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Approaches to Brain Stress Testing: BOLD Magnetic Resonance Imaging with Computer-Controlled Delivery of Carbon Dioxide

BACKGROUND: An impaired vascular response in the brain regionally may indicate reduced vascular reserve and vulnerability to ischemic injury. Changing the carbon dioxide (CO(2)) tension in arterial blood is commonly used as a cerebral vasoactive stimulus to assess the cerebral vascular response, cha...

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Autores principales: Mutch, W. Alan C., Mandell, Daniel M., Fisher, Joseph A., Mikulis, David J., Crawley, Adrian P., Pucci, Olivia, Duffin, James
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2012
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3489910/
https://www.ncbi.nlm.nih.gov/pubmed/23139743
http://dx.doi.org/10.1371/journal.pone.0047443
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author Mutch, W. Alan C.
Mandell, Daniel M.
Fisher, Joseph A.
Mikulis, David J.
Crawley, Adrian P.
Pucci, Olivia
Duffin, James
author_facet Mutch, W. Alan C.
Mandell, Daniel M.
Fisher, Joseph A.
Mikulis, David J.
Crawley, Adrian P.
Pucci, Olivia
Duffin, James
author_sort Mutch, W. Alan C.
collection PubMed
description BACKGROUND: An impaired vascular response in the brain regionally may indicate reduced vascular reserve and vulnerability to ischemic injury. Changing the carbon dioxide (CO(2)) tension in arterial blood is commonly used as a cerebral vasoactive stimulus to assess the cerebral vascular response, changing cerebral blood flow (CBF) by up to 5–11 percent/mmHg in normal adults. Here we describe two approaches to generating the CO(2) challenge using a computer-controlled gas blender to administer: i) a square wave change in CO(2) and, ii) a ramp stimulus, consisting of a continuously graded change in CO(2) over a range. Responses were assessed regionally by blood oxygen level dependent (BOLD) magnetic resonance imaging (MRI). METHODOLOGY/PRINCIPAL FINDINGS: We studied 8 patients with known cerebrovascular disease (carotid stenosis or occlusion) and 2 healthy subjects. The square wave stimulus was used to study the dynamics of the vascular response, while the ramp stimulus assessed the steady-state response to CO(2). Cerebrovascular reactivity (CVR) maps were registered by color coding and overlaid on the anatomical scans generated with 3 Tesla MRI to assess the corresponding BOLD signal change/mmHg change in CO(2), voxel-by-voxel. Using a fractal temporal approach, detrended fluctuation analysis (DFA) maps of the processed raw BOLD signal per voxel over the same CO(2) range were generated. Regions of BOLD signal decrease with increased CO(2) (coded blue) were seen in all of these high-risk patients, indicating regions of impaired CVR. All patients also demonstrated regions of altered signal structure on DFA maps (Hurst exponents less than 0.5; coded blue) indicative of anti-persistent noise. While ‘blue’ CVR maps remained essentially stable over the time of analysis, ‘blue’ DFA maps improved. CONCLUSIONS/SIGNIFICANCE: This combined dual stimulus and dual analysis approach may be complementary in identifying vulnerable brain regions and thus constitute a regional as well as global brain stress test.
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spelling pubmed-34899102012-11-08 Approaches to Brain Stress Testing: BOLD Magnetic Resonance Imaging with Computer-Controlled Delivery of Carbon Dioxide Mutch, W. Alan C. Mandell, Daniel M. Fisher, Joseph A. Mikulis, David J. Crawley, Adrian P. Pucci, Olivia Duffin, James PLoS One Research Article BACKGROUND: An impaired vascular response in the brain regionally may indicate reduced vascular reserve and vulnerability to ischemic injury. Changing the carbon dioxide (CO(2)) tension in arterial blood is commonly used as a cerebral vasoactive stimulus to assess the cerebral vascular response, changing cerebral blood flow (CBF) by up to 5–11 percent/mmHg in normal adults. Here we describe two approaches to generating the CO(2) challenge using a computer-controlled gas blender to administer: i) a square wave change in CO(2) and, ii) a ramp stimulus, consisting of a continuously graded change in CO(2) over a range. Responses were assessed regionally by blood oxygen level dependent (BOLD) magnetic resonance imaging (MRI). METHODOLOGY/PRINCIPAL FINDINGS: We studied 8 patients with known cerebrovascular disease (carotid stenosis or occlusion) and 2 healthy subjects. The square wave stimulus was used to study the dynamics of the vascular response, while the ramp stimulus assessed the steady-state response to CO(2). Cerebrovascular reactivity (CVR) maps were registered by color coding and overlaid on the anatomical scans generated with 3 Tesla MRI to assess the corresponding BOLD signal change/mmHg change in CO(2), voxel-by-voxel. Using a fractal temporal approach, detrended fluctuation analysis (DFA) maps of the processed raw BOLD signal per voxel over the same CO(2) range were generated. Regions of BOLD signal decrease with increased CO(2) (coded blue) were seen in all of these high-risk patients, indicating regions of impaired CVR. All patients also demonstrated regions of altered signal structure on DFA maps (Hurst exponents less than 0.5; coded blue) indicative of anti-persistent noise. While ‘blue’ CVR maps remained essentially stable over the time of analysis, ‘blue’ DFA maps improved. CONCLUSIONS/SIGNIFICANCE: This combined dual stimulus and dual analysis approach may be complementary in identifying vulnerable brain regions and thus constitute a regional as well as global brain stress test. Public Library of Science 2012-11-05 /pmc/articles/PMC3489910/ /pubmed/23139743 http://dx.doi.org/10.1371/journal.pone.0047443 Text en © 2012 Mutch et al http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
spellingShingle Research Article
Mutch, W. Alan C.
Mandell, Daniel M.
Fisher, Joseph A.
Mikulis, David J.
Crawley, Adrian P.
Pucci, Olivia
Duffin, James
Approaches to Brain Stress Testing: BOLD Magnetic Resonance Imaging with Computer-Controlled Delivery of Carbon Dioxide
title Approaches to Brain Stress Testing: BOLD Magnetic Resonance Imaging with Computer-Controlled Delivery of Carbon Dioxide
title_full Approaches to Brain Stress Testing: BOLD Magnetic Resonance Imaging with Computer-Controlled Delivery of Carbon Dioxide
title_fullStr Approaches to Brain Stress Testing: BOLD Magnetic Resonance Imaging with Computer-Controlled Delivery of Carbon Dioxide
title_full_unstemmed Approaches to Brain Stress Testing: BOLD Magnetic Resonance Imaging with Computer-Controlled Delivery of Carbon Dioxide
title_short Approaches to Brain Stress Testing: BOLD Magnetic Resonance Imaging with Computer-Controlled Delivery of Carbon Dioxide
title_sort approaches to brain stress testing: bold magnetic resonance imaging with computer-controlled delivery of carbon dioxide
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3489910/
https://www.ncbi.nlm.nih.gov/pubmed/23139743
http://dx.doi.org/10.1371/journal.pone.0047443
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