A novel method of quantifying hemodynamic delays to improve hemodynamic response, and CVR estimates in CO2 challenge fMRI

Yao, Jinxia Fiona; Yang, Ho-Ching; Wang, James H.; Liang, Zhenhu; Talavage, Thomas M.; Tamer, Gregory G.; Jang, Ikbeom; Tong, Yunjie

doi:10.1177/0271678x20978582

Cited by 18 publications

(37 citation statements)

References 52 publications

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“…For the correction of CO 2 fluctuations on the fMRI signal, the HRF CO 2 can be convolved with end-tidal CO 2 data, and the output regressed out of the BOLD signal (Prokopiou et al, 2019). Use of end-tidal CO 2 measurements can also be useful when the user requires creation of the estimated CO 2 arrival time at each brain region and quantification of the hemodynamic response following elevation of CO 2 (Yao et al, 2021).…”

Section: Functional Mri Of the Brainstem In Relation To Respirationmentioning

confidence: 99%

fMRI studies evaluating central respiratory control in humans

Ciumas

Rheims

Ryvlin

2022

Front. Neural Circuits

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A plethora of neural centers in the central nervous system control the fundamental respiratory pattern. This control is ensured by neurons that act as pacemakers, modulating activity through chemical control driven by changes in the O2/CO2 balance. Most of the respiratory neural centers are located in the brainstem, but difficult to localize on magnetic resonance imaging (MRI) due to their small size, lack of visually-detectable borders with neighboring areas, and significant physiological noise hampering detection of its activity with functional MRI (fMRI). Yet, several approaches make it possible to study the normal response to different abnormal stimuli or conditions such as CO2 inhalation, induced hypercapnia, volitional apnea, induced hypoxia etc. This review provides a comprehensive overview of the majority of available studies on central respiratory control in humans.

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Section: Functional Mri Of the Brainstem In Relation To Respirationmentioning

confidence: 99%

fMRI studies evaluating central respiratory control in humans

Ciumas

Rheims

Ryvlin

2022

Front. Neural Circuits

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“…The CVR, thus, represents the linear relationship of %BOLD and hypercapnic vasoactive stimulation for each voxel. 27,[47][48][49] To estimate the relative change in CBV, we first used the %DBOLD values from the hyperoxia condition (%D BOLD ho ) to estimate the M-value using the hyperoxiacalibrated BOLD model from Chiarelli et al: 50…”

Section: Fmri Data Analysismentioning

confidence: 99%

The many layers of BOLD. The effect of hypercapnic and hyperoxic stimuli on macro- and micro-vascular compartments quantified by CVR, M, and CBV across cortical depth

Schellekens

Bhogal

Roefs

et al. 2022

J Cereb Blood Flow Metab

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Ultra-high field functional magnetic resonance imaging (fMRI) offers the spatial resolution to measure neuronal activity at the scale of cortical layers. However, cortical depth dependent vascularization differences, such as a higher prevalence of macro-vascular compartments near the pial surface, have a confounding effect on depth-resolved blood-oxygen-level dependent (BOLD) fMRI signals. In the current study, we use hypercapnic and hyperoxic breathing conditions to quantify the influence of all venous vascular and micro-vascular compartments on laminar BOLD fMRI, as measured with gradient-echo (GE) and spin-echo (SE) scan sequences, respectively. We find that all venous vascular and micro-vascular compartments are capable of comparable theoretical maximum signal intensities, as represented by the M-value parameter. However, the capacity for vessel dilation, as reflected by the cerebrovascular reactivity (CVR), is approximately two and a half times larger for all venous vascular compartments combined compared to the micro-vasculature at superficial layers. Finally, there is roughly a 35% difference in estimates of CBV changes between all venous vascular and micro-vascular compartments, although this relative difference was approximately uniform across cortical depth. Thus, our results suggest that fMRI BOLD signal differences across cortical depth are likely caused by differences in dilation properties between macro- and micro-vascular compartments.

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“…Transfer function analysis can be used to identify phase, gain, and coherence metrics ( Duffin et al, 2015 ). Sinusoidal stimuli may be used ( Blockley et al, 2011 ), and the linear fit between the observed BOLD signal and the arrival-time adjusted P ET CO 2 convolved with the hemodynamic response function ( Yao et al, 2021 ).…”

Section: A New Cvr Metric: Speed Of Responsementioning

confidence: 99%

Measuring Cerebrovascular Reactivity: Sixteen Avoidable Pitfalls

et al. 2021

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An increase in arterial PCO2 is the most common stressor used to increase cerebral blood flow for assessing cerebral vascular reactivity (CVR). That CO2 is readily obtained, inexpensive, easy to administer, and safe to inhale belies the difficulties in extracting scientifically and clinically relevant information from the resulting flow responses. Over the past two decades, we have studied more than 2,000 individuals, most with cervical and cerebral vascular pathology using CO2 as the vasoactive agent and blood oxygen-level-dependent magnetic resonance imaging signal as the flow surrogate. The ability to deliver different forms of precise hypercapnic stimuli enabled systematic exploration of the blood flow-related signal changes. We learned the effect on CVR of particular aspects of the stimulus such as the arterial partial pressure of oxygen, the baseline PCO2, and the magnitude, rate, and pattern of its change. Similarly, we learned to interpret aspects of the flow response such as its magnitude, and the speed and direction of change. Finally, we were able to test whether the response falls into a normal range. Here, we present a review of our accumulated insight as 16 “lessons learned.” We hope many of these insights are sufficiently general to apply to a range of types of CO2-based vasoactive stimuli and perfusion metrics used for CVR.

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A novel method of quantifying hemodynamic delays to improve hemodynamic response, and CVR estimates in CO2 challenge fMRI

Cited by 18 publications

References 52 publications

fMRI studies evaluating central respiratory control in humans

fMRI studies evaluating central respiratory control in humans

The many layers of BOLD. The effect of hypercapnic and hyperoxic stimuli on macro- and micro-vascular compartments quantified by CVR, M, and CBV across cortical depth

Measuring Cerebrovascular Reactivity: Sixteen Avoidable Pitfalls

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