Elsevier

Gastrointestinal Endoscopy

Volume 52, Issue 3, September 2000, Pages 400-403
Gastrointestinal Endoscopy

New Methods & Materials
Improved model for teaching interventional EUS☆

Presented at the Annual Meeting of the American Society for Gastrointestinal Endoscopy, New Orleans, Louisiana, May 18–20, 1998.
https://doi.org/10.1067/mge.2000.108408Get rights and content

Abstract

Background: A swine model was previously developed for teaching endoscopic ultrasound (EUS). The purpose of this study was to improve this model and develop a method for creating focal lesions for EUS imaging and intervention. Methods: Experiments were performed in farm pigs (Sus scrofa) under general anesthesia. Under real-time EUS guidance attempts were made to create a submucosal lesion and a focal mediastinal lesion, to perform EUS-guided fine-needle aspiration of the pancreas, and to confirm the site of injection during “sham” EUS-guided celiac block. Results: A hypoechoic, submucosal mass was created in the stomach, which was then imaged by EUS and punctured trans-gastrically. Injection of saline solution in the mediastinum created a pseudo-mediastinal lymph node. A needle was then advanced trans-esophageally into the mediastinum to mimic EUS-guided fine-needle aspiration of a mediastinal lymph node. Abdominal exploration of the pigs after euthanasia confirmed injection of the sham celiac block around the celiac ganglion. Conclusion: The swine model is not only useful for teaching normal EUS anatomy, but it may be a useful model for teaching EUS-guided intervention.

Section snippets

Methods

Experiments were performed in farm pigs (Sus scrofa) under general anesthesia. The pig esophagus was intubated with a linear array echoendoscope (FG 32 UA; Pentax Corp. Orangeburg, N.Y.). The technique has been previously described of esophageal intubation in a pig under general anesthesia with an endotracheal tube in place.3 After intubation of the esophagus, linear ultrasound anatomy was studied in the pig as previously described: GI wall, aorta, celiac artery, superior mesenteric artery,

Results

The 10% lipid emulsion injected into the gastric submucosa created an easily recognized, well-defined hypoechoic lesion in the submucosa that mimicked a submucosal hypoechoic mass as seen by EUS (Fig. 2).

. EUS view of hypoechoic submucosal mass created in the gastric wall by injecting a 10% lipid solution under EUS guidance. M, Mucosa; S, submucosa; MP, muscularis propria.

The echoendoscope was then moved away from the artificial submucosal mass so that it was no longer visible by endosonography.

Discussion

EUS has evolved from a purely diagnostic imaging procedure to a technology that allows EUS-guided interventional procedures. 4, 5, 6, 7, 8, 9 Because EUS imaging itself has a long learning curve, attempts have been made to develop a model for teaching both diagnostic and interventional EUS. 1, 2, 3 However, in previous studies, focal lesions that were suitable for EUS-guided imaging and intervention were difficult to create. The present study demonstrates the feasibility of creating artificial

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☆

Reprint requests: Manoop S. Bhutani, MD, FACP, FACG, Director, Center of Endoscopic Ultrasound, University of Florida, PO Box 100214, Gainesville, FL 32610-0214; fax 352-392-3618; e-mail: [email protected].

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Copyright © 2000 American Society for Gastrointestinal Endoscopy. Published by Mosby, Inc. All rights reserved.