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sFigure 1. The significant GMD differences between CD patients and HC. The brain areasmarked in red in the results with age, gender and weight as covariates represent thedisappeared areas when adding HAD as covariates; the brain areas marked in red in theresults with age, gender, weight and HAD as covariates represent the remained areas. A.CD patients showed significantly increased GMD compare with HC. B. CD patients showedsignificantly decreased GMD compare with HC. C. The decreased GMD in dmPFC, insulaand ACC showed a significant negative correlation with CD duration (month). Amyg,Amygdala; MTC, middle temporal cortex; PCUN, precuneus; PREC, precentral gyrus; r,correlation coefficient.

Figure 2 A. The significant cortical thickness differences between CD patients and HC. Thebrain areas marked in red in the results with age, gender and weight as covariates representthe areas abolished difference when adding HAD as covariate; the brain areas marked inred in the results with age, gender, weight and HAD as covariates represent the remainedareas. B. CD patients showed significantly decreased SV of bilateral thalamus compared withHC; The SV of right thalamus is significantly different among the three groups, the painand non-pain CD group both showed significantly decreased SV compare with HC. C. Thedecreased cortical thickness in insula and OFC showed a significant negative correlationwith CD duration. CMF, caudal middle frontal cortex; IPC, inferior parietal cortex; PREC,precentral gyrus; PSTS, postcentral gyrus; PTRI, pars triangularis; SFC, superior frontalcortex; TC, temporal cortex. *P<0.05, **P<0.01.

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Endoprothesis for an Innovative Treatment of Walled-off Pancreatic Necrosis:The "Diabolo" ExperienceSusana Lopes, Francisco Baldaque-Silva, Pedro Pereira, Filipe Vilas-Boas, ArmandoRibeiro, Guilherme Macedo

Endoscopic transluminal treatment of pancreatic fluid collections (PFC) is an effective alterna-tive to surgical treatment. Endosonography guided puncture allows the performance ofdrainage, irrigation or direct endoscopic necrosectomy (DEN). Minimally invasive drainageof pancreatic pseudocysts has been recently a proposed approach along with removal ofsolid necrotic components in walled-off pancreatic necrosis (WOPN). We report an innovativeendoscopic approach using a new fully covered, 40mm length, 10mm diameter, self expanda-ble metal stent (FCSEMS), with flared diameter at both ends to provide stability and minimizethe risk of migration, and a retrieval suture at the enteric end (Hanarostent® BCF, formDiabolo). In 6 patients, aged between 41 and 79 years old with WOPN post acute pancreatitis,EUS guided transgastric puncture was performed by using a 19-gauge needle (EchoTip CookEndoscopy) with further puncture site balloon dilation to 10mm, to allow DEN (2 perpatient) and stent placement. Technical success was defined as the correct placement ofFCSEMS and clinical success as resolution of fever and white blood cell count normalizationand complete shrinkage of fluid collection without surgery. In all 6 patients the insertionwas successful, stents were fully expanded, and complete drainage was achieved in 5-10days as controlled by CT scan. We conclude that the endoscopic approach, using theseFCSEMS is feasible and a safe and effective alternative to surgery, in the treatment of PFC,either in pancreatic pseudocysts or WOPN.

S-574AGA Abstracts

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Optical Spectroscopy Distinguishes Pancreatic Cancer From Non-MalignantPancreatic TissuesJames Scheiman, Robert H. Wilson, Malavika Chandra, Diane M. Simeone, Jeremy Taylor,Oliver E. Lee, William R. Lloyd, Seung Yup Lee, Mary-Ann Mycek

Pancreatic cancer has a five-year survival of only 6%; currently-employed diagnostic methodscannot reliably detect the disease in its early stages. Confirmation of chronic pancreatitis inthe absence of advanced disease may be very challenging as well. A more accurate methodfor pancreatic tissue diagnostics remains an unmet medical need . Methods: We havedeveloped a clinically-compatible optical spectroscopy technique, which was employed forthe first time to measure reflectance and fluorescence data from freshly-excised pancreatictissues (immediately following removal at surgery) from 18 patients (39 normal sites, 34chronic pancreatitis sites, 32 adenocarcinoma sites). A rigorous statistical analysis of thesedata provided tissue classification utilizing a novel hybrid mathematical algorithm. Duringsurgery on 6 additional patients, we collected optical data in vivo. Results: Our approachaccurately distinguished pancreatic cancer from normal and chronic pancreatitis (sensitivity =90.6%, specificity = 87.7%, positive predictive value = 76.3%, negative predictive value =95.5%). Combined reflectance and fluorescence data provided better classification accuracythan either technique individually, although using reflectance data alone provided nearlythe same accuracy (sensitivity = 90.6%, specificity = 84.9%, positive predictive value =72.5%, negative predictive value = 95.4%) as using reflectance and fluorescence together.Site-matched in vivo and ex vivo data agreed qualitatively and quantitatively. Quantifieddifferences between adenocarcinoma and normal tissues in vivo were consistent with theex vivo results. Conclusion: Our spectroscopy method can be used to interrogate pancreatictissues during minimally invasive endoscopic procedures, including endoscopic ultrasound-guided fine needle aspiration, which currently suffers from important limitations in diagnosticaccuracy. The technology reported here does not require the administration of exogenouscontrast agents to patients and the portable clinical device is constructed with componentsat a reasonable manufacturing cost. These promising results show that optical spectroscopyhas the potential to assist with improved diagnosis of pancreatic cancer and chronic pancre-atitis.

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Cumulative Gain of Successive EUS-FNA Passes and Predictors for Diagnosisof Malignancy in EUS-Guided FNA of Pancreatic Masses: Results From aMulticenter, Prospective Randomized Controlled TrialSachin Wani, Daniel Mullady, Dayna S. Early, Amit Rastogi, Brian T. Collins, Jeff F. Wang,Carrie Marshall, Sharon B. Sams, Roy D. Yen, Mona Rizeq, Maria M. Romanas, OzlemUlusarac, Brian C. Brauer, Srinivas Gaddam, Thomas G. Hollander, Lindsay Hosford,Sydney S. Johnson, Vladimir M. Kushnir, Stuart K. Amateau, Cara Kohlmeier, Riad R.Azar, Ananya Das, Norio Fukami, Raj J. Shah, Steven A. Edmundowicz

BACKGROUND: EUS-FNA plays an integral role in the diagnosis and staging of suspectedpancreatic cancer. There are limited data on the cumulative gain of successive EUS-FNApasses and predictors for diagnosing malignancy during EUS-FNA of pancreatic masses.AIMS: (i) To evaluate the cumulative gain of successive EUS-FNA passes in the diagnosisof malignancy and (ii) To evaluate predictors for the diagnosis of malignancy on EUS-FNAspecimens in patients with pancreatic masses undergoing EUS-FNA. METHODS: This is apost-hoc analysis of a multicenter, prospective RCT conducted at 3 tertiary referral centersin which consecutive patients (pts) with a solid pancreatic mass on imaging underwentrandomization for EUS-FNA with or without an on-site CyP. Number of FNA passes in theCyP+ arm was dictated by the on-site CyP based on adequacy +/- the ability to make adiagnosis; 7 passes were performed in the CyP- arm. EUS-FNA protocol was standardized.Final slides were reviewed by CyPs using standardized criteria for cytologic characteristicsand final cytologic diagnosis - overall and individual pass. Patient demographics and EUScharacteristics of pancreatic mass (size, location, shape, echogenicity, margins) were recorded.Discrete time analysis was used to model the proportional odds of diagnosis of malignancyby EUS-FNA and multivariate regression modeling using a manual backward eliminationprocess was performed. RESULTS: 241 pts (mean age 66 yrs, 62% males, 82% Caucasians)were enrolled with a total of 641 FNA passes. Location of the pancreatic mass was: head55%, neck 10%, 23% body and tail 13% with a mean diameter of 3.2cm (SD 1.3). Finalcytologic diagnosis was: malignant 177 (73%), suspicious 17 (7%), atypical 12 (5%), benign28 (12%) and inadequate 7 (3%). 405 of 641 FNA passes yielded the diagnosis of malignancy.On a per-patient analysis, there was no difference in the diagnostic yield of malignancybetween the CyP+ and CyP- groups (75.2% vs. 71.7%, p=0.45). On a per-pass level,independent predictors for cytologic diagnosis of malignancy found on multivariate analysisincluded: size of the pancreatic mass, shape, hypoechogenicity, slide cellularity (representativecells + in >25% of slides), lack of GI contamination (< 25% of slide), adequate specimen,and presence of on-site CyP during EUS-FNA (Table 1). Overall, half the number of ptsrequired up to 6 FNA passes to confirm diagnosis of malignancy. The 1st FNA pass hadgreatest odds of cytologic diagnosis compared to subsequent FNA passes (Table 2). CONCLU-SIONS: Results of this RCT demonstrate that the first EUS-FNA pass has the highest yieldfor diagnosing malignancy with diminishing returns on subsequent passes. This study definesEUS and cytologic characteristics associated with a diagnosis of malignancy during EUS-FNA of pancreatic masses. (Supported by the ACG Clinical Research Award)Table 1: Multivariate Analysis for Predictors of Cytologic Diagnosis of Malignancy