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Functional quantitative susceptibility mapping (fQSM) of rat brain during flashing light stimulation.
- Source :
-
NeuroImage [Neuroimage] 2021 Jun; Vol. 233, pp. 117924. Date of Electronic Publication: 2021 Mar 19. - Publication Year :
- 2021
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Abstract
- Functional magnetic resonance imaging (fMRI) based on the blood oxygenation level-dependent (BOLD) contrast has become an indispensable tool in neuroscience. However, the BOLD signal is nonlocal, lacking quantitative measurement of oxygenation fluctuation. This preclinical study aimed to introduced functional quantitative susceptibility mapping (fQSM) to complement BOLD-fMRI to quantitatively assess the local susceptibility and venous oxygen saturation (SvO <subscript>2</subscript> ). Rats were subjected to a 5 Hz flashing light and the different inhaled oxygenation levels (30% and 100%) were used to observe the venous susceptibility to quantify SvO <subscript>2</subscript> . Phase information was extracted to produce QSM, and the activation responses of magnitude (conventional BOLD) and the QSM time-series were analyzed. During light stimulation, the susceptibility change of fQSM was four times larger than the BOLD signal change in both inhalation oxygenation conditions. Moreover, the responses in the fQSM map were more restricted to the visual pathway, such as the lateral geniculate nucleus and superior colliculus, compared with the relatively diffuse distributions in the BOLD map. Also, the calibrated SvO <subscript>2</subscript> was approximately 84% (88%) when the task was on, 83% (87%) when the task was off during 30% (and during 100%) oxygen inhalation. This is the first fQSM study in a small animal model and increases our understanding of fQSM in the brains of small animals. This study demonstrated the feasibility, sensitivity, and specificity of fQSM using light stimulus, as fQSM provides quantitative clues as well as localized information, complementing the defects of BOLD-fMRI. In addition to neural activity, fQSM also assesses SvO <subscript>2</subscript> as supplementary information while BOLD-fMRI dose not. Accordingly, the fQSM technique could be a useful quantitative tool for functional studies, such as longitudinal follow up of neurodegenerative diseases, functional recovery after brain surgery, and negative BOLD studies.<br />Competing Interests: Declaration of Competing Interest None.<br /> (Copyright © 2021. Published by Elsevier Inc.)
- Subjects :
- Animals
Brain diagnostic imaging
Brain physiology
Geniculate Bodies physiology
Male
Rats
Rats, Sprague-Dawley
Superior Colliculi physiology
Visual Pathways physiology
Brain Mapping methods
Geniculate Bodies diagnostic imaging
Magnetic Resonance Imaging methods
Photic Stimulation methods
Superior Colliculi diagnostic imaging
Visual Pathways diagnostic imaging
Subjects
Details
- Language :
- English
- ISSN :
- 1095-9572
- Volume :
- 233
- Database :
- MEDLINE
- Journal :
- NeuroImage
- Publication Type :
- Academic Journal
- Accession number :
- 33753240
- Full Text :
- https://doi.org/10.1016/j.neuroimage.2021.117924