Purchase this article with an account.
Farzan Abdolahi, Xiao Zhou, Bright Senyo Ashimatey, Zhongdi Chu, Ruikang K Wang, Amir H Kashani; Assessment of Physiological Changes in Retinal Capillary Blood Flow in the Healthy Human Retina Using OCTA. Invest. Ophthalmol. Vis. Sci. 2021;62(8):1759.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To compare optical coherence tomography angiography (OCTA) derived flux with conventional OCTA measures of retinal vascular density
3 x 3 mm2 fovea-centered images were acquired from healthy human subjects using a commercially available swept-source OCTA (SS-OCTA). Imaging was performed while subjects were breathing either room air (RA), 100% O2, or 5% CO2. Retinal perfusion was quantified in each condition using previously described measures of vessel area density (VAD) and vessel skeleton density (VSD) derived from binarized OCTA images. Vessel area flux (VAF) and vessel skeleton flux (VSF) are two novel measures of retinal perfusion based on non-binarized intensities from raw OCTA images. Flux approximates the number of red blood cells moving through a vessel segment per unit time and more accurately reflects small changes in blood flow. Retinal vascular reactivity (RVR) is reported as the percentage change in each OCTA measure between gas conditions (O2-RA and CO2-RA). Analyses were performed for all-vessel (including arterioles and venules) as well as capillary-only OCTA images. Statistical significance was determined using paired t-tests and a linear mixed effects model with a p-value of < 0.05.
84 OCTA images (one image per gas condition) from 29 subjects were included (mean age 45.9 ± 19.5 years; 48.3% male). Flux measures, VAF and VSF, showed significantly greater relative magnitude of change compared to density measures, VAD and VSD, in all gas conditions. In CO2 condition, the change was 168% greater in VAF than VAD (p = 0.002), and 124% greater in VSF than VSD (p = 0.004). Similarly, in O2 condition, the change was 43% greater in VAF than VAD (p = 0.003), and 57% greater in VSF than VSD (p 0.01), Fig 1. Flux measures also had a significantly greater magnitude of change in capillary-only images compared to all-vessel images. The change in VAF in capillary-only images was 20% greater in CO2 (p = 0.01), and 25% greater in O2 (p = 0.001) condition compared to all-vessel images. VSF showed a similarly significant trend.
OCTA-derived flux measures quantify autoregulatory changes in retinal blood flow at the capillary level with a greater effect size than conventional vessel density measures.
This is a 2021 ARVO Annual Meeting abstract.
Fig 1. Comparison of the change in OCTA derived flux (VAF, VSF) versus density (VAD, VSD) measures in capillary-only images. (Mean and 95% CI of mean are shown)
This PDF is available to Subscribers Only