Measurement of N-acetylaspartylglutamate in the human frontal brain by 1H-MRS at 7 T

Changho Choi, Subroto Ghose, Jinsoo Uh, Aditya Patel, Ivan E. Dimitrov, Hanzhang Lu, Deborah Douglas, Sandeep Ganji

Research output: Contribution to journalArticlepeer-review

17 Scopus citations


N-Acetylaspartylglutamate in human brain has been measured with difference editing at 7 T. The CH2 proton resonances (∼2.5 ppm) of the aspartyl groups of N-acetylaspartylglutamate and N-acetylaspartate were difference edited (MEGA) using 20-msec gaussian radiofrequency pulses for selective 180° rotations of the coupling partners at 4.61 and 4.38 ppm, respectively. The echo time of the editing sequence, 108 msec, was obtained in phantom tests. Single-voxel localized in vivo measurements were conducted in the medial prefrontal and right frontal cortices of five healthy volunteers. The gray and white matter fractions within the voxels were obtained from T 1-weighted image segmentation. Using linear regression of the metabolite concentration vs. fractional white matter contents within the voxels, the N-acetylaspartylglutamate-to-N-acetylaspartate concentration ratios in gray and white matter were estimated to be 0.13 and 0.28 by difference editing (95% confidence intervals 0.07-0.19 and 0.22-0.34), respectively, assuming identical relaxation effects between the metabolites.

Original languageEnglish (US)
Pages (from-to)1247-1251
Number of pages5
JournalMagnetic resonance in medicine
Issue number5
StatePublished - Nov 2010


  • 7 T
  • Difference editing
  • Gray matter
  • Human frontal brain
  • NAA
  • NAAG
  • White matter

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging


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