A low cost portable high speed quantitative system for diffuse optical spectroscopic imaging of human tissue. The hybrid system (CWFD) can measure absolute optical properties from 660 nm to 980 nm and recover all tissue chromophore concentrations. The standalone FD module can be utilized to measure scattering at every measurement and recover deoxygenated and oxygenated hemoglobin concentrations. The CW module can operate concurrently with the FD module to also measure water and lipid. The high temporal resolution and large signal-to-noise ratio of the CWFD system may be used to explore tissue oximetry, vascular occlusion, and paced breathing models to measure and analyze tissue hemodynamics response to changes in blood flow. Continuous monitoring of vasculature response to various modified blood perfusion conditions can provide information about local tissue metabolism and physiological state (dysfunction).