). Finally, accuracy improved with years in endoscopy training (72.08% Students, 77.08% FY1, 82% FY2 and 85% FY3, p 0.003). Conclusions: Trainees taught by an in-class, didactic teaching session (overall 1 hour) had a shorter learning curve and achieved higher accuracies compared to self-directed learning group for the use of pCLE to diagnose BE associated neoplasia. In-class didactic teaching sessions should be the preferred method to teach pCLE for use in BE.

Background: With the advent of advanced imaging techniques like pCLE, education and teaching of criteria for disease recognition is critical; however, optimal training methods are unclear. Aim: To compare in-class didactic vs. self-directed teaching in diagnosing dysplastic and non-dysplastic BE using pCLE. Methods: pCLE videos from a previously conducted multicenter trial evaluating the utility of pCLE in BE patients were used for this study. Study participants (gastroenterology fellows and medical students) with no previous pCLE experience were randomized to in-class didactic teaching and self-directed teaching groups

visible lesions, 3) patients with HGD/EAC, and 4) number of HGD/EAC areas Methods: Data from a prospective, multi-center, randomized controlled trial evaluating the role of novel imaging techniques [High Definition White Light Endoscopy (HD-WLE), narrow band imaging (NBI), and probe based confocal endomicroscopy (pCLE)] were reviewed. As part of the protocol, coordinators at each study site recorded the time spent inspecting the BE mucosa using HD-WLE (Olympus 180 HD, with clear cap, no magnification) using a stop watch prior to biopsies being obtained. All visible lesions were described using the Paris classification system. To determine each patient's final histologic diagnosis, every patient was examined with HD-WLE, NBI, and pCLE. All suspicious areas as well as four quadrant random locations were biopsied then reviewed by a central pathologist. Fisher's exact test and an unpaired t-test were used to compare categorical and continuous variables, respectively. Results: 112 patients (mean age 65.5; 83.9% men, 100% Caucasian) with a mean BE length of 3.7cm were enrolled. The mean BIT with HD-WLE was 3.8min (SD 2.5min). 57 patients had a visible lesion seen on HD-WLE examination and 38 patients had a final diagnosis of HGD/EAC. Patients with a BIT with HD-WLE < 5 min were less likely to have a visible lesion (32.4% vs. 82.9%, p