Characterization of laser Doppler signal fluctuations in microvascular flow / Caracterização das flutuações do sinal laser doppller do fluxo  microvascular

AUTOR(ES)

Melissa Santos Folgosi Corrêa

FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

19/08/2011

RESUMO

The laser Doppler flow signal from the skin (LDFS) has low-frequency fluctuations which are related to microvascular mechanisms of flow control. The Fourier and the wavelet spectral analysis has been used to correlate fluctuations in the LDFS with the metabolic, metabolic NO-dependent, neurogenic and myogenic mechanisms of control in the frequency intervals 0.005-0.0095 Hz, 0.0095-0.02 Hz, 0.02-0.05 Hz and 0.05-0.15 Hz, respectively. The signal power, in each frequency interval, is generally used as a measure of the activity of the related mechanism of microvascular control. Since spectral analysis methods have been used, the time-domain characteristics of the fluctuations in the LDFS in each frequency interval are unknown. As a consequence, there is a lack of objective criteria to properly measure, in each frequency interval, the related hemodynamic parameters. The aim of this work was characterizing and quantifying temporal, spatial and spatial-temporal fluctuations in the LDFS in each frequency band, using a time-domain method. Baseline (320C) and thermally stimulated (420C) LDFS of volar forearms from 20 healthy volunteers were collected from two close regions and analyzed. The data obtained indicate that short-time windows (1 minute) are acceptable for quantifying the mean flow, and that larger time-windows are needed for quantifying the flow fluctuations. The spatialtemporal analysis revealed strong correlations between signals (all bands, except B5) from the two investigated regions, during large time intervals when thermally stimulated, and lower intragroup variability than the ones obtained for the mean values of fluctuations, suggesting that the time interval of correlation is a promising parameter for studying mechanisms of microvascular flow control.

ASSUNTO(S)

fluxo sanguineo cutâneo fluxometria laser doppler laser doppler flowmeter skin blood flow vasomotilidade vasomotion

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