Mapping human cerebral blood flow with high-density, multi-channel speckle contrast optical spectroscopy

Cerebral blood flow (CBF) dysregulation is correlated with pathologies including ischemic stroke and Alzheimer’s disease. Portable real-time CBF monitoring, with spatial specificity, would aid neuroscience research and clinical decision-making. Recently, speckle contrast optical spectroscopy (SCOS) enabled non-invasive human CBF measurement, demonstrating a higher signal-to-noise ratio (SNR) compared to traditional optical methods. This work advances the SCOS state-of-the-art by developing a high-density, multi-channel SCOS system to map CBF during human brain activation. A laser multiplexed to 7 source fibers transmits light through multiple head locations to 17 cameras. Speckle images were analyzed to obtain optical density changes (ΔOD) based on tissue absorption, and relative CBF changes from laser speckle statistics. We validated the system’s spatial specificity using a liquid phantom setup and demonstrated its application in measuring human brain activation maps, showing CBF and OD changes in the prefrontal cortex during a cognitive task. This work provides a tool for spatiotemporal monitoring of CBF for both neuroscience and brain health applications.