title: In vivo measurement of brain metabolites using two-dimensional double-quantum MR spectroscopy--exploration of GABA levels in a ketogenic diet.
abstract: A localized proton 2D double-quantum (DQ) spin-echo spectroscopy technique was implemented on 1.5 T clinical MRI scanners for the detection of gamma-aminobutyrate (GABA) in the brain. The 2D approach facilitates separation of peaks overlapping with GABA in 1D DQ-filtered (DQF) spectra. This technique was applied to four normal adult volunteers and four children with intractable epilepsy. The coefficient of variation of the level of GABA and overlapping macromolecules at F2 = 3.0 ppm and F1 = 4.8 ppm was 0.08 in normal subjects. Three patients received 2D MRS scans before and after initiation of the ketogenic diet (KD): one patient showed a trend of decreasing GABA throughout the study, and two patients showed low initial GABA levels that increased over time. In addition to major metabolites and GABA, low-level metabolites (valine, leucine, and glutathione) were also identified in the 2D spectra.
authors.affiliation: Department of Radiology, Children's Hospital of Philadelphia, Philadelphia, PA, USA. zjwang@bcm.tmc.edu
authors.forename: Zhiyue J
authors.initials: ZJ
authors.lastname: Wang
authors.forename: Christina
authors.initials: C
authors.lastname: Bergqvist
authors.forename: Jill V
authors.initials: JV
authors.lastname: Hunter
authors.forename: Dongzhu
authors.initials: D
authors.lastname: Jin
authors.forename: Dah-Jyuu
authors.initials: DJ
authors.lastname: Wang
authors.forename: Suzanne
authors.initials: S
authors.lastname: Wehrli
authors.forename: Robert A
authors.initials: RA
authors.lastname: Zimmerman
mesh_terms: D000328:Adult; D001921:Brain / Q000378:metabolism*; D001931:Brain Mapping; D002648:Child; D002675:Child, Preschool; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007662:Ketosis / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D012016:Reference Values; D012640:Seizures / Q000178:diet therapy* / Q000378:metabolism; D005680:gamma-Aminobutyric Acid / Q000032:analysis / Q000378:metabolism*
chemical_list: D005680:gamma-Aminobutyric Acid