Real-time diffuse correlation spectroscopy with on-chip correlators for measuring human cerebral blood flow and brain function

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Wang, Quan and Hua, Yuanyuan and Li, Chenxu and Yuan, Zhizheng and Wang, Jing and Erdogan, Ahmet and Chen, Hanging and Huang, Xunting and Wojtkiewicz, Maciej and Gorman, Alistair and Pan, Mingliang and Zhang, Yuanzhe and Wang, Yining and Finlayson, Neil and Bi, Renzhe and Henderson, Robert and Yuan, Zhen and Li, David (2026) Real-time diffuse correlation spectroscopy with on-chip correlators for measuring human cerebral blood flow and brain function. Journal of Innovative Optical Health Sciences. (https://doi.org/10.1142/S1793545826500203)

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Abstract

Diffuse correlation spectroscopy (DCS) is a non‑invasive optical technique that probes microvascular blood flow in deep tissues. Here, we present and validate a new on‑chip hardware correlator for high‑speed DCS measurements. The correlator is embedded in a custom‑built 512 × 512 single‑photon avalanche diode (SPAD) array named ATLAS, which computes intensity autocorrelation functions directly on‑chip at a sampling rate of 116 Hz – the fastest DCS acquisition reported to date. Unlike conventional DCS systems that suffer from low light throughput and therefore cannot resolve cardiac pulsations at source‑detector separations (ρ) beyond 30 mm, our massively parallel on‑chip architecture computes autocorrelations within each macropixel, eliminating the data‑throughput bottleneck. This enables high‑SNR, real‑time detection of pulsatile blood flow even at ρ = 50 mm on the human forehead. In phantom experiments at ρ = 25 mm, ATLAS‑DCS achieves a 12‑fold improvement in signal‑to‑noise ratio over a conventional single‑channel DCS instrument while operating at 116 Hz. In human subjects, we resolve functional hyperemia during a mental arithmetic task at ρ = 30 mm. Furthermore, we integrate ATLAS‑DCS with a frequency‑domain near‑infrared spectroscopy (FD‑NIRS) module, enabling simultaneous monitoring of blood flow and tissue oxygenation. With this combined system, we can concurrently resolve core hemodynamic parameters. The on‑chip parallelized DCS design substantially improves detection speed, depth sensitivity, and real‑time capability, paving the way for wearable, high‑speed cerebral blood flow monitoring in both clinical and research settings.

ORCID iDs

Wang, Quan, Hua, Yuanyuan, Li, Chenxu, Yuan, Zhizheng, Wang, Jing, Erdogan, Ahmet, Chen, Hanging, Huang, Xunting, Wojtkiewicz, Maciej, Gorman, Alistair, Pan, Mingliang ORCID logoORCID: https://orcid.org/0009-0001-9732-8963, Zhang, Yuanzhe ORCID logoORCID: https://orcid.org/0009-0004-5107-3856, Wang, Yining, Finlayson, Neil, Bi, Renzhe, Henderson, Robert, Yuan, Zhen and Li, David ORCID logoORCID: https://orcid.org/0000-0002-6401-4263;
CORE (COnnecting REpositories)