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Cerebrovascular Resistance in Healthy Aging and Mild Cognitive Impairment
Measures of cerebrovascular reactivity (CVR) are used to judge the health of the brain vasculature. In this study, we report the use of several different analyses of blood oxygen dependent (BOLD) fMRI responses to CO(2) to provide a number of metrics of CVR based on the sigmoidal resistance response...
Autores principales: | , , , , , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Frontiers Media S.A.
2019
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6474328/ https://www.ncbi.nlm.nih.gov/pubmed/31031616 http://dx.doi.org/10.3389/fnagi.2019.00079 |
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author | McKetton, Larissa Cohn, Melanie Tang-Wai, David F. Sobczyk, Olivia Duffin, James Holmes, Kenneth R. Poublanc, Julien Sam, Kevin Crawley, Adrian P. Venkatraghavan, Lashmi Fisher, Joseph A. Mikulis, David J. |
author_facet | McKetton, Larissa Cohn, Melanie Tang-Wai, David F. Sobczyk, Olivia Duffin, James Holmes, Kenneth R. Poublanc, Julien Sam, Kevin Crawley, Adrian P. Venkatraghavan, Lashmi Fisher, Joseph A. Mikulis, David J. |
author_sort | McKetton, Larissa |
collection | PubMed |
description | Measures of cerebrovascular reactivity (CVR) are used to judge the health of the brain vasculature. In this study, we report the use of several different analyses of blood oxygen dependent (BOLD) fMRI responses to CO(2) to provide a number of metrics of CVR based on the sigmoidal resistance response to CO(2). To assess possible differences in these metrics with age, we compiled atlases reflecting voxel-wise means and standard deviations for four different age ranges and for a group of patients with mild cognitive impairment (MCI) and compared them. Sixty-seven subjects were recruited for this study and scanned at 3T field strength. Of those, 51 healthy control volunteers between the ages of 18–83 were recruited, and 16 (MCI) subjects between the ages of 61–83 were recruited. Testing was carried out using an automated computer-controlled gas blender to induce hypercapnia in a step and ramp paradigm while monitoring end-tidal partial pressures of CO(2). Surprisingly, some resistance sigmoid parameters in the oldest control group were increased compared to the youngest control group. Resistance amplitude maps showed increases in clusters within the temporal cortex, thalamus, corpus callosum and brainstem, and resistance reserve maps showed increases in clusters within the cingulate cortex, frontal gyrus, and corpus callosum. These findings suggest that some aspects of vascular reactivity in parts of the brain are initially maintained with age but then may increase in later years. We found significant reductions in all resistance sigmoid parameters (amplitude, reserve, sensitivity, midpoint, and range) when comparing MCI patients to controls. Additionally, in controls and in MCI patients, amplitude, range, reserve, and sensitivity in white matter (WM) was significantly reduced compared to gray matter (GM). WM midpoints were significantly above those of GM. Our general conclusion is that vascular regulation in terms of cerebral blood flow (CBF) responsiveness to CO(2) is not significantly affected by age, but is reduced in MCI. These changes in cerebrovascular regulation demonstrate the value of resistance metrics for mapping areas of dysregulated blood flow in individuals with MCI. They may also be of value in the investigation of patients with vascular risk factors at risk for developing vascular dementia. |
format | Online Article Text |
id | pubmed-6474328 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2019 |
publisher | Frontiers Media S.A. |
record_format | MEDLINE/PubMed |
spelling | pubmed-64743282019-04-26 Cerebrovascular Resistance in Healthy Aging and Mild Cognitive Impairment McKetton, Larissa Cohn, Melanie Tang-Wai, David F. Sobczyk, Olivia Duffin, James Holmes, Kenneth R. Poublanc, Julien Sam, Kevin Crawley, Adrian P. Venkatraghavan, Lashmi Fisher, Joseph A. Mikulis, David J. Front Aging Neurosci Neuroscience Measures of cerebrovascular reactivity (CVR) are used to judge the health of the brain vasculature. In this study, we report the use of several different analyses of blood oxygen dependent (BOLD) fMRI responses to CO(2) to provide a number of metrics of CVR based on the sigmoidal resistance response to CO(2). To assess possible differences in these metrics with age, we compiled atlases reflecting voxel-wise means and standard deviations for four different age ranges and for a group of patients with mild cognitive impairment (MCI) and compared them. Sixty-seven subjects were recruited for this study and scanned at 3T field strength. Of those, 51 healthy control volunteers between the ages of 18–83 were recruited, and 16 (MCI) subjects between the ages of 61–83 were recruited. Testing was carried out using an automated computer-controlled gas blender to induce hypercapnia in a step and ramp paradigm while monitoring end-tidal partial pressures of CO(2). Surprisingly, some resistance sigmoid parameters in the oldest control group were increased compared to the youngest control group. Resistance amplitude maps showed increases in clusters within the temporal cortex, thalamus, corpus callosum and brainstem, and resistance reserve maps showed increases in clusters within the cingulate cortex, frontal gyrus, and corpus callosum. These findings suggest that some aspects of vascular reactivity in parts of the brain are initially maintained with age but then may increase in later years. We found significant reductions in all resistance sigmoid parameters (amplitude, reserve, sensitivity, midpoint, and range) when comparing MCI patients to controls. Additionally, in controls and in MCI patients, amplitude, range, reserve, and sensitivity in white matter (WM) was significantly reduced compared to gray matter (GM). WM midpoints were significantly above those of GM. Our general conclusion is that vascular regulation in terms of cerebral blood flow (CBF) responsiveness to CO(2) is not significantly affected by age, but is reduced in MCI. These changes in cerebrovascular regulation demonstrate the value of resistance metrics for mapping areas of dysregulated blood flow in individuals with MCI. They may also be of value in the investigation of patients with vascular risk factors at risk for developing vascular dementia. Frontiers Media S.A. 2019-04-12 /pmc/articles/PMC6474328/ /pubmed/31031616 http://dx.doi.org/10.3389/fnagi.2019.00079 Text en Copyright © 2019 McKetton, Cohn, Tang-Wai, Sobczyk, Duffin, Holmes, Poublanc, Sam, Crawley, Venkatraghavan, Fisher and Mikulis. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. |
spellingShingle | Neuroscience McKetton, Larissa Cohn, Melanie Tang-Wai, David F. Sobczyk, Olivia Duffin, James Holmes, Kenneth R. Poublanc, Julien Sam, Kevin Crawley, Adrian P. Venkatraghavan, Lashmi Fisher, Joseph A. Mikulis, David J. Cerebrovascular Resistance in Healthy Aging and Mild Cognitive Impairment |
title | Cerebrovascular Resistance in Healthy Aging and Mild Cognitive Impairment |
title_full | Cerebrovascular Resistance in Healthy Aging and Mild Cognitive Impairment |
title_fullStr | Cerebrovascular Resistance in Healthy Aging and Mild Cognitive Impairment |
title_full_unstemmed | Cerebrovascular Resistance in Healthy Aging and Mild Cognitive Impairment |
title_short | Cerebrovascular Resistance in Healthy Aging and Mild Cognitive Impairment |
title_sort | cerebrovascular resistance in healthy aging and mild cognitive impairment |
topic | Neuroscience |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6474328/ https://www.ncbi.nlm.nih.gov/pubmed/31031616 http://dx.doi.org/10.3389/fnagi.2019.00079 |
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