Measuring human cerebral blood flow and brain function with fiber-based speckle contrast optical spectroscopy system

Area of Science:

• Neuroimaging
• Biomedical Optics
• Cerebrovascular Physiology

Background:

• Cerebral blood flow (CBF) is vital for brain health and function.
• Accurate measurement of CBF is essential for understanding brain activity and neurological conditions.
• Current optical techniques for CBF measurement have limitations in sensitivity and depth penetration.

Purpose of the Study:

• To demonstrate the capability of fiber-based Speckle Contrast Optical Spectroscopy (SCOS) for measuring human brain activation.
• To evaluate SCOS performance at large source-detector separations (33 mm) for enhanced cerebral sensitivity.
• To compare SCOS with Diffuse Correlation Spectroscopy (DCS) for CBF monitoring.

Main Methods:

• Development of a fiber-based SCOS system utilizing CMOS detectors.
• Implementation of a pulsing strategy to increase photon flux for improved signal quality.
• Application of a sophisticated data processing pipeline to enhance measurement accuracy.
• Measurement of CBF changes during human brain activation tasks.

Main Results:

• The fiber-based SCOS system successfully measured human brain activation-induced CBF changes at 33 mm separations.
• SCOS demonstrated over 10x improvement in signal-to-noise ratio (SNR) compared to DCS.
• The system achieved comparable or greater sensitivity to cerebral blood flow over extracerebral flow.

Conclusions:

• Fiber-based SCOS is a viable and effective technique for functional neuroimaging of human brain activity.
• SCOS offers a cost-effective alternative to DCS with significantly improved SNR.
• This technology holds promise for cognitive neuroscience and clinical health science applications.