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Functional MRI with magnetization transfer effects: Determination of BOLD and arterial blood volume changes
Author(s) -
Kim Tae,
Hendrich Kristy,
Kim SeongGi
Publication year - 2008
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.21766
Subject(s) - magnetization transfer , arterial spin labeling , cerebral blood volume , blood volume , nuclear magnetic resonance , stimulation , oxygenation , chemistry , somatosensory system , t2 relaxation , cerebral blood flow , magnetic resonance imaging , nuclear medicine , anesthesia , medicine , neuroscience , physics , radiology , psychology
The primarily intravascular magnetization transfer (MT)‐independent changes in functional MRI (fMRI) can be separated from MT‐dependent changes. This intravascular component is dominated by an arterial blood volume change (ΔCBV a ) term whenever venous contributions are minimized. Stimulation‐induced ΔCBV a can therefore be measured by a fit of signal changes to MT ratio. MT‐varied fMRI data were acquired in 13 isoflurane‐anesthetized rats during forepaw stimulation at 9.4T to simultaneously measure blood‐oxygenation‐level–dependent (BOLD) and ΔCBV a response in somatosensory cortical regions. Transverse relaxation rate change (Δ R 2 ) without MT was –0.43 ± 0.15 s −1 , and MT ratio decreased during stimulation. ΔCBV a was 0.46 ± 0.15 ml/100 g, which agrees with our previously‐presented MT‐varied arterial‐spin‐labeled data (0.42 ± 0.18 ml/100 g) in the same animals and also correlates with Δ R 2 without MT. Simulations show that ΔCBV a quantification errors due to potential venous contributions are small for our conditions. Magn Reson Med 60:1518–1523, 2008. © 2008 Wiley‐Liss, Inc.