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Journal of Biomedical Optics • Open Access

Laser speckle contrast imaging is sensitive to advective flux

Paper Abstract

Unlike laser Doppler flowmetry, there has yet to be presented a clear description of the physical variables that laser speckle contrast imaging (LSCI) is sensitive to. Herein, we present a theoretical basis for demonstrating that LSCI is sensitive to total flux and, in particular, the summation of diffusive flux and advective flux. We view LSCI from the perspective of mass transport and briefly derive the diffusion with drift equation in terms of an LSCI experiment. This equation reveals the relative sensitivity of LSCI to both diffusive flux and advective flux and, thereby, to both concentration and the ordered velocity of the scattering particles. We demonstrate this dependence through a short series of flow experiments that yield relationships between the calculated speckle contrast and the concentration of the scatterers (manifesting as changes in scattering coefficient), between speckle contrast and the velocity of the scattering fluid, and ultimately between speckle contrast and advective flux. Finally, we argue that the diffusion with drift equation can be used to support both Lorentzian and Gaussian correlation models that relate observed contrast to the movement of the scattering particles and that a weighted linear combination of these two models is likely the most appropriate model for relating speckle contrast to particle motion.

Paper Details

Date Published: 24 June 2016
PDF: 8 pages
J. Biomed. Opt. 21(7) 076001 doi: 10.1117/1.JBO.21.7.076001
Published in: Journal of Biomedical Optics Volume 21, Issue 7
Show Author Affiliations
Kosar Khaksari, Michigan Technological Univ. (United States)
Sean J. Kirkpatrick, Michigan Technological Univ. (United States)

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