Interrelation of temperature and blood flow oscillations of fingers

Interrelation of the skin temperature and the blood flow oscillations of the finger phalanxes at normal environment in healthy subjects has been investigated. Oscillations of the blood flow measured by means of the photoplethysmography, the temperature measurements performed by means of thermal infrared camera.
The method of blood flow reconstruction by temperature oscillations with use of the Pennes bioheat transfer equation and a definition of a delay time of the temperature in relation to the blood flow signal has been described. The temperature oscillations have a lag in relation to the blood flow oscillations approximately of 10-20 seconds as a result of a finite transfer time of the temperature waves, propagating from the blood vessels to the skin surface. Delay time and diffusion rate of the temperature waves can be used for the definition of an effective thickness of a tissue layer parting the blood vessels and the skin surface.
Using of the described technique of comparison of the finger blood flow and the temperature oscillations allows to raise correlation coefficient of the signals in average from 0.35 to 0.63, that testifies of high degree conditionality of the temperature oscillations by the blood flow oscillations. Rising of a correlation coefficient of the temperature and the blood flow should simplify the analysis of the signals in time-frequency domain.
The considered method of non-contact restoration of blood flow oscillations by means of temperature oscillation measurements might find practical application in researches of skin thermal lesions, researches of influence of physical, chemical factors on a haemodynamics of peripheric vessels and skin microcirculation.

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