Beneath the Surface: Revealing Deep-Tissue Blood Flow in Human Subjects with Massively Parallelized Diffuse Correlation Spectroscopy

• DOI: 10.48550/arxiv.2403.03968
• Publication Date: 2024-03-06
• Authors: Lucas Kreiß; Melissa M. Wu; Michael A. Wayne; Shiqi Xu; Paul McKee; Derrick Dwamena; Kanghyun Kim; Kyung Chul Lee; Wenhui Liu; Aarin Ulku; Mark Harfouche; Xi Yang; Clare Cook; Amey Chaware; Seung Ah Lee; Erin M. Buckley; Claudio Bruschini; Edoardo Charbon; Scott A. Huettel; Roarke Horstmeyer
• Keywords: FOS: Physical sciences; Medical Physics (physics.med-ph); Physics - Medical Physics; Physics - Optics; Optics (physics.optics)

Diffuse Correlation Spectroscopy (DCS) allows the label-free investigation of microvascular dynamics deep within living tissue. However, common implementations DCS are currently limited to measurement depths $\sim 1-1.5cm$, which can limit accuracy cerebral hemodynamics measurement. Here we present massively parallelized (pDCS) using novel single photon avalanche detector (SPAD) arrays with up 500x500 individual channels. The new SPAD array technology boost signal-to-noise ratio by a factor 500 compared single-pixel DCS, or more than 15-fold most recent state-of-the-art pDCS demonstrations. Our results demonstrate first in vivo use this system measure blood flow changes at 2cm$ depth human adults. We different modes operation and applied dual detection strategy, where secondary is used simultaneously assess superficial as built-in reference While scalp tissue showed no significant change during cognitive activation, statistically increase derived index 8-12% when control rest state.