Presentation
26 April 2016 Visible light optical coherence tomography for microvascular oximetry in ocular circulation (Conference Presentation)
Author Affiliations +
Abstract
Visible light optical coherence tomography (vis-OCT) is intrinsically capable of optical determination of blood oxygen saturation (sO2). Thanks to its 3D sectioning ability, confounding factors that plaque multi-wavelength fundus photography can be avoided. We further supplemented it with motion-enhanced angiography (vis-OCTA), which allowed us to resolve retinal micro vessels without losing spectral information. As a result, spectroscopic vis-OCTA can extract microvascular sO2 which are generally inaccessible. Here we extend the theoretical formulation of vis-OCTA oximetry to include optical attenuation, scattering and motion contrast. The model allows robust estimation of sO2, while also promising reduction of illuminating power to 1/3 of current value of ~1 mW. To demonstrate the capability of our approach, we performed oxygen challenge while taking vis-OCTA measurements on rat ocular circulation in vivo. We supplied the experiment animal with the following gas mixture: normal air, 5% CO2 air, pure O2 and 10% O2 air. For each inhalation gas, the OCTA measurements were compared with peripheral capillary sO2 (spO2) provided by a pulse oximeter. The retinal artery sO2 measurements corresponded well with spO2 reading as expected (R2 = 0.87). We found that both retinal and choroidal circulation sO2 moderately increased when we supplied 5% CO2 air. 100% O2 inhalation significantly increased both artery and vein oxygenation. On the contrary, 10% O2 air could deplete the oxygen reservoir in the circulation and lead to low sO2 readings.
Conference Presentation
© (2016) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Siyu Chen, Ji Yi, and Hao F. Zhang "Visible light optical coherence tomography for microvascular oximetry in ocular circulation (Conference Presentation)", Proc. SPIE 9697, Optical Coherence Tomography and Coherence Domain Optical Methods in Biomedicine XX, 96970H (26 April 2016); https://doi.org/10.1117/12.2214755
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KEYWORDS
Oxygen

Optical coherence tomography

Oximetry

Visible radiation

Arteries

Carbon dioxide

Angiography

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