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Proceedings Paper

Quantifying low-frequency fluctuations in the laser Doppler flow signal from human skin
Author(s): M. S. Folgosi-Correa; G. E. C. Nogueira
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Paper Abstract

Low-frequency fluctuations in the laser Doppler flow signal (LDFS) from the skin are related to microvascular mechanisms of flow control. Wavelet spectral analysis has been used to correlate fluctuations in the LDFS with the endothelial, neurogenic and myogenic mechanisms of control in the frequency intervals 0.005-0.02 Hz, 0.02-0.06 Hz and 0.06-0.16 Hz, respectively. Generally the signal power, in each frequency interval, derived from the respective wavelet coefficients, is used as a measure of the activity of the related mechanism of microvascular control. However, the time-domain characteristics of the fluctuations in the LDFS in each frequency interval are poorly known. As a consequence, there is a lack of objective criteria to properly measure, in each frequency interval, the related hemodynamic parameters. Here a time-domain method is proposed to analyze and quantify fluctuations in the LDFS in each frequency band. Baseline (32 degrees Celsius) and thermally stimulated (42 degrees Celsius) LDFS of forearms from 15 healthy volunteers were collected and analyzed. The data obtained indicate that inappropriate time windows, frequently used for measurements, increase the variability of the measured signal power, diminishing the capability of the method when assessing microvascular dynamics and dysfunctions. To overcome this limitation, an objective method to measure the LDFS power in each frequency band is proposed.

Paper Details

Date Published: 10 February 2011
PDF: 6 pages
Proc. SPIE 7898, Dynamics and Fluctuations in Biomedical Photonics VIII, 789811 (10 February 2011); doi: 10.1117/12.874080
Show Author Affiliations
M. S. Folgosi-Correa, Instituto de Pesquisas Energéticas e Nucleares (Brazil)
G. E. C. Nogueira, Instituto de Pesquisas Energéticas e Nucleares (Brazil)


Published in SPIE Proceedings Vol. 7898:
Dynamics and Fluctuations in Biomedical Photonics VIII
Valery V. Tuchin; Donald D. Duncan; Kirill V. Larin; Martin J. Leahy; Ruikang K. Wang, Editor(s)

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