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Quantifying the blood oxygenation level dependent effect in cerebral blood volume–weighted functional MRI at 9.4T
Author(s) -
Lu Hanbing,
Scholl Clara A.,
Zuo Yantao,
Stein Elliot A.,
Yang Yihong
Publication year - 2007
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.21354
Subject(s) - blood oxygenation , cerebral blood volume , contrast (vision) , blood volume , nuclear magnetic resonance , echo time , functional magnetic resonance imaging , gradient echo , magnetic resonance imaging , spin echo , echo (communications protocol) , oxygenation , blood oxygen level dependent , nuclear medicine , neuroscience , chemistry , physics , medicine , computer science , cardiology , psychology , radiology , artificial intelligence , computer network
In cerebral blood volume (CBV)‐weighted functional MRI (fMRI) employing superparamagnetic contrast agent, iron dose and blood oxygenation level dependent (BOLD) contamination are two important issues for experimental design and CBV quantification. Both BOLD and CBV‐weighted fMRI are based upon the susceptibility effect, to which spin‐echo and gradient‐echo sequences have different sensitivities. In the present study, CBV‐weighted fMRI was conducted using spin‐echo and gradient‐echo sequences at 9.4T by systematically changing the doses of contrast agent. Results suggest that BOLD contamination is a significant component in CBV‐weighted fMRI at high field, particularly when relatively low dose of contrast agent is administered. A mathematical model was developed to quantify the extravascular (EV) BOLD effect. With a TE of 35 ms, the EV BOLD effect was estimated to account for 76 ± 12% of the observed spin‐echo fMRI signal at 9.4T. These data suggest that correcting BOLD effect may be necessary for accurately quantifying activation‐induced CBV changes at high field. Magn Reson Med 58:616–621, 2007. © 2007 Wiley‐Liss, Inc.