3459 High resolution endoscopic imaging using catheter probe endoscopic ultrasonography: a comparison of 20 mhz and 30 mhz cathter probes.

Abstract

Introduction: CPEUS has potential application in the endoscopic treatment of early stage cancers where it is important to clearly distinguish the muscularis mucosa from the submucosa. Also, CPEUS can image submucosal vessels which may have implications for guiding therapy for bleeding ulcers and endoscopic resection of large polyps. CPEUS using 20 MHz catheter probes shows the muscularis mucosa indistinctly and resolution is only sufficient to image larger vessels in the submucosa. Aim: To compare performance of the existing 20 MHz catheter probe (UMS 20R, Olympus)with a newly available 30 MHz catheter probe (XUM S30 25R, Olympus) in terms of image resolution and ability to identify muscularis mucosa and submucosal vessels. Methods: CPEUS was used to image normal appearing gastrointestinal wall at different anatomic sites in patients undergoing elective endoscopic procedures. For CPEUS imaging during EGD, a water filled balloon sheath was used. Images were videotaped and objectively rated in terms of image quality, number of layers seen, depth of penetration and identification of microscopic structures. Results: Twentyone histologically normal sites (5 each of esophageal, gastric, duodenal, colonic and 3 rectal sites) in 10 patients were examined with the 30 MHz catheter probe. Another 21 sites (5 esophageal, 4 gastric, 2 duodenal, 6 colonic and 4 rectal sites) in 17 patients were examined with the 20 MHz catheter probe. Average depth of penetration was significantly lower with the 30 MHz catheter probe (11 mm vs. 17 mm, p