Functional magnetic resonance imaging of the human brain based on signal enhancement by extravascular protons (SEEP fMRI)

Functional magnetic resonance imaging (fMRI) studies of the human brain were carried out at 3 Tesla to investigate an fMRI contrast mechanism that does not arise from the blood oxygen‐level dependent (BOLD) effect. This contrast mechanism, signal enhancement by extravascular protons (SEEP), involves...

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Bibliographic Details
Published in:Magnetic resonance in medicine 2003-03, Vol.49 (3), p.433-439
Main Authors: Stroman, P.W., Tomanek, B., Krause, V., Frankenstein, U.N., Malisza, K.L.
Format: Article
Language:English
Subjects:
Biological and medical sciences
BOLD
brain
Brain - physiology
fMRI
human
Humans
Image Enhancement - methods
In Vitro Techniques
Investigative techniques, diagnostic techniques (general aspects)
magnetic resonance
Magnetic Resonance Imaging - methods
Medical sciences
Nervous system
Neurons - physiology
Protons
Radiodiagnosis. Nmr imagery. Nmr spectrometry
SEEP
Sensitivity and Specificity
Signal Processing, Computer-Assisted
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Summary:Functional magnetic resonance imaging (fMRI) studies of the human brain were carried out at 3 Tesla to investigate an fMRI contrast mechanism that does not arise from the blood oxygen‐level dependent (BOLD) effect. This contrast mechanism, signal enhancement by extravascular protons (SEEP), involves only proton‐density changes and was recently demonstrated to contribute to fMRI signal changes in the spinal cord. In the present study it is hypothesized that SEEP fMRI can be used to identify areas of neuronal activity in the brain with as much sensitivity and precision as can be achieved with BOLD fMRI. A detailed analysis of the areas of activity, signal intensity time courses, and the contrast‐to‐noise ratio (CNR), is also presented and compared with the BOLD fMRI results. Experiments were carried out with subjects performing a simple finger‐touching task, or observing an alternating checkerboard pattern. Data were acquired using a conventional BOLD fMRI method (gradient‐echo (GE) EPI, TE = 30 ms), a conventional method with reduced BOLD sensitivity (GE‐EPI, TE = 12 ms), and SEEP fMRI (spin‐echo (SE) EPI, TE = 22 ms). The results of this study demonstrate that SEEP fMRI may provide better spatial localization of areas of neuronal activity, and a higher CNR than conventional BOLD fMRI, and has the added benefit of lower sensitivity to field inhomogeneities. Magn Reson Med 49:433–439, 2003. © 2003 Wiley‐Liss, Inc.
ISSN:0740-3194
1522-2594
DOI:10.1002/mrm.10831