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ABSTRACT: Purpose
To develop an efficient MRI approach to estimate the nonwater proton fraction (f) in human brain.Methods
We implement a brief, efficient magnetization transfer (MT) pulse that selectively saturates the magnetization of the (semi-) solid protons, and monitor the transfer of this saturation to the water protons as a function of delay after saturation.Results
Analysis of the transient MT effect with two-pool model allowed robust extraction of f at both 3 and 7 T. This required estimating the longitudinal relaxation rate constant (R1,MP and R1,WP ) for both proton pools, which was achieved with the assumption of uniform R1,MP and R1,WP across brain tissues. Resulting values of f were approximately 50% higher than reported previously, which is partly attributed to MT-pulse efficiency and R1,MP being higher than assumed previously.Conclusion
Experiments performed on human brain in vivo at 3 and 7 T demonstrate the ability of the method to robustly determine f in a scan time of approximately 5 min. Magn Reson Med 77:2174-2185, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
SUBMITTER: van Gelderen P
PROVIDER: S-EPMC5183566 | biostudies-literature | 2017 Jun
REPOSITORIES: biostudies-literature
van Gelderen Peter P Jiang Xu X Duyn Jeff H JH
Magnetic resonance in medicine 20160625 6
<h4>Purpose</h4>To develop an efficient MRI approach to estimate the nonwater proton fraction (f) in human brain.<h4>Methods</h4>We implement a brief, efficient magnetization transfer (MT) pulse that selectively saturates the magnetization of the (semi-) solid protons, and monitor the transfer of this saturation to the water protons as a function of delay after saturation.<h4>Results</h4>Analysis of the transient MT effect with two-pool model allowed robust extraction of f at both 3 and 7 T. Thi ...[more]