Document Detail


Robustly measuring vascular reactivity differences with breath-hold: normalising stimulus-evoked and resting state BOLD fMRI data.
MedLine Citation:
PMID:  20682354     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Inter-subject differences in local cerebral blood flow (CBF) and cerebral blood volume (CBV) contribute to differences in BOLD signal reactivity and, therefore, unmodelled variance in group level fMRI analyses. A simple way of elevating blood CO(2) concentrations to characterise subject differences in vascular reactivity is through breath-holds but two aspects of this measure are often neglected: (1) breath-holds are usually modelled as blocks even though CO(2) accumulates over time and (2) increases in CO(2) differ between subjects. This study demonstrates that the BOLD breath-hold response is best modelled by convolving the end-tidal CO(2) trace with a standard haemodynamic response function and including its temporal derivative. Inclusion of the BOLD breath-hold response as a voxel-dependent covariate in a group level analysis increases the spatial extent of activation in stimulus evoked and resting state datasets. By expressing the BOLD breath-hold response as a percentage signal increase with respect to an absolute change in the partial pressure of CO(2) (expressed in mmHg), the spatial extent of stimulus-evoked activation is further improved. This demonstrates that individual end-tidal CO(2) increases to breath-hold should be accounted for to provide an accurate measure of vascular reactivity resulting in more statistically active voxels in group level analyses.
Authors:
Kevin Murphy; Ashley D Harris; Richard G Wise
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2010-08-01
Journal Detail:
Title:  NeuroImage     Volume:  54     ISSN:  1095-9572     ISO Abbreviation:  Neuroimage     Publication Date:  2011 Jan 
Date Detail:
Created Date:  2010-10-22     Completed Date:  2011-01-19     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9215515     Medline TA:  Neuroimage     Country:  United States    
Other Details:
Languages:  eng     Pagination:  369-79     Citation Subset:  IM    
Copyright Information:
Copyright © 2010 Elsevier Inc. All rights reserved.
Affiliation:
Cardiff University Brain Research Imaging Centre (CUBRIC), School of Psychology, Cardiff University, Cardiff, UK. murphyk2@cardiff.ac.uk
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MeSH Terms
Descriptor/Qualifier:
Adult
Analysis of Variance
Blood Volume
Brain / physiology
Brain Mapping
Breath Tests
Carbon Dioxide / blood*
Cerebrovascular Circulation / physiology*
Humans
Magnetic Resonance Imaging / methods*
Maximal Voluntary Ventilation / physiology
Oxygen / blood
Regression Analysis
Respiratory Mechanics / physiology
Rest / physiology
Tidal Volume
Grant Support
ID/Acronym/Agency:
//Medical Research Council
Chemical
Reg. No./Substance:
124-38-9/Carbon Dioxide; 7782-44-7/Oxygen

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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