Study of the pressure effect in near-infrared spectroscopy

It has been observed for a long time that the compressive pressure applied on the tissue significantly effects the measurement of Near-Infrared Spectroscopy. The clinical study implies a certain level of correlation between the tissue type and its response to pressure. However, this correlation is not quite understood nor quantified yet, especially in the diffuse optical imaging arena. This paper discusses the development of NIRS tissue spectrometer with real time pressure monitoring and a series of pressure regulated experiments we have conducted on human subjects. By analyzing the pattern of the 2D mapping of tissue hemoglobin concentration and oxygen saturation in response to the temporal profile of the compression force, we are able to explore major factors that influence the pressure regulated measurement.