Beneath the surface: revealing deep-tissue blood flow in human subjects with massively parallelized diffuse correlation spectroscopy

• DOI: 10.1117/1.nph.12.2.025007
• Publication Date: 2025-04-09T21:56:26Z
• Authors: Lucas Kreiss; Melissa Wu; Michael Wayne; Shiqi Xu; Paul McKee; Derrick Dwamena; Kanghyun Kim; Kyung Chul Lee; Kyle R. Cowdrick; Wenhui Liu; Arin Ülkü; Mark Harfouche; Xi Yang; Clare Cook; Seung Ah Lee; Erin Buckley; Claudio Bruschini; Edoardo Charbon; Scott Huettel; Roarke Horstmeyer

Diffuse correlation spectroscopy (DCS) allows label-free, non-invasive investigation of microvascular dynamics deep within tissue, such as cerebral blood flow (CBF). However, the signal-to-noise ratio (SNR) in DCS limits its effective sensitivity adults, which depth to brain, through scalp and skull, is substantially larger than infants. Therefore, we aim increase SNR and, ultimately, CBF new techniques. We present an vivo demonstration parallelized (PDCS) measure muscular healthy adults. Our setup employs innovative array with hundreds thousands single photon avalanche diodes (SPAD) a 500×500 grid boost by averaging all independent pixel measurements. tested this device on different total counts frame rates. A secondary, smaller was used for reference measurements from shallower tissue at lower source-detector-separation (SDS). The system can pulsatile up 4 cm SDS, while maintaining similar measurement noise compared previously published 32×32 PDCS 1.5 SDS. Data cohort 15 adults provide strong experimental evidence functional activity during cognitive memory task allowed analysis pulse markers. Additional control experiments forearm technical configuration converging efficacy technique. results outline successful large SPAD arrays enable detect human ongoing development camera technology expected result faster detectors future. In combination data processing techniques, tailored sparse signal binary detection events SPADs, could lead even greater ultimately PDCS.