13C MRS of human brain at 7 Tesla using [2-13C]glucose infusion and low power broadband stochastic proton decoupling

PurposeCarbon-13 (C-13) MR spectroscopy (MRS) of the human brain at 7 Tesla (T) may pose patient safety issues due to high radiofrequency (RF) power deposition for proton decoupling. The purpose of present work is to study the feasibility of in vivo C-13 MRS of human brain at 7 T using broadband low RF power proton decoupling. MethodsCarboxylic/amide C-13 MRS of human brain by broadband stochastic proton decoupling was demonstrated on a 7 T scanner. RF safety was evaluated using the finite-difference time-domain method. C-13 signal enhancement by nuclear Overhauser effect (NOE) and proton decoupling was evaluated in both phantoms and in vivo. ResultsAt 7 T, the peak amplitude of carboxylic/amide C-13 signals was increased by a factor of greater than 4 due to the combined effects of NOE and proton decoupling. The 7 T C-13 MRS technique used decoupling power and average transmit power of less than 35 watts (W) and 3.6 W, respectively. ConclusionIn vivo C-13 MRS studies of human brain can be performed at 7 T, well below the RF safety threshold, by detecting carboxylic/amide carbons with broadband stochastic proton decoupling. Magn Reson Med 75:954-961, 2016. (c) 2015 Wiley Periodicals, Inc.