Photoplethysmographic imaging of the low-frequency hemodynamics in peripheral vessels: comparison with infrared thermal imaging
Volkov I.U., Fomin A.V., Tsoi M.O., Skripal A.V. and Sagaidachnyi A.A.
Saratov State University, Saratov, Russia
Abstract
Photoplethysmographic imaging (iPPG) is one of the actively developing non-invasive methods of optical diagnostics of biological objects. This method is implemented by analyzing the intensity of visible or infrared radiation absorbed and reflected back from biological tissue. The dynamics of blood filling of the vessels leads to the modulation of radiation at each point of the biological tissue and the formation of a spatiotemporal intensity map. In most works, the possibilities of iPPG adopted for the analysis of hemodynamics in the cardiac range of about 1 Hz. In this paper the emphasis is on studying the possibilities of iPPG in the field of analysis of low-frequency hemodynamic processes in the range of less than 0.5 Hz.
Results: The spectral characteristics of the iPPG signal in the low-frequency range 0.005-0.5 Hz are summarized. Maps of blood flow oscillations in the endothelial, neurogenic, myogenic and respiratory ranges were presented. The obtained data were compared with the data of infrared thermographic imaging in the endothelial, neurogenic and myogenic ranges. Infrared thermography data confirm the adequacy of low-frequency PPG data on hemodynamics, which means the high potential in use of PPG method for analyzing low-frequency hemodynamic processes in biological tissues.
Speaker
Andrey Sagaidachnyi
Saratov State University
Russia
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