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  Vascular autorescaling of fMRI (VasA fMRI) improves sensitivity of population studies: A pilot study

Kazan, S. M., Mohammadi, S., Callaghan, M. F., Flandin, G., Huber, L., Leech, R., et al. (2016). Vascular autorescaling of fMRI (VasA fMRI) improves sensitivity of population studies: A pilot study. NeuroImage, 124(A), 794-805. doi:10.1016/j.neuroimage.2015.09.033.

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Kazan, Samira M.1, Author
Mohammadi, Siawoosh1, Author
Callaghan, Martina F.1, Author
Flandin, Guillaume1, Author
Huber, Laurentius2, Author           
Leech, Robert3, Author
Kennerly, Aneurin4, Author
Windischberger, Christian5, Author
Weiskopf, Nikolaus1, 6, Author           
1Wellcome Trust Centre for Neuroimaging, University College London, United Kingdom, ou_persistent22              
2Methods and Development Unit Nuclear Magnetic Resonance, MPI for Human Cognitive and Brain Sciences, Max Planck Society, ou_634558              
3Computational, Cognitive and Clinical Neuroimaging Laboratory, Imperial College London, United Kingdom, ou_persistent22              
4Department of Psychology, University of Sheffield, United Kingdom, ou_persistent22              
5MR Centre of Excellence, Medical University of Vienna, Austria, ou_persistent22              
6Department Neurophysics (Weiskopf), MPI for Human Cognitive and Brain Sciences, Max Planck Society, ou_2205649              


Free keywords: ALFF; Autorescaling; BOLD fMRI; Group analysis; Vascularization differences
 Abstract: The blood oxygenation level-dependent (BOLD) signal is widely used for functional magnetic resonance imaging (fMRI) of brain function in health and disease. The statistical power of fMRI group studies is significantly hampered by high inter-subject variance due to differences in baseline vascular physiology. Several methods have been proposed to account for physiological vascularization differences between subjects and hence improve the sensitivity in group studies. However, these methods require the acquisition of additional reference scans (such as a full resting-state fMRI session or ASL-based calibrated BOLD). We present a vascular autorescaling (VasA) method, which does not require any additional reference scans. VasA is based on the observation that slow oscillations (<0.1Hz) in arterial blood CO2 levels occur naturally due to changes in respiration patterns. These oscillations yield fMRI signal changes whose amplitudes reflect the blood oxygenation levels and underlying local vascularization and vascular responsivity. VasA estimates proxies of the amplitude of these CO2-driven oscillations directly from the residuals of task-related fMRI data without the need for reference scans. The estimates are used to scale the amplitude of task-related fMRI responses, to account for vascular differences. The VasA maps compared well to cerebrovascular reactivity (CVR) maps and cerebral blood volume maps based on vascular space occupancy (VASO) measurements in four volunteers, speaking to the physiological vascular basis of VasA. VasA was validated in a wide variety of tasks in 138 volunteers. VasA increased t-scores by up to 30% in specific brain areas such as the visual cortex. The number of activated voxels was increased by up to 200% in brain areas such as the orbital frontal cortex while still controlling the nominal false-positive rate. VasA fMRI outperformed previously proposed rescaling approaches based on resting-state fMRI data and can be readily applied to any task-related fMRI data set, even retrospectively.


Language(s): eng - English
 Dates: 2015-04-092015-09-172015-09-282016-01-01
 Publication Status: Published in print
 Pages: -
 Publishing info: -
 Table of Contents: -
 Rev. Type: Peer
 Identifiers: DOI: 10.1016/j.neuroimage.2015.09.033
PMID: 26416648
PMC: PMC4655941
Other: Epub 2015
 Degree: -



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Project name : Non-invasive in vivo histology in health and disease using Magnetic Resonance Imaging (MRI) / HMRI
Grant ID : 616905
Funding program : FP7 (ERC-2013-CoG)
Funding organization : European Research Council
Project name : -
Grant ID : 091593/Z/10/Z
Funding program : -
Funding organization : Wellcome Trust (WT)
Project name : -
Grant ID : 1U54MH091657
Funding program : -
Funding organization : 16 NIH Institutes and Centers
Project name : -
Grant ID : -
Funding program : -
Funding organization : McDonnell Center for Systems Neuroscience at Washington University
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Grant ID : G1002194
Funding program : -
Funding organization : Medical Research Council (MRC)

Source 1

Title: NeuroImage
Source Genre: Journal
Publ. Info: Orlando, FL : Academic Press
Pages: - Volume / Issue: 124 (A) Sequence Number: - Start / End Page: 794 - 805 Identifier: ISSN: 1053-8119
CoNE: https://pure.mpg.de/cone/journals/resource/954922650166