Measurement of Cerebral Blood Flow in Adult Humans Using Near Infrared Spectroscopy — Methodology and Possible Errors

Elwell, Clare E.; Cope, M; Edwards, Anthony; Wyatt, John; Reynolds, E. O. R.; Delpy, David T.

doi:10.1007/978-1-4615-3428-0_25

Cited by 83 publications

(38 citation statements)

References 16 publications

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“…Calculations of Hb and HbO 2 concentration changes have been performed by the well established ''modified Beer-Lambert law'' [12,27,31,35]. There has been some controversy in the literature on whether neuronal activation should be monitored with Hb, HbO 2 , Oxygenation (HbO 2 -Hb), or total Hb (THb = HbO 2 + Hb) [1,7,10,11,15,24,27,28,[32][33][34]36]. While most of these studies stress that HbO 2 reflects neuronal activation more reliably and consistently, some others have shown that this effect is only global.…”

Section: Measurementsmentioning

confidence: 99%

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Extraction of cognitive activity-related waveforms from functional near-infrared spectroscopy signals

2006

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We address the problem of prototypical waveform extraction in cognitive experiments using functional near-infrared spectroscopy (fNIRS) signals. These waveform responses are evoked with visual stimuli provided in an oddball type experimental protocol. As the statistical signal-processing tool, we consider the linear signal space representation paradigm and use independent component analysis (ICA). The assumptions underlying ICA is discussed in the light of the signal measurement and generation mechanisms in the brain. The ICA-based waveform extraction is validated based both on its conformance to the parametric brain hemodynamic response (BHR) model and to the coherent averaging technique. We assess the intra-subject and inter-subject waveform and parameter variability.

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Section: Measurementsmentioning

confidence: 99%

“…Delpy et al [11,12] have addressed the issues of tissue characterization, optical path length determination and monitoring of cerebral blood flow mechanisms. Villringer et al [27-29, 31, 35] reported their studies on the brain's response to visual and motor stimuli.…”

Section: Introductionmentioning

confidence: 99%

Extraction of cognitive activity-related waveforms from functional near-infrared spectroscopy signals

2006

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“…Measurement of global CBF depends on the induction of a rapid increase in arterial oxygen saturation, induced by a rapid change in the inspired oxygen concentration. The small additional bolus of HbO # acts as an intravascular tracer and using the Fick principle, CBF is obtained from the immediate rise in cerebral [HbO # ] (Edwards et al 1988 ;Elwell et al 1992).…”

Section: Nirs Studies In Newborn Infantsmentioning

confidence: 99%

“…The measurement of CBF involves additional assumptions, which have been discussed elsewhere (Elwell et al 1992). It is assumed that the small additional bolus of intravascular oxyhaemoglobin acts as a biologically inert tracer molecule and that there is no alteration in CBF, CBV or cerebral oxygen extraction during the experiment.…”

Section: Nirs Studies In Newborn Infantsmentioning

confidence: 99%

Cerebral oxygenation and haemodynamics in the foetus and newborn infant

Wyatt

1997

Phil. Trans. R. Soc. Lond. B

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SUMMARYuantitative techniques have been derived for the measurement of global cerebral blood flow, cerebral blood volume, its response to changing arterial carbon dioxide tension and mixed cerebral venous saturation in the human newborn undergoing intensive care. Normal ranges have been established and significant disturbances of cerebral oxygenation and perfusion have been demonstrated in a variety of pathological conditions. Recently, absolute cerebral deoxyhaemoglobin concentration has been obtained in the newborn using second differential spectroscopy. When combined with the measurement of total cerebral haemoglobin concentration, the mean saturation of cerebral blood (SmcO # ) may be obtained, allowing global cerebral oxygenation to be determined continuously in the intensive care unit.Marked changes in the concentrations of cerebral oxy-and deoxyhaemoglobin have been observed in foetuses undergoing labour. Measurements of SmcO # from the foetal brain prior to delivery have shown the expected close correlation with acid-base status at birth. Although movement artefact remains a theoretical risk during uterine contractions, preliminary measurements of optical path length by intensitymodulated spectroscopy have demonstrated only small fluctuations. In future the clinical application of time, phase and spatially resolved spectroscopy is likely to improve both the quantitative accuracy and the regional specificity of physiological measurements in the foetal and neonatal brain.

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“…Near-infra-red spectroscopy (NIRS) has previously been used to monitor changes in cerebral oxygenation and haemodynamics in neonates and adults [1,2]. NIRS systems to date have predominantly displayed parameters, such as changes in oxygenated and deoxygenated haemoglobin concentrations, which are unfamiliar to clinicians.…”

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confidence: 99%

A comparison of cerebral oxygenation as measured by the NIRO 300 and the INVOS 5100 Near‐Infrared Spectrophotometers

Broadhead²,

et al. 2002

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SummaryIn this study cerebral oxygenation was measured using the NIRO 300 and the INVOS 5100 spectrophotometers in 10 healthy adult volunteers, exposed to varying degrees of hyperoxia and hypoxia. The results showed similar baseline values for tissue oxygenation index and regional cerebral oxygen saturation with mean (SD) values being 64.9% (5.1) and 62.3% (6.0), respectively. The overall bias was -2.1%, with the INVOS 5100 under-reading cerebral oxygenation compared to the NIRO 300, with limits of agreement of ±14.7%. Both monitors demonstrated similar changes in response to hyperoxia and hypocapnia (coefficient of variance for F I O 2 0.45 ¼ 10.0%, F I O 2 1.0 ¼ 10.1%, hypocapnia ¼ 14.5%). The reasons for the bias and variability may relate to differences in the methodological approaches of the two monitors. The correlation between the monitors in response to changes in cerebral oxygenation implies that they may be useful as trend monitors in clinical practice.

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Measurement of Cerebral Blood Flow in Adult Humans Using Near Infrared Spectroscopy — Methodology and Possible Errors

Cited by 83 publications

References 16 publications

Extraction of cognitive activity-related waveforms from functional near-infrared spectroscopy signals

Extraction of cognitive activity-related waveforms from functional near-infrared spectroscopy signals

Cerebral oxygenation and haemodynamics in the foetus and newborn infant

A comparison of cerebral oxygenation as measured by the NIRO 300 and the INVOS 5100 Near‐Infrared Spectrophotometers

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