Long-wavelength, interferometric diffuse correlation spectroscopy (LW-iDCS) for functional perfusion imaging

Optical functional brain imaging has typically been performed with functional near-infrared spectroscopy (fNIRS). While fNIRS measures hemoglobin concentration, diffuse correlation spectroscopy (DCS) can provide additional information through measurement of cerebral blood flow. Recent technological improvements in DCS, specifically interferometric detection, enhance signal-to-noise ratio (SNR) and enable parallelized measurements. We developed a multi-channel perfusion imaging system using long-wavelength interferometric DCS (LW-iDCS) at 1064 nm. This study compares cerebral blood flow responses measured by LW-iDCS with hemoglobin concentration changes measured by fNIRS during motor and cognitive tasks. Results highlight differences in hemodynamic responses, suggesting enhanced metabolic response insights from blood flow measurements.