title: Measuring N-acetylaspartate synthesis in vivo using proton magnetic resonance spectroscopy.
abstract: N-Acetylaspartate (NAA) is an important marker of neuronal function and viability that can be measured using magnetic resonance spectroscopy (MRS). In this paper, we proposed a method to measure NAA synthesis using proton MRS with infusion of uniformly (13)C-labeled glucose, and demonstrated its feasibility in an in vivo study of the rat brain. The rate of (13)C-label incorporation into the acetyl group of NAA was measured using a localized, long echo-time proton MRS method. Signals from the (13)C satellites of the main NAA methyl protons at 2.02 ppm were continuously monitored for 10h. Quantification of the data based on a linear kinetic model showed that NAA synthesis rate in isoflurane-anesthetized rats was 0.19+/-0.02 micromol/g/h (mean+/-standard deviation, n=12).
authors.affiliation: Molecular Imaging Branch, National Institute of Mental Health, 9000 Rockville Pike, Bethesda, MD 20892-1527, USA. suxu@intra.nimh.nih.gov
authors.forename: Su
authors.initials: S
authors.lastname: Xu
authors.forename: Jehoon
authors.initials: J
authors.lastname: Yang
authors.forename: Jun
authors.initials: J
authors.lastname: Shen
mesh_terms: D000818:Animals; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000378:metabolism; D002247:Carbon Isotopes / Q000378:metabolism; D005947:Glucose / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D011522:Protons; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D002247:Carbon Isotopes; D011522:Protons; D001224:Aspartic Acid; C000179:N-acetylaspartate; D005947:Glucose