title: In vivo estimation of gamma-aminobutyric acid levels in the neonatal brain.
abstract: Gamma-aminobutyric acid (GABA) is the major inhibitory neurotransmitter in the brain, and plays a key role in brain development. However, the in vivo levels of brain GABA in early life are unknown. Using edited MRS, in vivo GABA can be detected as GABA+ signal with contamination of macromolecule signals. GABA+ is evaluated as the peak ratio of GABA+/reference compound, for which creatine (Cr) or water is typically used. However, the concentrations and T1and T2relaxation times of these references change during development. Thus, the peak ratio comparison between neonates and children may be inaccurate. The aim of this study was to measure in vivo neonatal brain GABA+ levels, and to investigate the dependency of GABA levels on brain region and age. The basal ganglia and cerebellum of 38 neonates and 12 children were measured using GABA-edited MRS. Two different approaches were used to obtain GABA+ levels: (i) multiplying the GABA/water ratio by the water concentration; and (ii) multiplying the GABA+/Cr by the Cr concentration. Neonates exhibited significantly lower GABA+ levels compared with children in both regions, regardless of the approach employed, consistent with previous ex vivo data. A similar finding of lower GABA+/water and GABA+/Cr in neonates compared with children was observed, except for GABA+/Cr in the cerebellum. This contrasting finding resulted from significantly lower Cr concentrations in the neonate cerebellum, which were approximately 52% of those of children. In conclusion, care should be taken to consider Cr concentrations when comparing GABA+/Cr levels between different-aged subjects.
authors.affiliation: Department of Molecular Imaging and Theranostics, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan.|Research Center for Child Mental Development, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, 260-8670, Japan.|Department of Radiology, Kanagawa Children's Medical Center, 2-138-4 Mutsukawa, Minami-ku, Yokohama, 232-8555, Japan.
authors.forename: Moyoko
authors.initials: M
authors.lastname: Tomiyasu
authors.affiliation: Research Center for Child Mental Development, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, 260-8670, Japan.|Department of Radiology, Kanagawa Children's Medical Center, 2-138-4 Mutsukawa, Minami-ku, Yokohama, 232-8555, Japan.
authors.forename: Noriko
authors.initials: N
authors.lastname: Aida
authors.affiliation: Department of Neonatology, Kanagawa Children's Medical Center, 2-138-4 Mutsukawa, Minami-ku, Yokohama, 232-8555, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Shibasaki
authors.affiliation: Medical MR Center, Meiji University of Integrative Medicine, Hiyoshi, Nantan, Kyoto, 629-0392, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Umeda
authors.affiliation: Imaging and Therapy System Division, Siemens Japan, 1-11-1 Osaki, Shinagawa, Tokyo, 141-8644, Japan.
authors.forename: Katsutoshi
authors.initials: K
authors.lastname: Murata
authors.affiliation: Biomedical Imaging Technology Center, Burlington, Massachusetts, USA.
authors.forename: Keith
authors.initials: K
authors.lastname: Heberlein
authors.affiliation: Siemens Medical Solutions USA, 209 Gregson Drive, Cary, North Carolina, 27511, USA.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Brown
authors.affiliation: Research Center for Child Mental Development, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, 260-8670, Japan.
authors.forename: Eiji
authors.initials: E
authors.lastname: Shimizu
authors.affiliation: Department of Molecular Imaging and Theranostics, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Tsuji
authors.affiliation: Department of Molecular Imaging and Theranostics, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan.|Department of Radiology, Kanagawa Children's Medical Center, 2-138-4 Mutsukawa, Minami-ku, Yokohama, 232-8555, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Obata
mesh_terms: D000465:Algorithms; D016477:Artifacts; D001921:Brain / Q000378:metabolism*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007231:Infant, Newborn; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D057054:Molecular Imaging / Q000379:methods*; D018377:Neurotransmitter Agents / Q000378:metabolism; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014018:Tissue Distribution; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
chemical_list: D018377:Neurotransmitter Agents; D005680:gamma-Aminobutyric Acid
keywords: MEGA-PRESS; gamma-aminobutyric acid (GABA); human study; neonates; normal brain; spectroscopic quantitation