First-in-clinical application of a time-gated diffuse correlation spectroscopy system at 1064nm using superconducting nanowire single photon detectors

Abstract Recently proposed time-gated DCS (TG-DCS) has significant advantages compared to conventional CW-DCS, but it is still in an early stage and clinical capability has yet to be established. The main challenge for TG-DCS is the lower SNR when gating for the deeper travelling late photons. Longer wavelengths, such as 1064nm have a smaller effective attenuation coefficient and a higher power threshold in humans, which significantly increases the SNR. Here, we demonstrate the clinical utility of TG-DCS at 1064nm in a case study on a patient with severe traumatic brain injury admitted to the neuroscience intensive care unit (NSICU). We showed a significant correlation between TG-DCS early (ρ = 0.67) and late (ρ = 0.76) gated against invasive thermal diffusion flowmetry. We also analyzed TG-DCS at high temporal resolution (50 Hz) to elucidate pulsatile flow data. Overall, this study demonstrates the first clinical translation capability of the TG-DCS system at 1064nm using superconducting nanowire single photon detector.