# TRD3: Endoscopic and Probe-based Coherence Imaging

> **NIH NIH P41** · MASSACHUSETTS GENERAL HOSPITAL · 2022 · $319,160

## Abstract

Project Summary
TRD 3
The goal of this TRD project is to enhance the power and functionality of endoscopic and probe-based OCT.
The small form factor of fiber-optic OCT probes affords the capacity to reach remote organs of the human
body, enabling OCT to be routinely used for clinical investigation of the coronary arteries, the gastrointestinal
tract, and the lung. However, many strategies to improve image contrast through advanced OCT signal
collection and processing are incompatible with the spatial and practical constraints of probe-based OCT. This
impairs diagnostic performance and feedback to guide interventions. The focus of TRD 3 is to address some of
these limitations.
OCT derives image contrast from variations in the tissue’s backscattering properties, but subtle differences in
the scattering properties can be difficult to identify because the signal from subsurface microstructure adds up
coherently, resulting in speckle. Polarization offers a complementary endogenous contrast mechanism that can
afford contrast between tissues that are indiscernible in OCT’s backscattering signal. Many tissues with a
fibrillar architecture exhibit birefringence and delay light depending on the alignment of its polarization state
with the fibrillar tissue components.
Specific Aim 1 capitalizes on tissue’s intrinsic birefringence to measure the orientation of fibrillar tissue
elements in all three spatial dimensions through fiber-optic imaging probes. This is specifically relevant for
imaging birefringent white matter tracts during stereotactic neurosurgery in the brain. Imaging probes
containing two imaging channels at distinct illumination angles and interfaced through a multi-channel motor
drive unit will be fabricated. Algorithms that leverage the multiple imaging angles and observe additional
continuity constraints will be developed to reconstruct 3D vectorial birefringence. Visualizing the 3D orientation
of axonal tracts surrounding an intracranial probe will enable microscopic guidance of stereotactic procedures,
such as the implantation of stimulation electrodes for deep brain stimulation.
Specific Aim 2 responds to the persistent challenge of speckle in OCT by leveraging machine learning to
encapsulate the physical meaning of hardware-based speckle suppression into a trained algorithm. A novel
method to generate ground truth speckle-suppressed tomograms using sample tilting for angular compounding
will be developed to enable supervised training of a deep neural network. The specific challenge of deploying
the trained algorithm to new imaging systems will be addressed by developing both a supervised and an
unsupervised method for domain adaptation. Improved image contrast and speckle suppression are critical for
interpretation of many tissue pathologies, including, e.g., the diagnosis and staging of skin and oral cancer.
Combined, these efforts will improve the contrast achievable with probe-based OCT, thereby enhancing its
practical use and extend...

## Key facts

- **NIH application ID:** 10494623
- **Project number:** 2P41EB015903-11A1
- **Recipient organization:** MASSACHUSETTS GENERAL HOSPITAL
- **Principal Investigator:** Martin Villiger
- **Activity code:** P41 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $319,160
- **Award type:** 2
- **Project period:** 2011-07-21 → 2027-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10494623

## Citation

> US National Institutes of Health, RePORTER application 10494623, TRD3: Endoscopic and Probe-based Coherence Imaging (2P41EB015903-11A1). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10494623. Licensed CC0.

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