Su1331 Diagnostic Accuracy of Endoscopic Ultrasound Elastography for Differentiation of Benign Vs Malignant Pancreatic Masses: A Meta-Analysis

Su1331 Diagnostic Accuracy of Endoscopic Ultrasound Elastography for Differentiation of Benign Vs Malignant Pancreatic Masses: A Meta-Analysis

Abstracts Su1331 Diagnostic Accuracy of Endoscopic Ultrasound Elastography for Differentiation of Benign Vs Malignant Pancreatic Masses: A Meta-Analy...

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Abstracts

Su1331 Diagnostic Accuracy of Endoscopic Ultrasound Elastography for Differentiation of Benign Vs Malignant Pancreatic Masses: A Meta-Analysis Daniel Martin*2,1, Srinivas R. Puli2,1 1 Gastroenterology, Saint Francis Medical Center, Peoria, IL; 2 Gastroenterology, University of Illinois, Peoria, IL Background and Aim: The differentiation of solid pancreatic masses continues to be a significant challenge. Early detection of pancreatic cancer is essential to improve the poor prognosis associated with pancreatic cancer. Both Endoscopic Ultrasound and Magnetic Resonance Imaging offer diagnostic studies to detect masses but have poor differentiation of benign vs malignant masses. EUS elastography is a minimallyinvasive option that has been used with varying success to aid in distinguishing between benign and malignant pancreatic masses. A meta-analysis was conducted to assess the accuracy of EUS elastography in identifying malignant pancreatic masses. Methods: A literature search was conducted by searching PudMed and Embase databases. QUADAS criteria was used to evaluate the studies based on quality. Two reviewers independently extracted the information from the literature for conducting a 2x2 table. A random-effect model or a fixed-effect model was used to estimate the sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio. A summary receiver operating characteristic curve was also constructed. Results: Initial search identified 268 studies, of which 36 studies were selected and reviewed. 19 studies which met the inclusion and exclusion criteria were included in this meta-analysis. EUS elastography was compared to histology from FNA and resection as well as long-term clinical follow-up. The pooled sensitivity and specificity for the differentiation of malignant vs benign pancreatic masses were 96.30% (95% CI 94.90-97.40%) and 62.70% (95% CI 57.10-66.20%). The pooled positive and negative likelihood ratios were 2.58 (95% CI 2.05-3.27) and 0.08 (95% CI 0.05-0.12). The diagnostic odds ratio was 39.77 (95% CI 25.83-61.22). The results were similar using both the random-effect model and the fixed-effect model. The area under SROC (AUC) was 0.88. Conclusions: EUS elastography is a valuable, minimally-invasive method for differentiating between benign and malignant pancreatic masses. EUS elastography could prove to be an important adjunct to EUS-FNA in the diagnosis of pancreatic cancer.

Su1332 Endoscopic Ultrasound Imaging Techniques for the Assessment of Intravascular Thrombosis Related to Malignant Tumors Irina F. Cherciu*1, Elena Tatiana Cartana1, Daniela E. Burtea1, Mihaela Calita1, Anca Vilcea1, Daniela Mititelu1, John G. Karstensen2, Peter Vilmann2, Adrian Saftoiu1,2 1 Department of Gastroenterology, Research Center of Gastroenterology and Hepatology, University of Medicine and Pharmacy Craiova, ROMANIA, Craiova, Romania; 2Gastro Unit, Division of Endoscopy, Copenhagen University Hospital Herlev, Copenhagen, Denmark Introduction: Vascular thrombosis is a common complication among cancer patients being a significant cause of morbidity and mortality. Although transabdominal contrast-enhanced ultrasound is an established procedure associated with high sensitivity and specificity regarding the diagnosis of portal vein thrombosis, methods like contrast-enhanced endoscopic ultrasound (CE-EUS) and EUS elastography(EUSEG) have not been previously exploited in this direction, despite that the endoscope is placed in close proximity to major mediastinal and abdominal vessels, thereby increasing the chances for better visualization. Aim: To investigate the importance of systematic scanning of the vascular system of patients referred for pancreaticobiliary EUS, through EUS-EG and CE-EUS. Material and methods: Our retrospective study included 16 patients who were referred in the past 10 years to the Research Center of Gastroenterology and Hepatology Craiova, Romania, with unclear lesions of the pancreaticobiliary system for further EUS assessment, which showed also thrombosis of the portal venous system and/or its tributaries. The characteristics of the thrombi were analyzed by elastography colour-based qualitative method and CE-EUS with 4.8 mL SonoVueÒ(Bracco, Italy) as contrast enhancer. EUS fine-needle aspiration (EUS-FNA) was performed in all patients for the primary lesions but not in thrombi. Results: From the total number of patients with splanchnic vascular thrombosis, 62% of the patients were diagnosed with pancreatic malignancies. In these cases, we noticed a hard (low strain) EUS-EG appearance of the malignant thrombus similar with the primary lesion, while for the patients with benign lesions EUS-EG indicated a soft (high strain) appearance of the bland thrombus. The avascular appearance of bland thrombosis was visualized as a void in all vascular phases, but especially in the portal phase. The malignant thrombus had a similar enhancement pattern with the tumor of origin and showed rapid hyperenhancement in the arterial phase, followed by portal venous washout. Important peritumoral collateral circulation was observed in several cases while in a limited number of patients central or peripheral thrombus repermeabilization occurred. Conclusions: Differential diagnosis of benign and malignant thrombus plays an important role considering that most solid cancer increase the risk of bland thrombus formation with specific complications, while the presence of malignant thrombus at distance signals a metastatic process and advanced disease. For the differential diagnosis of

AB338 GASTROINTESTINAL ENDOSCOPY Volume 85, No. 5S : 2017

splanchnic vein thrombus, gray-scale EUS findings are not sufficient alone. Consequently, the systematic employment of methods like EUS-EG and CE-EUS seems to be valuable in assessing thrombus for additional EUS-FNA orientation. Further studies involving a larger patient cohort are however needed.

Su1333 Clinical Impact of Strain Histogram Real-Time Elastography in Combination With Contrast Harmonic Imaging Eus for the Differential Diagnosis of Focal Pancreatic Masses: A Multicentric Trial Adrian Saftoiu1, Ionut Madalin Costache*1, Erwan Bories2, Marc Giovannini2, Maria Petrone3, Paolo Giorgio Arcidiacono3, Andre Ignee4, Christoph F. Dietrich4, Julio Iglesias-Garcia5, Siyu Sun6, Carmen Popescus7, Sevastita Iordache1 1 Research Center of Gastroenterology and Hepatology, University of Medicine and Pharmacy Craiova, Craiova, Dolj, Romania; 2Endoscopic Unit, Paoli-Calmettes Institut, Marseille, France; 3Gastrointestinal Endoscopy Unit, Vita Salute San Raffaele University, Milan, Italy; 4Med. Klinik 2, Caritas-Krankenhaus Bad Mergentheim, Bad Mergentheim, Germany; 5Gastroenterology Unit, University Hospital, Santiago de Compostella, Spain; 6Gastroenterology Department, Shengjing Hospital of China Medical University, Shenyang, China; 7Cytology Laboratory, County Emergency Clinical Hospital, Craiova, Romania Background: Recent advances in endoscopic ultrasound (EUS) fine needle aspiration (FNA), as well as the development of real-time elastography (RTE) and contrastharmonic imaging (CHI), allowed a better characterization of focal pancreatic masses, with possible implications in the management of patients with negative EUSFNA and a strong suspicion of malignancy. For the differential diagnosis, mean strain histograms (SH) are considered a better parameter for semi-quantitative RTE-EUS. Likewise, CHI-EUS parameters can also be quantified during evaluation of both the early arterial and late venous phase. Material and methods: The study design was prospective, blinded and multicentric, comparing RTE-EUS and CHI-EUS for the characterization of focal pancreatic masses by using parametric measurements, in comparison with the gold standard represented by pathology. Patients were consecutively included in six tertiary centers during routine EUS examinations, with two loops of elastography and contrast-enhancement recorded in the embedded hard disk drive of the ultrasound system. Strain histograms were performed during RTE-EUS, with the values being reversed as opposed to our initially published data on hue histograms. Consequently, a cut-off of 80 was derived from previous multicentric trials (with lower values indicating low strain as a predictive factor of malignancy). CHI-EUS also allowed the focal masses to be classified as either hyper, isoor hypoenhanced in comparison with the normal pancreatic parenchyma (with hypoenhancement considered a predictive factor of malignancy). EUS-FNA was then performed in all patients, with a positive cytological diagnosis taken as a final proof of malignancy. The diagnoses obtained by EUS-FNA were further verified either by surgery or during a clinical follow-up of at least 6 months. Results: A total number of 97 consecutive patients with focal pancreatic masses were included in the multicentric study. Final diagnoses of these patients were of malignant tumours (70 patients, 72.2%) and benign lesions (27 patients, 27.8%). Based on previously defined cut-offs for mean strain histograms obtained during RTE-EUS, the values of sensitivity, specificity, positive predictive value, negative predictive value and accuracy were 100%, 29.6%, 78.65%, 100% and 80.41%, respectively. Corresponding values for CHI-EUS were 98,2%, 57,1%, 90,1%. 88,8% and 90%, respectively. Conclusion: The current study confirmed the results of previous studies and meta-analyses by using objective parametric tools for both RTE-EUS and CHI-EUS, indicating a complementary role for the differential diagnosis of focal pancreatic masses. Moreover, the best values for the receiver operating curves were obtained for a sequential clinical algorithm based on the initial use of elastography followed by contrast-enhancement.

Su1334 Eus-Fna in Surgically Proven Pancreatic Neuroendocrine Tumors: A Large Single Center Experience YongYan Cui*3, Lauren G. Khanna2, Anjali Saqi5, John Crapanzano5, James M. Mitchell5, Beth Schrope4, Frank G. Gress1, Michael D. Kluger4, Tamas Gonda1, Amrita Sethi1, John A. Chabot4, John M. Poneros1 1 Gastroenterology, NYP Columbia University Medical Center, New York, NY; 2New York University, New York, NY; 3Medicine, NYP Columbia University Medical Center, New York, NY; 4Surgery, NYP Columbia University Medical Center, New York, NY; 5Pathology, NYP Columbia University Medical Center, New York, NY Objectives: Pancreatic neuroendocrine tumors (pNET) are rare neoplasms, occurring in less than 1 out of 100,000 people per year and representing 1-2% of all pancreatic tumors. While resection is the only curative treatment for localized disease, it remains a debated management option as many low-grade and intermediate-

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