# Wide-field and projection-resolved optical coherence tomography angiography in diabetic retinopathy

> **NIH NIH R01** · OREGON HEALTH & SCIENCE UNIVERSITY · 2020 · $424,803

## Abstract

PROJECT SUMMARY
Our group has demonstrated that optical coherence tomography angiography (OCTA) can address many of
the disadvantages of fluorescein angiography (FA) in diabetic retinopathy (DR). OCTA uses the intrinsic
contrast of blood cell motion and therefore does not require dye injection, making it entirely non-invasive and
suitable for routine examination. OCTA is three-dimensional and can detect retinal neovascularization by the
presence of flow in the normally avascular vitreous space, and can detect capillary dropout in the retinal and
choroidal circulations separately. The OCTA technology used by previous studies is limited by the small fields
of view (2.4-6 mm) and the projection artifacts in the deeper layers, which are caused by flowing blood cells in
the more superficial vessels. The current proposal will overcome the previous limitations by improving both the
hardware platform and software algorithms to obtain wide-field (WF) and projection-resolved (PR) OCTA.
1. Develop wide-field (WF) OCT system for imaging peripheral retinal circulation. We have developed a
200-kHz swept-source optical coherence tomography (SS-OCT) system. This system is ready for use in
clinical studies. We propose to further increase system speed and develop automatic registration and montage
algorithms to create ultrawide-field OCTA.
2. Improve the projection-resolved (PR) OCTA algorithm for imaging of retinal and choroidal plexuses.
We have preliminarily demonstrated that separation of three retinal plexuses improved the detection of early
vascular changes in DR. We will refine this algorithm and apply it to the WF-OCTA on the high-speed SS-OCT
systems.
3. Quantify neovascularization and nonperfusion areas using WF- and PR-OCTA in DR. We will further
optimize the automated quantification of all relevant DR endpoints, including nonperfusion of all vascular
layers, neovascularization, cyst volume, and retinal thickness maps on both commercial and custom OCT
systems proposed in this study.
4. Evaluate advanced OCTA for DR in clinical studies. The clinical studies with DR and control subjects are
as follows: (1) cross-sectional study to determine if WF- and PR-OCTA can detect nonperfusion and other
microvasculopathies with better sensitivity than conventional OCTA and if they can detect these changes even
in diabetics without photographic signs of DR; (2) long-term prospective observational study to determine if
quantitative WF- and PR-OCTA parameters can predict the risk of DR progression; and (3) short-term study in
patients undergoing treatment for diabetic macular edema or neovascularization to validate WF- and PR-OCTA
measurements of nonperfusion and neovascularization in comparison with ultrawide-field FA.

## Key facts

- **NIH application ID:** 9915916
- **Project number:** 5R01EY027833-04
- **Recipient organization:** OREGON HEALTH & SCIENCE UNIVERSITY
- **Principal Investigator:** Thomas Hwang
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $424,803
- **Award type:** 5
- **Project period:** 2017-05-01 → 2022-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9915916

## Citation

> US National Institutes of Health, RePORTER application 9915916, Wide-field and projection-resolved optical coherence tomography angiography in diabetic retinopathy (5R01EY027833-04). Retrieved via AI Analytics 2026-05-26 from https://api.ai-analytics.org/grant/nih/9915916. Licensed CC0.

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