Near-infrared diffuse optical spectroscopies for measurement of deep tissue blood flow, oxygenation and metabolism

Near-infrared (NIR) diffuse correlation spectroscopy (DCS) flowmeter is an emerging technique for measurement of deep tissue blood flow (up to centimeters). NIR spectroscopy (NIRS) can be used for quantification of tissue oxygenation. The combination of DCS tissue-flowmeter and NIRS tissue-oximeter allows for simultaneously quantifying tissue blood flow and oxygenation in deep tissues. A portable DCS flow-oximeter has also been developed for the measurement of relative changes of tissue blood flow and oxygenation. The novel DCS flow-oximeter employs a new design with significantly less cost (1/2), smaller size (1/5), simpler construction and easier operation compared to the hybrid instruments. Application examples in surgical rooms have shown that DCS-based techniques have high sensitivity to detect tissue hemodynamic changes in clinics. It is expected that with more clinical applications, DCS technologies will emerge rapidly as the technique of choice for clinical investigation of diseases and treatment responses.