Prospective Study Comparing Methods of Obtainment of Specimen After EUS-FNA in Patients With Peri-pancreatic Mass

EUS-guided FNA has been proved to be a safe and useful method for tissue sampling of gastrointestinal track lesions and other organ lesions including mediastinal and intra-abdominal lymph nodes, pancreas and hepatobiliary tree. The usefulness of EUS-FNA depends on several factors. For example, experience of the endosonographers, adequate sampling, sample preparing, accurate interpretation by the cytopathologist and on-site cytopathology interpretation. However, in many hospitals, no cytopathologist can be present during EUS-FNA. Therefore, determining appropriate methods to obtain and prepare EUS-guided FNA are important to make correct a diagnosis without on-site cytopathologist. Suction with a self-retracting 10-mL syringe will likely bring in more cellularity but also more blood. Some endosonographers use no suction, others use constant suction. Usually specimen is expelled from a needle with pushing the stylet into the needle. But use of the stylet during EUS-FNA is difficult and time consuming process. Injecting air was not recommended, because of spraying out uncontrollably, increasing risk of air artifact and specimen clotting. However, there is no further study which one is the appropriate, suction or no suction and pushing the stylet or injecting air until now. The hypothesis and aim of the prospective randomized controlled trials are as follows: First hypothesis: There was no difference in the adequacy, cellularity, bloodiness, contamination, air artifact in specimen obtained by each methods, suction or no suction and pushing the stylet or injecting air. Aim #1 : To compare the adequacy, cellularity, bloodiness, contamination, air artifact in specimen obtained by each methods, suction or no suction and pushing the stylet or injecting air. Second hypothesis: There was no difference in sensitivity, specificity, diagnostic accuracy, positive predictive value, negative predictive value and statistical agreement in specimen obtained by each methods, suctio