Pathlength-Selective, Interferometric Diffuse Correlation Spectroscopy

作者：Mitchell B. Robinson, Marco Renna, Nikola Otic, Olivia S. Kierul, Ailis Muldoon, Maria Angela Franceschini, Stefan A. Carp · 发表于：IEEE Journal of Selected Topics in Quantum Electronics · 年份：2025 · DOI：10.1109/jstqe.2025.3575719 · 被引用次数：5 · 研究领域：Optical Imaging and Spectroscopy Techniques、Spectroscopy Techniques in Biomedical and Chemical Research、Photoacoustic and Ultrasonic Imaging

In this work, we present an enhanced diffuse correlation spectroscopy (DCS) method called pathlength-selective, interferometric DCS (PaLS-iDCS), which uses pathlength-specific coherent gain to improve both the sensitivity to deep tissue hemodynamics and measurement SNR. Through interferometric detection, PaLS-iDCS can provide time-of-flight (ToF) specific blood flow information without the use of expensive time-tagging electronics and low-jitter detectors. The technique is compared to time-domain DCS (TD-DCS), another enhanced DCS method able to resolve photon ToF in tissue, through Monte Carlo simulation, phantom experiments, and human subject measurements. PaLS-iDCS consistently demonstrates improvements in SNR (>2x) for similar measurement conditions (same photon ToF), and the SNR improvements allow for measurements at extended photon ToFs, which have increased sensitivity to deep tissue hemodynamics (~50% increase). Further, like TD-DCS, PaLS-iDCS allows direct estimation of tissue optical properties from the sampled ToF distribution. This method offers a relatively straightforward way to allow DCS systems to make robust measurements of blood flow with greatly enhanced sensitivity to deep tissue hemodynamics without the need for time-resolved detection, enabling further applications of this non-invasive technology.