Understanding cerebral blood flow is critical for diagnosing and managing neurological conditions, including strokes and migraines. However, noninvasive measurement remains challenging due to the obstructive nature of the scalp and skull, which also have their own blood supply. Researchers from the California Institute of Technology, the University of Southern California, Rancho Research Institute, the University of Toledo, and the National Neuroscience Institute of Singapore have developed a system that employs optical spectroscopy to address this issue.
The device uses an optical imaging method to target varying depths, distinguishing blood flow to the scalp from that to the brain. The team demonstrated its efficacy by temporarily blocking blood flow to the scalp at the superficial temporal artery, successfully isolating cerebral blood dynamics. This marks the first application of speckle contrast optical spectroscopy configured to eliminate noise from scalp blood flow.
Max Huang, a graduate student researcher at the California Institute of Technology, stated, “We’ve established a safe, simple, and repeatable experimental framework that other researchers can use to validate their own noninvasive optical systems. Instead of relying solely on simulations, groups can now use superficial temporal artery occlusion to get real-world data on their device’s scalp versus brain sensitivity.”
The device, housed in a headband, features a light source and seven detectors positioned at varying distances from the artery. This arrangement allows the device to identify signals from different depths, enabling clear differentiation between scalp and brain blood flow.
Upon temporarily blocking the superficial temporal artery, researchers noted a significant reduction in signals from the scalp-related shallow channels, while deeper channel signals remained unchanged. This was achieved by gently pressing on the artery and measuring the resulting signals.
Simon Mahler, another author, highlighted the challenge of individual variability, noting, “Some individuals have thicker scalp or skull layers, while others have thinner ones. This variability makes it difficult to design a single device that can be easily used across a large cohort of participants and means that results can vary between individuals.”
The research team aims to further validate and enhance the device, including integrating a sensor for direct skin application. This development could potentially revolutionise noninvasive cerebral blood flow measurement, offering new insights into neurological disorders.
