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07:13
Cerebral Blood Flow-Based Resting State Functional Connectivity of the Human Brain using Optical Diffuse Correlation Spectroscopy
Published on: May 27, 2020
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Highly parallel, interferometric diffusing wave spectroscopy for monitoring cerebral blood flow dynamics
Wenjun Zhou1, Oybek Kholiqov1, Shau Poh Chong1
1Department of Biomedical Engineering, University of California Davis, Davis, California 95616, USA.
Optica
|November 13, 2018
Summary
We developed a new technique using multimode fiber interferometry to improve deep tissue blood flow measurements. This method enhances sensitivity and speed for diffuse optics applications.
Area of Science:
- Soft matter physics
- Biomedical optics
- Diffuse optics
Background:
- Light-scattering methods are crucial for probing dynamics in turbid media like biological tissues.
- Current methods are limited by detector sensitivity, hindering high-speed deep tissue blood flow measurements.
- Low photon count rates due to weak diffuse light and low fiber throughput are significant challenges.
Purpose of the Study:
- To introduce multimode fiber (MMF) interferometry to diffuse optics.
- To enhance the sensitivity and parallel measurement capabilities of diffuse optical instruments.
- To enable high-speed, deep tissue blood flow measurements.
Main Methods:
- Developed a novel CMOS-based, multimode interferometric diffusing wave spectroscopy (iDWS) system.
- Utilized MMF interferometry to transform a CMOS camera into a sensitive detector array.
- Developed a matrix formalism to predict coherence and speckle number in iDWS.
Main Results:
- The iDWS system measures approximately 20 speckles simultaneously near the shot noise limit.
- The system functions as multiple independent photon-counting channels, significantly increasing detection capacity.
- Demonstrated in vivo pulsatile blood flow measurements in the adult human brain at 2.5 cm separation.
Conclusions:
- MMF interferometry offers a promising solution for overcoming limitations in diffuse optics.
- The novel iDWS system enhances sensitivity and parallel measurement capabilities for weak light fluxes.
- This technology has the potential to improve performance and reduce costs for diffuse optical instruments, particularly for deep tissue imaging.
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