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TitleMeasurement of dynamic scattering beneath stationary layers using multiple-exposure laser speckle contrast analysis
Publication TypeConference Paper
Year of Publication2013
AuthorsHirst, E., Thompson O., and Andrews M.K.
Conference NameProgress in Biomedical Optics and Imaging - Proceedings of SPIE
Date Published2013
KeywordsBlood flow, Blood vessels, Brownian movement, Contrast, Hemodynamics, Laser speckle, Multiple exposure, Photonics, Retina, Scattering, Speckle, Tissue
AbstractThe retina/choroid structure is an example of a complex biological target featuring highly perfused tissues and vessel flows both near the surface and at some depth. Laser speckle imaging can be used to image blood flows but static scattering paths present a problem for extracting quantifiable data. The speckle contrast is artificially increased by any residual specular reflection and light paths where no moving scatterers are encountered. Here we present results from phantom experiments demonstrating that the static and dynamic contributions to laser speckle contrast can be separated when camera exposures of varying duration are used. The stationary contrast parameter follows the thickness and strength of the overlying scatterer while the dynamic proportion of the scatter resulting from vessel flows and Brownian motion is unchanged. The importance of separating the two scatter components is illustrated by in vivo measurements from a scarred human retina, where the effect of the un-perfused scar tissue can be decoupled from the dynamic speckle from the intact tissue beneath it. © 2013 SPIE.

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