Optical Coherence Tomography of the Gastrointestinal Tract

Trial Information

Optical Coherence Tomography of the Gastrointestinal Tract

Protocol Summary The long term objective of the proposed research is to develop a high-speed
noninvasive endoscopic functional optical coherence tomography (F-OCT) device using
microelectromechanical system (MEMS) technology for early diagnosis of tumors or lesions in
gastrointestinal tracts.

Study Design All patients undergoing endoscopy at UCIMC CDDC and who meet eligibility
criteria will be candidates for enrollment in the protocol. Signed informed consent will be
obtained.

Standard of Care Procedure The patients will undergo the standard of care endoscopy.
Endoscopy is performed on a routine basis with conscious sedation or general anesthesia.
Digital images and video clips of the areas of interest will be captured in the usual
standard of care fashion.

Research Procedure The OCT probe will then be inserted through the biopsy channel of the
endoscope into the GI tract lumen and OCT images will be acquired of the lesions just prior
to biopsies (research procedure). In addition, OCT images will be taken of the surrounding
normal tissue.

Primary Endpoint The OCT images will be correlated to the specific biopsy site and biopsy
number.

OCT Device and Probe Optical coherence tomography (OCT) is an emerging imaging modality that
uses light to image turbid media such as living tissues, and has been successfully used to
generate high resolution (~10 micron) cross-sectional images of tissue microstructure in the
human retina and skin. OCT devices are now commercially available for ophthalmic and
dermatologic use, and several clinical reports on the use of OCT in the vascular system and
aerodigestive tract have been published as well.

The OCT device is an optical imaging instrument that combines a broadband low power near
infrared light source (non-laser) with an interferometer to produce cross-sectional optical
images of tissue to depths of 1-2 mm. OCT is already used commercially to image the retina
and skin. This study focuses on a device designed specifically for the aerodigestive tract.
The OCT probe has been designed to fit through the biopsy channel of standard endoscopes.
The probes are designed with three different types of mechanism. (1) The first mechanism
consists of a fiber optic with a micro lens and prism attached at the end to direct the
light to and from the tissue sample. Scanning is achieved by moving the fiber optic along
its axis using a linear motor. Longitudinal OCT imaging can be realized with this
mechanism. Similar probes are already used in our laryngoscopic OCT study. (2) The second
mechanism is achieved by a rotational MEMS motor, on which an angled mirror is attached to
direct the light to the side. Rotational imaging can be realized with this mechanism. (3)
The third mechanism is based on the silicon MEMS technology. The scanner is created with a
polysilicon micromirror driven by high frequency, thick single crystal silicon comb drives.
The high speed scanning probe is with large scan angles, excellent optical properties, high
precision, and long-term reliability. The overall cross-sectional diameter is approximately
3 mm to be able to fit into the biopsy channel of the endoscope. The OCT device will focus
the incident low-coherence light onto the tissue and collect backscattered coherent photons.
The endoscopists can then obtain cross sectional optical images of the tissue through
arbitrary planes of section.