Multi-wavelength multi-distance approach for evaluating the metabolic activity of the brain in diffuse correlation spectroscopy and wearable near infrared spectroscopy
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Citation
Abstract
The adult human brain, despite comprising only 2% of our total mass, is responsible for roughly 20% of our total energy consumption. In healthy individuals, cerebral autoregulation maintains consistent blood flow to meet the brain’s high metabolic demands, even during systemic fluctuations. However, in vulnerable populations such as neonates—particularly those at risk of brain injury—this regulatory mechanism may be impaired, underscoring the need for non-invasive, continuous monitoring of cerebral oxygenation and metabolism. Optical imaging modalities such as near-infrared spectroscopy (NIRS) and diffuse correlation spectroscopy (DCS) are emerging non-invasive tools capable of continuous monitoring of cerebral parameters such as oxygenation and blood flow. In this thesis, I present the development and validation of two novel, multi-wavelength (MW) optical systems for monitoring cerebral metabolism in neonates. The first is a MW multi-distance DCS system, designed to estimate the cerebral metabolic rate of oxygen (CMRO₂) by combining blood flow and oxygenation measurements. The second is the MW FlexNIRS, a wearable, wireless NIRS device capable of resolving changes in mitochondrial metabolism by tracking concentration changes in oxidized cytochrome c oxidase in addition to oxy- and deoxyhemoglobin. To complement this device a wavelength-weighted algorithm was developed to account for the broad LED emission profiles and photodiode responsivity. We performed extensive validation for both devices and show preliminary clinical data obtained on infants. These systems represent key steps toward accessible, non-invasive, real-time monitoring of cerebral metabolic health in the neonatal intensive care setting.
Description
2025
License
Attribution 4.0 International