title: Single-shot, three-dimensional "non-echo" localization method for in vivo NMR spectroscopy.
abstract: Metabolite signals with short T(1) or T(2) are difficult to localize with full sensitivity. This limitation was overcome with the development and implementation of a single-shot, complete three-dimensional "non-echo" localization method with reduced sensitivity to spatial B(1) variation, which is suitable for measuring signals with very short T(1) or T(2), e.g., the (13)C NMR signals of glycogen. The proposed method is based on a T(1)-optimized outer volume suppression scheme using pulses of the hyperbolic secant type applied at different power levels, which is robust over a fivefold range of T(1). Strong lipid, muscle glycogen, and glucose signals originating outside the rat brain were suppressed. Signals of glycogen, aspartate, glutathione, GABA C4, N-acetyl aspartate as well as the C3 and C4 signals of glutamate and glutamine with resolved homonuclear (13)C-(13)C coupling were fully resolved in vivo at 9.4 Tesla using higher-order shimming. The method can be extended to other nuclei and to localized MRS of humans.
authors.affiliation: Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota Medical School, Minneapolis, Minnesota, USA.
authors.forename: I Y
authors.initials: IY
authors.lastname: Choi
authors.forename: I
authors.initials: I
authors.lastname: Tkác
authors.forename: R
authors.initials: R
authors.lastname: Gruetter
mesh_terms: D000085:Acetates / Q000032:analysis; D000818:Animals; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000032:analysis; D001923:Brain Chemistry; D002138:Calibration; D002247:Carbon Isotopes / Q000032:analysis; D005069:Evaluation Studies as Topic; D005561:Formates; D005947:Glucose / Q000032:analysis; D018698:Glutamic Acid / Q000032:analysis; D005973:Glutamine / Q000032:analysis; D006003:Glycogen / Q000032:analysis; D007294:Inositol / Q000032:analysis; D008055:Lipids / Q000032:analysis; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D018482:Muscle, Skeletal / Q000737:chemistry; D010125:Ostreidae; D019047:Phantoms, Imaging; D011522:Protons; D011846:Radio Waves; D051381:Rats; D012680:Sensitivity and Specificity; D005680:gamma-Aminobutyric Acid / Q000032:analysis
chemical_list: D000085:Acetates; D002247:Carbon Isotopes; D005561:Formates; D008055:Lipids; D011522:Protons; D005973:Glutamine; C030544:formic acid; D001224:Aspartic Acid; D018698:Glutamic Acid; D007294:Inositol; D005680:gamma-Aminobutyric Acid; D006003:Glycogen; C000179:N-acetylaspartate; D005947:Glucose