Oscillatory cerebral hemodynamics—the macro- vs. microvascular level

Reinhard, Matthias; Wehrle-Wieland, Elisabeth; Grabiak, Daniel; Roth, Markus; Guschlbauer, B.; Timmer, Jens; Weiller, Cornelius; Hetzel, Andreas

doi:10.1016/j.jns.2006.07.011

Cited by 121 publications

(181 citation statements)

References 27 publications

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“…On average, the amplitude of the HbR SSHO is only 11% smaller than that of HbO SSHO. In agreement with others (Reinhard et al, 2006; Watanabe et al, 2017), we found that the HbR SSHO were almost out‐of‐phase with the HbO SSHO,

Δ {normalϕ}_{Δ normalH normalb normalO - Δ normalH normalb normalR} \sim normalπ

. Therefore, the SSHO in total hemoglobin HbT (sum of HbO and HbR) is relatively small.…”

Section: Resultssupporting

confidence: 92%

“…Although they explain the BOLD response (Boas, Jones, Devor, Huppert, & Dale, 2008) and (slow) oscillations at a coarse level (Fantini, 2014), they do not explain the characteristics of the slow oscillations we found in our measurements. Our measurements confirm the phase difference of 1 π between the oxy and deoxy oscillation found by others (Reinhard et al, 2006; Watanabe et al, 2017). These models lack an explanation for the local (sometimes overlapping) character of the slow oscillations, its stationary aspect, their slightly different oscillation frequencies and the phase shift across the oscillating region.…”

Section: Future Directionssupporting

confidence: 92%

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Detailed view on slow sinusoidal, hemodynamic oscillations on the human brain cortex by Fourier transforming oxy/deoxy hyperspectral images

Noordmans

Blooijs

Siero

et al. 2018

Human Brain Mapping

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Slow sinusoidal, hemodynamic oscillations (SSHOs) around 0.1 Hz are frequently seen in mammalian and human brains. In four patients undergoing epilepsy surgery, subtle but robust fluctuations in oxy‐ and deoxyhemoglobin were detected using hyperspectral imaging of the cortex. These SSHOs were stationary during the entire 4 to 10 min acquisition time. By Fourier filtering the oxy‐ and deoxyhemoglobin time signals with a small bandwidth, SSHOs became visible within localized regions of the brain, with distinctive frequencies and a continuous phase variation within that region. SSHOs of deoxyhemoglobin appeared to have an opposite phase and 11% smaller amplitude with respect to the oxyhemoglobin SSHOs. Although the origin of SSHOs remains unclear, we find indications that the observed SSHOs may embody a local propagating hemodynamic wave with velocities in line with capillary blood velocities, and conceivably related to vasomotion and maintenance of adequate tissue perfusion. Hyperspectral imaging of the human cortex during surgery allow in‐depth characterization of SSHOs, and may give further insight in the nature and potential (clinical) use of SSHOs.

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Δ {normalϕ}_{Δ normalH normalb normalO - Δ normalH normalb normalR} \sim normalπ

. Therefore, the SSHO in total hemoglobin HbT (sum of HbO and HbR) is relatively small.…”

Section: Resultssupporting

confidence: 92%

Section: Future Directionssupporting

confidence: 92%

Detailed view on slow sinusoidal, hemodynamic oscillations on the human brain cortex by Fourier transforming oxy/deoxy hyperspectral images

Noordmans

Blooijs

Siero

et al. 2018

Human Brain Mapping

View full text Add to dashboard Cite

show abstract

“…variations in the blood vessels diameter) associated with spontaneous hemodynamic oscillations in different frequency bands as such as the cardiac signal (i.e. heartbeat,~1 Hz), respiration (~0.3 Hz), low frequency (LF) (Mayer wave) (~0.1 Hz) and very low frequency (VLF) oscillations (b0.1 Hz) of different physiological origin (Cheng et al, 2012;Julien, 2006;Obrig et al, 2000a;Phillip et al, 2012;Reinhard et al, 2006;Tong et al, 2011;Toronov et al, 2000;Trajkovic et al, 2011). Also oscillations in the CSF (Droste and Krauss, 1997;Feinberg and Mark, 1987;Friese et al, 2004;Gupta et al, 2010;Kao et al, 2008;Strik et al, 2002) and even periodic displacements of the brain itself (Enzmann and Pelc, 1992;Feinberg and Mark, 1987;Poncelet et al, 1992;Soellinger et al, 2007Soellinger et al, , 2009) may contribute to the non-evoked signals.…”

Section: Classification Of Signal Componentsmentioning

confidence: 99%

“…this is demonstrated by the findings that the amplitude variations of the spontaneous LF oscillation can be caused by frequency variations of respiration. Respiration with the same frequency as the LF oscillation (0.1 Hz) leads to a resonance amplification (Cheng et al, 2012;Diehl et al, 1995;Obrig et al, 2000a;Reinhard et al, 2006) and the choice of the length of the stimulation period influences the amplitude substantially (Toronov et al, 2000). Furthermore the LF oscillation seems to be interconnected with stimulus/task-evoked functional brain activity (i.e.…”

Section: Classification Of Signal Componentsmentioning

confidence: 99%

A review on continuous wave functional near-infrared spectroscopy and imaging instrumentation and methodology

Scholkmann¹,

Kleiser²,

Metz³

et al. 2014

NeuroImage

1,523

1,394

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This year marks the 20th anniversary of functional near-infrared spectroscopy and imaging (fNIRS/fNIRI). As the vast majority of commercial instruments developed until now are based on continuous wave technology, the aim of this publication is to review the current state of instrumentation and methodology of continuous wave fNIRI. For this purpose we provide an overview of the commercially available instruments and address instrumental aspects such as light sources, detectors and sensor arrangements. Methodological aspects, algorithms to calculate the concentrations of oxy-and deoxyhemoglobin and approaches for data analysis are also reviewed. From the single-location measurements of the early years, instrumentation has progressed to imaging initially in two dimensions (topography) and then three (tomography). The methods of analysis have also changed tremendously, from the simple modified Beer-Lambert law to sophisticated image reconstruction and data analysis methods used today. Due to these advances, fNIRI has become a modality that is widely used in neuroscience research and several manufacturers provide commercial instrumentation. It seems likely that fNIRI will become a clinical tool in the foreseeable future, which will enable diagnosis in single subjects. This year marks the 20th anniversary of functional near-infrared spectroscopy and imaging (fNIRS/fNIRI). As the vast majority of commercial instruments developed until now are based on continuous wave technology, the aim of this publication is to review the current state of instrumentation and methodology of continuous wave fNIRI. For this purpose we provide an overview of the commercially available instruments and address instrumental aspects such as light sources, detectors and sensor arrangements. Methodological aspects, algorithms to calculate the concentrations of oxy-and deoxyhemoglobin and approaches for data analysis are also reviewed. From the single-location measurements of the early years, instrumentation has progressed to imaging initially in two dimensions (topography) and then three (tomography). The methods of analysis have also changed tremendously, from the simple modified Beer-Lambert law to sophisticated image reconstruction and data analysis methods used today. Due to these advances, fNIRI has become a modality that is widely used in neuroscience research and several manufacturers provide commercial instrumentation. It seems likely that fNIRI will become a clinical tool in the foreseeable future, which will enable diagnosis in single subjects. Contents

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“…More recently, it was shown that in adults stable 0.1 Hz oscillations of hemodynamic parameters induced by regular breathing at a rate of 6/min, bring about cortical hemodynamic responses that follow specific phase relationships due to cerebral autoregulatory action and circulatory transit times which can be measured by NIRS [6]. With hemodynamic impairment, as in unilateral carotid obstruction, these phases were significantly changed reflecting disturbed autoregulation.…”

Section: Abpmentioning

confidence: 99%

Near-Infrared Spectroscopy can Monitor Dynamic Cerebral Autoregulation in Adults

et al. 2008

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Objective To study the correlation between a dynamic index of cerebral autoregulation assessed with blood flow velocity (FV) using transcranial Doppler, and a tissue oxygenation index (TOI) recorded with near-infrared spectroscopy (NIRS). Methods Twenty-three patients with sepsis, severe sepsis, or septic shock were monitored daily on up to four consecutive days. FV, TOI, and mean arterial blood pressure (ABP) were recorded for 60 min every day. An index of autoregulation (Mx) was calculated as the moving correlation coefficient between 10-s averaged values of FV and ABP over moving 5 min time-windows. The index Tox was evaluated as the correlation coefficient between TOI and ABP in the same way. The indices Mx and Tox, ABP and arterial partial pressure of CO 2 were averaged for each patient. Results Synchronized slow waves, presenting with periods from 20 s to 2 min, were seen in the TOI and FV of most patients, with a reasonable coherence between the signals in this bandwidth (coherence >0.5). The indices, Mx and Tox, demonstrated good correlation with each other (R = 0.81; P < 0.0001) in the whole group of patients. Both indices showed a significant (P < 0.05) tendency to indicate weaker autoregulation in the state of vasodilatation associated with greater values of arterial partial pressure of CO 2 or lower values of ABP. Conclusion NIRS shows promise for the continuous assessment of cerebral autoregulation in adults.

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Oscillatory cerebral hemodynamics—the macro- vs. microvascular level

Cited by 121 publications

References 27 publications

Detailed view on slow sinusoidal, hemodynamic oscillations on the human brain cortex by Fourier transforming oxy/deoxy hyperspectral images

Detailed view on slow sinusoidal, hemodynamic oscillations on the human brain cortex by Fourier transforming oxy/deoxy hyperspectral images

A review on continuous wave functional near-infrared spectroscopy and imaging instrumentation and methodology

Near-Infrared Spectroscopy can Monitor Dynamic Cerebral Autoregulation in Adults

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