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Proton T1 relaxation times of metabolites in human occipital white and gray matter at 7 T


Correspondence to: Lijing Xin, Ph.D., Ecole Polytechnique Fédérale de Lausanne (EPFL), EPFL-SB-IPSB-LIFMET, Station 6, CH-1015 Lausanne, Switzerland. E-mail:


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. Magn Reson Med 69:931–936, 2013. © 2012 Wiley Periodicals, Inc.