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Human cortical perfusion and the arterial pulse: a near-infrared spectroscopy study.

Kwan HC, Cheng A, Liu R, Borrett DS - BMC Physiol. (2004)

Bottom Line: The arterial pulse pattern was extracted from the left middle finger by means of plethesmographic techniques.Cross-correlation analysis was performed to provide evidence for a causal relation between the arterial pulse and relative changes in cortical total hemoglobin.In addition, the determination of the statistical significance of this relation was established by the use of phase-randomized surrogates.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Physiology Medical Sciences Building, Room 3232, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8 Canada. h.kwan@utoronto.ca

ABSTRACT

Background: The pulsatile nature of the arterial pulse induces a pulsatile perfusion pattern which can be observed in human cerebral cortex with non-invasive near-infrared spectroscopy. The present study attempts to establish a quantitative relation between these two events, even in situations of very weak signal-to-noise ratio in the cortical perfusion signal. The arterial pulse pattern was extracted from the left middle finger by means of plethesmographic techniques. Changes in cortical perfusion were detected with a continuous-wave reflectance spectrophotometer on the scalp overlying the left prefrontal cortex. Cross-correlation analysis was performed to provide evidence for a causal relation between the arterial pulse and relative changes in cortical total hemoglobin. In addition, the determination of the statistical significance of this relation was established by the use of phase-randomized surrogates.

Results: The results showed statistically significant cross correlation between the arterial and perfusion signals.

Conclusions: The approach designed in the present study can be utilized for a quantitative and continuous assessment of the perfusion states of the cerebral cortex in experimental and clinical settings even in situations of extremely low signal-to-noise ratio.

Show MeSH
Power spectrum of the arterial pulse computed from plethesmographic recording (lower trace of Figure 1) at the left middle finger. Power in arbitrary units.
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Figure 2: Power spectrum of the arterial pulse computed from plethesmographic recording (lower trace of Figure 1) at the left middle finger. Power in arbitrary units.

Mentions: During the period of recording, there was a sizable heart rate variability which contributed to a broad peak in the Fourier spectrum of the arterial pulse signal around 1.3 Hz, with a harmonic around 2.6 Hz (Figure 2). This variability might have contributed to this spectral smearing observed in the cortical signal (Figure 3).


Human cortical perfusion and the arterial pulse: a near-infrared spectroscopy study.

Kwan HC, Cheng A, Liu R, Borrett DS - BMC Physiol. (2004)

Power spectrum of the arterial pulse computed from plethesmographic recording (lower trace of Figure 1) at the left middle finger. Power in arbitrary units.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC411046&req=5

Figure 2: Power spectrum of the arterial pulse computed from plethesmographic recording (lower trace of Figure 1) at the left middle finger. Power in arbitrary units.
Mentions: During the period of recording, there was a sizable heart rate variability which contributed to a broad peak in the Fourier spectrum of the arterial pulse signal around 1.3 Hz, with a harmonic around 2.6 Hz (Figure 2). This variability might have contributed to this spectral smearing observed in the cortical signal (Figure 3).

Bottom Line: The arterial pulse pattern was extracted from the left middle finger by means of plethesmographic techniques.Cross-correlation analysis was performed to provide evidence for a causal relation between the arterial pulse and relative changes in cortical total hemoglobin.In addition, the determination of the statistical significance of this relation was established by the use of phase-randomized surrogates.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Physiology Medical Sciences Building, Room 3232, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8 Canada. h.kwan@utoronto.ca

ABSTRACT

Background: The pulsatile nature of the arterial pulse induces a pulsatile perfusion pattern which can be observed in human cerebral cortex with non-invasive near-infrared spectroscopy. The present study attempts to establish a quantitative relation between these two events, even in situations of very weak signal-to-noise ratio in the cortical perfusion signal. The arterial pulse pattern was extracted from the left middle finger by means of plethesmographic techniques. Changes in cortical perfusion were detected with a continuous-wave reflectance spectrophotometer on the scalp overlying the left prefrontal cortex. Cross-correlation analysis was performed to provide evidence for a causal relation between the arterial pulse and relative changes in cortical total hemoglobin. In addition, the determination of the statistical significance of this relation was established by the use of phase-randomized surrogates.

Results: The results showed statistically significant cross correlation between the arterial and perfusion signals.

Conclusions: The approach designed in the present study can be utilized for a quantitative and continuous assessment of the perfusion states of the cerebral cortex in experimental and clinical settings even in situations of extremely low signal-to-noise ratio.

Show MeSH