Measurements of slow tissue dynamics with short-separation speckle contrast optical spectroscopy.

Autor:	Liu B; Neurophotonics Center, Boston University, Boston, Massachusetts 02215, USA.; Department of Electrical and Computer Engineering, Boston University, Boston, Massachusetts 02215, USA., Shah S; Neurophotonics Center, Boston University, Boston, Massachusetts 02215, USA.; Department of Biomedical Engineering, Boston University, Boston, Massachusetts 02215, USA., Küreli G; Neurophotonics Center, Boston University, Boston, Massachusetts 02215, USA., Devor A; Neurophotonics Center, Boston University, Boston, Massachusetts 02215, USA.; Department of Biomedical Engineering, Boston University, Boston, Massachusetts 02215, USA., Boas DA; Neurophotonics Center, Boston University, Boston, Massachusetts 02215, USA.; Department of Biomedical Engineering, Boston University, Boston, Massachusetts 02215, USA., Cheng X; Neurophotonics Center, Boston University, Boston, Massachusetts 02215, USA.; Department of Biomedical Engineering, Boston University, Boston, Massachusetts 02215, USA.
Jazyk:	angličtina
Zdroj:	Biomedical optics express [Biomed Opt Express] 2023 Aug 21; Vol. 14 (9), pp. 4790-4799. Date of Electronic Publication: 2023 Aug 21 (Print Publication: 2023).
DOI:	10.1364/BOE.497604
Abstrakt:	Laser speckle contrast imaging (LSCI) measures 2D maps of cerebral blood flow (CBF) in small animal brains such as mice. The contrast measured in LSCI also includes the static and slow-varying components that contain information about brain tissue dynamics. But these components are less studied as compared to the fast dynamics of CBF. In traditional wide-field LSCI, the contrast measured in the tissue is largely contaminated by neighboring blood vessels, which reduces the sensitivity to these static and slow components. Our goal is to enhance the sensitivity of the contrast to static and slow tissue dynamics and test models to quantify the characteristics of these components. To achieve this, we have developed a short-separation speckle contrast optical spectroscopy (ss-SCOS) system by implementing point illumination and point detection using multi-mode fiber arrays to enhance the static and slow components in speckle contrast measurements as compared to traditional wide-field LSCI (WF-LSCI). We observed larger fractions of the static and slow components when measured in the tissue using ss-SCOS than in traditional LSCI for the same animal and region of interest. We have also established models to obtain the fractions of the static and slow components and quantify the decorrelation time constants of the intensity auto-correlation function for both fast blood flow and slower tissue dynamics. Using ss-SCOS, we demonstrate the variations of fast and slow brain dynamics in animals before and post-stroke, as well as within an hour post-euthanasia. This technique establishes the foundation to measure brain tissue dynamics other than CBF, such as intracellular motility. Competing Interests: The authors declare no conflicts of interest. (© 2023 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement.)
Databáze:	MEDLINE
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