New Methods & Materials
High-resolution endoscopic imaging of the GI tract using optical coherence tomography,☆☆

https://doi.org/10.1016/S0016-5107(00)70450-0Get rights and content

Abstract

Background: Optical coherence tomography (OCT) has demonstrated the microscopic structure of the gastrointestinal (GI) tract mucosa and submucosa in vitro. We evaluated a prototype OCT system and assessed the feasibility of OCT in the human GI tract. Methods: The 2.4 mm diameter prototype OCT probe, inserted through an endoscope, provides a 360-degree radial scan. Images (6.7 frames/sec) are displayed on a television monitor. Tissue contact is not required. In patients undergoing elective endoscopy, OCT images were obtained of normal mucosa (confirmed by biopsy). Results: Seventy-two sites were imaged (38 patients): esophagus (21), stomach (12), duodenum (11), terminal ileum (4), colon (15), and rectum (9). Varying the distance between the probe and the mucosal surface produced images of the GI wall of varying depth. When held about 1 mm above the mucosal surface, the images consisted of mucosal structures such as colonic crypts, gastric pits, and duodenal villi. With the probe held against the wall, the OCT image comprised several layers interpreted as mucosa, muscularis mucosae, and submucosa. Structures including blood vessels were evident within the submucosa. A probe with a 0.5 mm working distance to the focal point provided the best images. Reducing the frame rate to 4.0 per second facilitated image interpretation. Conclusions: OCT is feasible in the human GI tract and provides interpretable high-resolution images of mucosa and submucosa.

Section snippets

PATIENTS AND METHODS

Patients scheduled for elective endoscopy (upper endoscopy, flexible sigmoidoscopy, and colonoscopy) were eligible for enrollment in the study. Patients were excluded for the following reasons: age under 18 years, those undergoing endoscopy on an emergency basis (e.g., acute GI bleeding), inability to give informed consent, or a contraindication to endoscopy (e.g., severe cardiopulmonary disease). Informed consent for both endoscopy and participation in the study were obtained from patients.

RESULTS

The following anatomic sites were studied in 38 patients: esophagus (21), stomach (12), duodenum (11), terminal ileum (4), colon (15), and rectum (9). A total of 72 sites were imaged. Endoscopic biopsies obtained at all sites were interpreted as normal.

The prototype OCT probe was found to be fully compatible with standard upper endoscopes, sigmoidoscopes, and colonoscopes. The probe, as presently designed, cannot be used with a side-viewing instrument with a catheter elevator. There were no

DISCUSSION

The prototype OCT system offered excellent high-resolution cross-sectional images in the esophagus. Depth of penetration and image quality in the stomach, duodenum, and to a lesser degree the colon were not as good as in the esophagus. These difference might be related to optical properties intrinsic to each organ. Another possible explanation is that the esophagus is relatively easy to scan inasmuch as the OCT probe aligns naturally in the desired perpendicular orientation for scanning.

DISCLOSURE STATEMENT

Authors M.V.S. and A.M.R. have proprietary interests in the OCT catheter probe.

References (19)

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Supported by and performed in collaboration with the Olympus Optical Co., Ltd., Tokyo, Japan.

☆☆

Reprint requests: M. V. Sivak, Jr., MD, Division of Gastroenterology (Wearn 253), University Hospitals of Cleveland, 11100 Euclid Ave., Cleveland, OH 44106; fax: 216-844-7371.

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