Portable, high speed blood flow measurements enabled by long wavelength, interferometric diffuse correlation spectroscopy (LW-iDCS)

• Published in: Scientific reports Vol. 13; no. 1; pp. 8803 - 11
• Main Authors: Robinson, Mitchell B., Renna, Marco, Ozana, Nisan, Martin, Alyssa N., Otic, Nikola, Carp, Stefan A., Franceschini, Maria Angela
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 31.05.2023; Nature Publishing Group; Nature Portfolio
• Subjects: 631/443/1338/2729; 639/166/985; 639/624/1075/1083; 639/624/1107/527; Adult; Blood flow; Cerebral blood flow; Diagnostic Techniques, Cardiovascular; Hemodynamics; Humanities and Social Sciences; Humans; Interferometry; multidisciplinary; Nanotechnology; Science; Science (multidisciplinary); Signal-To-Noise Ratio; Spectroscopy; Spectrum analysis; Spectrum Analysis - methods; Wavelength
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-023-36074-8

Diffuse correlation spectroscopy (DCS) is an optical technique that can be used to characterize blood flow in tissue. The measurement of cerebral hemodynamics has arisen as a promising use case for DCS, though traditional implementations of DCS exhibit suboptimal signal-to-noise ratio (SNR) and cerebral sensitivity to make robust measurements of cerebral blood flow in adults. In this work, we present long wavelength, interferometric DCS (LW-iDCS), which combines the use of a longer illumination wavelength (1064 nm), multi-speckle, and interferometric detection, to improve both cerebral sensitivity and SNR. Through direct comparison with long wavelength DCS based on superconducting nanowire single photon detectors, we demonstrate an approximate 5× improvement in SNR over a single channel of LW-DCS in the measured blood flow signals in human subjects. We show equivalence of extracted blood flow between LW-DCS and LW-iDCS, and demonstrate the feasibility of LW-iDCS measured at 100 Hz at a source-detector separation of 3.5 cm. This improvement in performance has the potential to enable robust measurement of cerebral hemodynamics and unlock novel use cases for diffuse correlation spectroscopy.