Comparison of EUS-guided Fine Needle Aspiration Technique: Negative-pressure Suction With Syringe vs. Capillary Sampling With Stylet Slow-pull Technique

EUS-guided fine needle aspiration (EUS-FNA) is a safe and effective method for diagnosing pancreatic and peripancreatic solid masses. The diagnostic accuracy of EUS-FNA has been reported to be 62-96%. There are two aspiration methods for obtaining specimens with EUS needle, application of a negative-pressure syringe and capillary sampling (without suction).

The former method is thought to increase cellularity of obtained specimen. However, a negative-pressure syringe can worsen the specimen quality by increasing the amount of bloody material in the specimen and damaging the tissue. Blood in the aspirate dilutes the sample and makes direct smears more difficult to interpret because clots form.

Meanwhile, the latter method might yield a small sample with a high diagnostic yield because of a decreased amount of sanguineous staining. Recently, EUS-guided fine needle biopsy with 22-gauge ProCore needle using capillary sampling while removing the stylet slowly for 40 sec during the to-and-fro movement of the needle (capillary sampling with style slow-pull technique) for pancreas biopsy was reported to provide significantly higher tissue adequacy compared to half- (5 mL) or full suction (10 mL) methods in animal study.

Therefore, we will perform the prospective randomized clinical trial comparing the diagnostic adequacy and accuracy of the specimens obtained by two different aspiration methods in EUS-FNA: negative-pressure suction with syringe (NPS) vs. capillary sampling with stylet slow-pull technique (CSS).

The primary end point of this study is to evaluate the difference of diagnostic accuracy between two aspiration methods. This study is a prospective randomized clinical trial. The needle used in this study is a conventional EUS-FNA needle (Echotip, Cook Medical, Winston-Salem, NC) approved by the FDA and Korea Food and Drug Administration (KFDA).