Functional Time Domain Diffuse Correlation Spectroscopy

• Published in: Frontiers in Neuroscience Vol. 16; p. 932119
• Main Authors: Ozana, Nisan, Lue, Niyom, Renna, Marco, Robinson, Mitchell B., Martin, Alyssa, Zavriyev, Alexander I., Carr, Bryce, Mazumder, Dibbyan, Blackwell, Megan H., Franceschini, Maria A., Carp, Stefan A.
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Media SA 01.08.2022; Frontiers Media S.A
• Subjects: cerebral blood flow; diffuse correlation spectroscopy (DCS); fNIRS (functional near infrared spectroscopy); neuroimaging (anatomic and functional); Neuroscience; Neurosciences. Biological psychiatry. Neuropsychiatry; optical neuroimaging; RC321-571; optical neuroimaging; cerebral blood flow; neuroimaging (anatomic and functional); fNIRS (functional near infrared spectroscopy); diffuse correlation spectroscopy (DCS)
• ISSN: 1662-453X; 1662-4548; 1662-453X
• DOI: 10.3389/fnins.2022.932119

Time-domain diffuse correlation spectroscopy (TD-DCS) offers a novel approach to high-spatial resolution functional brain imaging based on the direct quantification of cerebral blood flow (CBF) changes in response to neural activity. However, the signal-to-noise ratio (SNR) offered by previous TD-DCS instruments remains a challenge to achieving the high temporal resolution needed to resolve perfusion changes during functional measurements. Here we present a next-generation optimized functional TD-DCS system that combines a custom 1,064 nm pulse-shaped, quasi transform-limited, amplified laser source with a high-resolution time-tagging system and superconducting nanowire single-photon detectors (SNSPDs). System characterization and optimization was conducted on homogenous and two-layer intralipid phantoms before performing functional CBF measurements in six human subjects. By acquiring CBF signals at over 5 Hz for a late gate start time of the temporal point spread function (TPSF) at 15 mm source-detector separation, we demonstrate for the first time the measurement of blood flow responses to breath-holding and functional tasks using TD-DCS.