Contrasting Measures of Cerebrovascular Reactivity Between MRI and Doppler: A Cross-Sectional Study of Younger and Older Healthy Individuals
Cerebrovascular reactivity (CVR) is used as an outcome measure of brain health. Traditionally, lower CVR is associated with ageing, poor fitness and brain-related conditions (e.g. stroke, dementia). Indeed, CVR is suggested as a biomarker for disease risk. However, recent findings report conflicting...
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2021-04-01
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Online Access: | https://www.frontiersin.org/articles/10.3389/fphys.2021.656746/full |
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Article |
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DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Claire V. Burley Claire V. Burley Claire V. Burley Susan T. Francis Kate N. Thomas Anna C. Whittaker Anna C. Whittaker Samuel J. E. Lucas Samuel J. E. Lucas Karen J. Mullinger Karen J. Mullinger Karen J. Mullinger |
spellingShingle |
Claire V. Burley Claire V. Burley Claire V. Burley Susan T. Francis Kate N. Thomas Anna C. Whittaker Anna C. Whittaker Samuel J. E. Lucas Samuel J. E. Lucas Karen J. Mullinger Karen J. Mullinger Karen J. Mullinger Contrasting Measures of Cerebrovascular Reactivity Between MRI and Doppler: A Cross-Sectional Study of Younger and Older Healthy Individuals Frontiers in Physiology cerebrovascular reactivity transcranial Doppler magnetic resonance imaging ageing brain vascular health cerebral blood flow |
author_facet |
Claire V. Burley Claire V. Burley Claire V. Burley Susan T. Francis Kate N. Thomas Anna C. Whittaker Anna C. Whittaker Samuel J. E. Lucas Samuel J. E. Lucas Karen J. Mullinger Karen J. Mullinger Karen J. Mullinger |
author_sort |
Claire V. Burley |
title |
Contrasting Measures of Cerebrovascular Reactivity Between MRI and Doppler: A Cross-Sectional Study of Younger and Older Healthy Individuals |
title_short |
Contrasting Measures of Cerebrovascular Reactivity Between MRI and Doppler: A Cross-Sectional Study of Younger and Older Healthy Individuals |
title_full |
Contrasting Measures of Cerebrovascular Reactivity Between MRI and Doppler: A Cross-Sectional Study of Younger and Older Healthy Individuals |
title_fullStr |
Contrasting Measures of Cerebrovascular Reactivity Between MRI and Doppler: A Cross-Sectional Study of Younger and Older Healthy Individuals |
title_full_unstemmed |
Contrasting Measures of Cerebrovascular Reactivity Between MRI and Doppler: A Cross-Sectional Study of Younger and Older Healthy Individuals |
title_sort |
contrasting measures of cerebrovascular reactivity between mri and doppler: a cross-sectional study of younger and older healthy individuals |
publisher |
Frontiers Media S.A. |
series |
Frontiers in Physiology |
issn |
1664-042X |
publishDate |
2021-04-01 |
description |
Cerebrovascular reactivity (CVR) is used as an outcome measure of brain health. Traditionally, lower CVR is associated with ageing, poor fitness and brain-related conditions (e.g. stroke, dementia). Indeed, CVR is suggested as a biomarker for disease risk. However, recent findings report conflicting associations between ageing or fitness and CVR measures. Inconsistent findings may relate to different neuroimaging modalities used, which include transcranial Doppler (TCD) and blood-oxygen-level-dependant (BOLD) contrast magnetic resonance imaging (MRI). We assessed the relationship between CVR metrics derived from two common imaging modalities, TCD and BOLD MRI, within the same individuals and with expected significant differences (i.e., younger vs. older) to maximise the expected spread in measures. We conducted two serial studies using TCD- and MRI-derived measures of CVR (via inspired 5% CO2 in air). Study 1 compared 20 younger (24 ± 7 years) with 15 older (66 ± 7 years) participants, Study 2 compared 10 younger (22 ± 2 years) with 10 older (72 ± 4 years) participants. Combining the main measures across studies, no significant correlation (r = 0.15, p = 0.36) was observed between individual participant TCD- and BOLD-CVR measures. Further, these measures showed differential effects between age groups; with TCD-CVR higher in the older compared to younger group (4 ± 1 vs. 3 ± 1 %MCAv/mmHg PETCO2; p < 0.05, Hedges’ g = 0.75), whereas BOLD-CVR showed no difference (p = 0.104, Hedges’ g = 0.38). In Study 2 additional measures were obtained to understand the origin of the discrepancy: phase contrast angiography (PCA) MRI of the middle cerebral artery, showed a significantly lower blood flow (but not velocity) CVR response in older compared with younger participants (p > 0.05, Hedges’ g = 1.08). The PCA CVR metrics did not significantly correlate with the BOLD- or TCD-CVR measures. The differing CVR observations between imaging modalities were despite expected, correlated (r = 0.62–0.82), age-related differences in resting CBF measures across modalities. Taken together, findings across both studies show no clear relationship between TCD- and BOLD-CVR measures. We hypothesize that CVR differences between imaging modalities are in part due to the aspects of the vascular tree that are assessed (TCD:arteries; BOLD:venules/veins). Further work is needed to understand the between-modality CVR response differences, but caution is needed when comparing CVR metrics derived from different imaging modalities. |
topic |
cerebrovascular reactivity transcranial Doppler magnetic resonance imaging ageing brain vascular health cerebral blood flow |
url |
https://www.frontiersin.org/articles/10.3389/fphys.2021.656746/full |
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doaj-43b182a74940423d8afb8cd7a95f97af2021-04-12T07:12:07ZengFrontiers Media S.A.Frontiers in Physiology1664-042X2021-04-011210.3389/fphys.2021.656746656746Contrasting Measures of Cerebrovascular Reactivity Between MRI and Doppler: A Cross-Sectional Study of Younger and Older Healthy IndividualsClaire V. Burley0Claire V. Burley1Claire V. Burley2Susan T. Francis3Kate N. Thomas4Anna C. Whittaker5Anna C. Whittaker6Samuel J. E. Lucas7Samuel J. E. Lucas8Karen J. Mullinger9Karen J. Mullinger10Karen J. Mullinger11School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, United KingdomCentre for Human Brain Health, University of Birmingham, Birmingham, United KingdomDementia Centre for Research Collaboration, School of Psychiatry, University of New South Wales, Sydney, NSW, AustraliaSir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, United KingdomDepartment of Surgical Sciences, Dunedin School of Medicine, University of Otago, Dunedin, New ZealandSchool of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, United KingdomFaculty of Health Sciences and Sport, University of Stirling, Stirling, United KingdomSchool of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, United KingdomCentre for Human Brain Health, University of Birmingham, Birmingham, United KingdomCentre for Human Brain Health, University of Birmingham, Birmingham, United KingdomSir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, United KingdomSchool of Psychology, University of Birmingham, Birmingham, United KingdomCerebrovascular reactivity (CVR) is used as an outcome measure of brain health. Traditionally, lower CVR is associated with ageing, poor fitness and brain-related conditions (e.g. stroke, dementia). Indeed, CVR is suggested as a biomarker for disease risk. However, recent findings report conflicting associations between ageing or fitness and CVR measures. Inconsistent findings may relate to different neuroimaging modalities used, which include transcranial Doppler (TCD) and blood-oxygen-level-dependant (BOLD) contrast magnetic resonance imaging (MRI). We assessed the relationship between CVR metrics derived from two common imaging modalities, TCD and BOLD MRI, within the same individuals and with expected significant differences (i.e., younger vs. older) to maximise the expected spread in measures. We conducted two serial studies using TCD- and MRI-derived measures of CVR (via inspired 5% CO2 in air). Study 1 compared 20 younger (24 ± 7 years) with 15 older (66 ± 7 years) participants, Study 2 compared 10 younger (22 ± 2 years) with 10 older (72 ± 4 years) participants. Combining the main measures across studies, no significant correlation (r = 0.15, p = 0.36) was observed between individual participant TCD- and BOLD-CVR measures. Further, these measures showed differential effects between age groups; with TCD-CVR higher in the older compared to younger group (4 ± 1 vs. 3 ± 1 %MCAv/mmHg PETCO2; p < 0.05, Hedges’ g = 0.75), whereas BOLD-CVR showed no difference (p = 0.104, Hedges’ g = 0.38). In Study 2 additional measures were obtained to understand the origin of the discrepancy: phase contrast angiography (PCA) MRI of the middle cerebral artery, showed a significantly lower blood flow (but not velocity) CVR response in older compared with younger participants (p > 0.05, Hedges’ g = 1.08). The PCA CVR metrics did not significantly correlate with the BOLD- or TCD-CVR measures. The differing CVR observations between imaging modalities were despite expected, correlated (r = 0.62–0.82), age-related differences in resting CBF measures across modalities. Taken together, findings across both studies show no clear relationship between TCD- and BOLD-CVR measures. We hypothesize that CVR differences between imaging modalities are in part due to the aspects of the vascular tree that are assessed (TCD:arteries; BOLD:venules/veins). Further work is needed to understand the between-modality CVR response differences, but caution is needed when comparing CVR metrics derived from different imaging modalities.https://www.frontiersin.org/articles/10.3389/fphys.2021.656746/fullcerebrovascular reactivitytranscranial Dopplermagnetic resonance imagingageingbrain vascular healthcerebral blood flow |