Proton T1 relaxation times of metabolites in human occipital white and gray matter at 7 T.
Proton T1 relaxation times of metabolites in the human brain have not previously been published at 7 T. In this study, T1 values of CH3 and CH2 group of N-acetylaspartate and total creatine as well as nine other brain metabolites were measured in occipital white matter and gray matter at 7 T using an inversion-recovery technique combined with a newly implemented semi-adiabatic spin-echo full-intensity acquired localized spectroscopy sequence (echo time = 12 ms). The mean T1 values of metabolites in occipital white matter and gray matter ranged from 0.9 to 2.2 s. Among them, the T1 of glutathione, scyllo-inositol, taurine, phosphorylethanolamine, and N-acetylaspartylglutamate were determined for the first time in the human brain. Significant differences in T1 between white matter and gray matter were found for water (-28%), total choline (-14%), N-acetylaspartylglutamate (-29%), N-acetylaspartate (+4%), and glutamate (+8%). An increasing trend in T1 was observed when compared with previously reported values of N-acetylaspartate (CH3 ), total creatine (CH3 ), and total choline at 3 T. However, for N-acetylaspartate (CH3 ), total creatine, and total choline, no substantial differences compared to previously reported values at 9.4 T were discernible. The T1 values reported here will be useful for the quantification of metabolites and signal-to-noise optimization in human brain at 7 T.
Department of Radiology, University of Lausanne, Lausanne, Switzerland. lijing.xin@epfl.ch
Lijing
L
Xin
Benoît
B
Schaller
Vladimir
V
Mlynarik
Huanxiang
H
Lu
Rolf
R
Gruetter
D000328:Adult; D000465:Algorithms; D005260:Female; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D057054:Molecular Imaging / Q000379:methods*; D009413:Nerve Fibers, Myelinated / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism*; D009778:Occipital Lobe / Q000378:metabolism*; D011522:Protons; D055815:Young Adult
D011522:Protons