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

Magn Reson Med. 2016 Mar;75(3):954-61. doi: 10.1002/mrm.25721. Epub 2015 Apr 27.

Abstract

Purpose: Carbon-13 ((13)C) 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 (13)C MRS of human brain at 7 T using broadband low RF power proton decoupling.

Methods: Carboxylic/amide (13)C 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. (13)C signal enhancement by nuclear Overhauser effect (NOE) and proton decoupling was evaluated in both phantoms and in vivo.

Results: At 7 T, the peak amplitude of carboxylic/amide (13)C signals was increased by a factor of greater than 4 due to the combined effects of NOE and proton decoupling. The 7 T (13)C MRS technique used decoupling power and average transmit power of less than 35 watts (W) and 3.6 W, respectively.

Conclusion: In vivo (13)C 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.

Keywords: 13C MRS; 7 T; human brain; stochastic decoupling.

Publication types

  • Research Support, N.I.H., Intramural

MeSH terms

  • Brain / metabolism*
  • Brain / physiology
  • Brain Chemistry
  • Carbon Isotopes / analysis
  • Carbon Isotopes / chemistry
  • Carbon Isotopes / metabolism
  • Glucose / chemistry
  • Glucose / metabolism*
  • Head / physiology
  • Humans
  • Image Processing, Computer-Assisted / methods*
  • Magnetic Resonance Imaging / methods*
  • Phantoms, Imaging
  • Signal Processing, Computer-Assisted*
  • Stochastic Processes

Substances

  • Carbon Isotopes
  • Glucose