4918 Diagnosis of specialized intestinal metaplasia by optical coherence tomography.

Abstract

Introduction: Optical coherence tomography (OCT) is an optical imaging technique that produces high-resolution cross-sectional images of tissue in vivo near the level of histopathology. OCT is analogous to ultrasound imaging but uses infrared light rather than acoustic energy. Infrared light provides significantly better resolution (10 microns) than ultrasound.We have developed a catheter-based endoscopic OCT system to image the epithelium of the gastrointestinal tract. The aim of this study was to identify objective OCT image criteria for specialized intestinal metaplasia (SIM). Methods: OCT was used to image the stomach and esophagus of 75 patients undergoing routine upper endoscopy. Following endoscopic imaging the OCT catheter was inserted through the instrument channel of the endoscope. The endoscopic image was recorded simultaneously with the OCT images to provide accurate registration of the OCT image location. Following acquisition of several images at one location, a mucosal biopsy of the imaged site was performed. 158 biopsies were precisely correlated with their OCT images. OCT criteria for SIM were formulated by analyzing biopsy proven cases of SIM (n=72). These criteria were then retrospectively applied to all images of biopsy proven gastric, squamous, SIM, and cardiac epithelium to determine the sensitivity and specificity of OCT for SIM. Results: OCT images of SIM are characterized by (1) lack of the layered structure of normal squamous epithelium or the vertical pit and crypt morphology of normal gastric mucosa, (2) disorganized architecture with an inhomogeneous tissue contrast and an irregular mucosal surface, (3) presence of mucosal glands which can be identified as either pockets of low reflectance below the epithelial surface or invaginations through the epithelium. These OCT criteria were found to be 100% sensitive and 88% specific for SIM in the esophagus. All false positive images were secondary to cardiac epithelium. Conclusions: Objective OCT criteria are highly sensitive and specific for specialized intestinal metaplasia. We are currently enrolling patients in a prospective blinded trial of OCT to detect SIM at the gastroesophageal junction in patients without known Barrett's esophagus. OCT may eventually aid in the diagnosis and surveillance of this preneoplastic lesion.