EUS-Guided Fine-Needle Biopsy Protocol for Pancreatic Lesions

All procedures were performed with a linear array echoendoscope (EG-530UT2, Fujifilm Medical Systems, Tokyo, Japan or UCT 260, Olympus Medical Systems, Tokyo, Japan) by experienced endosonographers (M.J.Y, J.K, and S.W.P) with more than 100 cases of EUS-FNA or FNB per year under a well-established standard protocol^{7 (link)}. EUS-FNB was attempted with a biopsy needle (Franseen needle; Acquire; Boston Scientific (Fig. 1A) or Reverse-bevel needle; EchoTip ProCore; Cook Endoscopy (Fig. 1B)) or EUS-FNA with a Menghini-tip needle (EZ shot3, Olympus Medical Systems, Tokyo, Japan (Fig. 1C)) as directed by the characteristics and location of pancreatic tumors and endosonographer’s preference. Furthermore, the size of the needle used (22-gauge or 25-gauge) was chosen at the discretion of the endosonographers. After confirming the absence of intervening vasculature on the expected needle track using the color Doppler, a needle mounted with a stylet was used to create a puncture at either the stomach for body/tail lesions or the duodenum for head/uncinate process lesions. After puncturing the lesion, the stylet was withdrawn, and approximately 10–20 back-and-forth movements were performed within the lesion during each needle passage with continuous suction using a 10–20 mL syringe provided by the manufacturers. Detailly, 10 mL negative suction was applied to the Reverse-bevel needle, while 20 mL negative suction was applied to the EZ shot3 and Franseen needles. In addition, EUS-FNA or FNB was repeated until sufficient visible core tissue was obtained, although the optimal number of needle passes was decided at the discretion of the endosonographers^{8 (link)}. ROSE was not available in any institution.Figure 1

(A) The Franseen needle has a novel design of a crown tip with three-plane symmetric cutting edges. (B) The Reverse-bevel needle has a reversed-bevel system as a side-fenestrated opening on the needle shaft. (C) The Menghini-tip needle has a tapered bevel edge that facilitates the tissue being withdrawn into the lumen. Although it has a side port, it is classified as FNA needles because the side port of this needle system does not have any reinforcement geometries for cutting the tissue.