A Method and a Device Prototype for Noninvasive Measurements of Blood Perfusion in a Tissue

Noncoherent fluctuation spectroscopy (NFS) is described as an optical method for measuring the tissue blood perfusion. This method is based on the registration of low-frequency fluctuations of a backscattered signal from a tissue in the frequency range of 0-20 Hz. It allows the assessment of the blood-flow intensity in small blood vessels of the skin by calculating an integral parameter, the perfusion index, which is similar to that in the laser Doppler flowmetry (LDF) method. A device prototype in which LEDs at wavelengths of 568 and 808 nm are used in a miniature optical head was developed. The device makes it possible to perform diagnostics during the subject's motion via the use of LED light sources. It is shown that the NFS signal is comparable with the LDF signal. Thus, the NFS method can serve as an inexpensive alternative to the LDF method.