High-resolution endoscopic imaging of the GI tract: a comparative study ofoptical coherence tomography versus high-frequency catheter probe EUS

Background: Both optical coherence tomography (OCT) and catheter probe EUS (CPEUS) are candidates for high-resolution imaging of the GI wall, but thei r potential roles in this clinical context have not been investigated. Methods: OCT and CPEUS were used to image normal-appearing portions of the GI tract at the same sites. CPEUS was performed with a 20-MHz or a new 30-M Hz catheter probe. Results: Forty-four histologically confirmed normal sites in 27 patients we re evaluated. With OCT, mucosa and muscularis mucosa were clearly seen at a ll sites. Except for stomach, OCT demonstrated the submucosa in all sites. OCT penetration ranged from 0.7 to 0.9 mm. Microscopic structures such as e sophageal glands, intestinal villi, colonic crypts, and blood vessels were easily identified. CPEUS penetration ranged from 10 mm to 20 mm, and 5 to 7 distinct layers were discernible. However, both mucosa and submucosa were seen as thin layers without microscopic detail. Conclusion: OCT resolution is superior to high-frequency CPEUS, but depth o f penetration is limited to mucosa and submucosa. OCT images the major stru ctural components of the mucosa and submucosa whereas CPEUS does not. Poten tially, OCT and high-frequency CPEUS may be complementary for clinical imag ing.