Light-scattering–assisted near-infrared spectroscopy for improved quantitative analysis of tissue chromophores and oxygenation

Near-infrared spectroscopy (NIRS) is a noninvasive and quantitative technique for analyzing biological tissues, particularly effective within the 670–1,000 nm spectral range due to the high optical transparency of this window. NIRS enables real-time assessment of key chromophores—deoxyhemoglobin (Hb), oxyhemoglobin (HbO₂), and oxidized cytochrome c oxidase (CCO)—thereby providing valuable insights into tissue oxygenation and metabolic activity in vivo . However, conventional NIRS approaches often overlook the influence of tissue light scattering, leading to inaccuracies in chromophore quantification. To address this limitation, we developed a portable, four-wavelength enhanced NIRS system capable of simultaneously monitoring fluctuations in Hb, HbO₂, and CCO concentrations while capturing dynamic variations in tissue light-scattering properties. Experiments performed under diverse respiratory and circulatory conditions demonstrate that integrating light-scattering analysis substantially improves the accuracy of chromophore quantification. Our findings reveal that incorporating scattering information refines absorption evaluation and significantly enhances the precision of NIRS-based oxygenation monitoring. This light-scattering–assisted approach advances the analytical performance of NIRS and extends its applicability for comprehensive physiological assessment in vivo , bridging the gap between scattering effects and quantitative tissue spectroscopy.