title: Characterizing relationship between optical microangiography signals and capillary flow using microfluidic channels.
abstract: Optical microangiography (OMAG) is a powerful optical angio-graphic tool to visualize micro-vascular flow in vivo. Despite numerous demonstrations for the past several years of the qualitative relationship between OMAG and flow, no convincing quantitative relationship has been proven. In this paper, we attempt to quantitatively correlate the OMAG signal with flow. Specifically, we develop a simplified analytical model of the complex OMAG, suggesting that the OMAG signal is a product of the number of particles in an imaging voxel and the decorrelation of OCT (optical coherence tomography) signal, determined by flow velocity, inter-frame time interval, and wavelength of the light source. Numerical simulation with the proposed model reveals that if the OCT amplitudes are correlated, the OMAG signal is related to a total number of particles across the imaging voxel cross-section per unit time (flux); otherwise it would be saturated but its strength is proportional to the number of particles in the imaging voxel (concentration). The relationship is validated using microfluidic flow phantoms with various preset flow metrics. This work suggests OMAG is a promising quantitative tool for the assessment of vascular flow.
authors.affiliation: Department of Bioengineering, University of Washington, 3720 15th NE, Seattle, WA 98195, USA; These authors contributed equally to this work.
authors.forename: Woo June
authors.initials: WJ
authors.lastname: Choi
authors.affiliation: Department of Bioengineering, University of Washington, 3720 15th NE, Seattle, WA 98195, USA; These authors contributed equally to this work.
authors.forename: Wan
authors.initials: W
authors.lastname: Qin
authors.affiliation: Department of Bioengineering, University of Washington, 3720 15th NE, Seattle, WA 98195, USA.
authors.forename: Chieh-Li
authors.initials: CL
authors.lastname: Chen
authors.affiliation: Department of Bioengineering, University of Washington, 3720 15th NE, Seattle, WA 98195, USA.
authors.forename: Jingang
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Bioengineering, University of Washington, 3720 15th NE, Seattle, WA 98195, USA.
authors.forename: Qinqin
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Department of Bioengineering and COMSET, Clemson University, Clemson, SC 29634, USA.
authors.forename: Xiaoqi
authors.initials: X
authors.lastname: Yang
authors.affiliation: Department of Bioengineering and COMSET, Clemson University, Clemson, SC 29634, USA.
authors.forename: Bruce Z
authors.initials: BZ
authors.lastname: Gao
authors.affiliation: Department of Bioengineering, University of Washington, 3720 15th NE, Seattle, WA 98195, USA.
authors.forename: Ruikang K
authors.initials: RK
authors.lastname: Wang
keywords: (170.2655) Functional monitoring and imaging; (170.4500) Optical coherence tomography; (220.4000) Microstructure fabrication