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Proceedings Paper

Visible light optical coherence tomography for microvascular oximetry in ocular circulation (Conference Presentation)
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Paper 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.

Paper Details

Date Published: 26 April 2016
PDF: 1 pages
Proc. SPIE 9697, Optical Coherence Tomography and Coherence Domain Optical Methods in Biomedicine XX, 96970H (26 April 2016); doi: 10.1117/12.2214755
Show Author Affiliations
Siyu Chen, Northwestern Univ. (United States)
Ji Yi, Northwestern Univ. (United States)
Hao F. Zhang, Northwestern Univ. (United States)


Published in SPIE Proceedings Vol. 9697:
Optical Coherence Tomography and Coherence Domain Optical Methods in Biomedicine XX
Joseph A. Izatt; James G. Fujimoto; Valery V. Tuchin, Editor(s)

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