Magnetization transfer attenuation of creatine resonances in localized proton MRS of human brain in vivo

✍ Scribed by Gunther Helms; Jens Frahm

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 61 KB
• Volume: 12
• Category: Article
• ISSN: 0952-3480
• DOI: 10.1002/(sici)1099-1492(199912)12:8<490::aid-nbm593>3.0.co;2-1

✦ Synopsis

To assess putative magnetization transfer effects on the proton resonances of cerebral metabolites in human brain, we performed quantitative proton magnetic resonance spectroscopy (2.0 T, STEAM, TR/TE/TM = 6000/40/10 ms, LCModel data evaluation) of white matter (7.68 mL, 10 healthy young subjects) in the absence and presence of fast repetitive off-resonance irradiation (2.1 kHz from the water resonance) using a train of 100 Gaussian-shaped RF pulses (12.8 ms duration, 120 Hz nominal bandwidth, 40 ms repetition period, 1080 degrees nominal flip angle). A comparison of pertinent metabolite concentrations revealed a magnetization transfer attenuation factor of the methyl and methylene resonances of creatine and phosphocreatine of 0.87 +/- 0.05 (p < 0.01). No attenuation was observed for the resonances of N-acetylaspartate and N-acetylaspartylglutamate, glutamate and glutamine, choline-containing compounds, and myo-inositol. The finding for total creatine is in excellent agreement with data reported for rat brain. The results are consistent with the hypothesis of a chemical exchange of mobile creatine or phosphocreatine molecules with a small immobilized or 'bound' pool.