title: Spatial variability and reproducibility of GABA-edited MEGA-LASER 3D-MRSI in the brain at 3 T.
abstract: The reproducibility of gamma-aminobutyric acid (GABA) quantification results, obtained with MRSI, was determined on a 3 T MR scanner in healthy adults. In this study, a spiral-encoded, GABA-edited, MEGA-LASER MRSI sequence with real-time motion-scanner-instability corrections was applied for robust 3D mapping of neurotransmitters in the brain. In particular, the GABA+(i.e. GABA plus macromolecule contamination) and Glx (i.e. glutamate plus glutamine contamination) signal was measured. This sequence enables 3D-MRSI with about 3 cm3nominal resolution in about 20 min. Since reliable quantification of GABA is challenging, the spatial distribution of the inter-subject and intra-subject variability of GABA+and Glx levels was studied via test-retest assessment in 14 healthy volunteers (seven men-seven women). For both inter-subject and intra-subject repeated measurement sessions a low coefficient of variation (CV) and a high intraclass correlation coefficient (ICC) were found for GABA+and Glx ratios across all evaluated voxels (intra-/inter-subject: GABA+ratios, CV ~ 8%-ICC > 0.75; Glx ratios, CV ~ 6%-ICC > 0.70). The same was found in selected brain regions for Glx ratios versus GABA+ratios (CV varied from about 5% versus about 8% in occipital and parietal regions, to about 8% versus about 10% in the frontal area, thalamus, and basal ganglia). These results provide evidence that 3D mapping of GABA+and Glx using the described methodology provides high reproducibility for application in clinical and neuroscientific studies.
authors.affiliation: Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Biomedical Center Martin, Division of Neurosciences, Martin, Slovakia.
authors.forename: Petra
authors.initials: P
authors.lastname: Hnilicová
authors.affiliation: Christian Doppler Laboratory for Clinical Molecular MR Imaging, Vienna, Austria.
authors.forename: Michal
authors.initials: M
authors.lastname: Považan
authors.affiliation: High Field MR Center, Medical University of Vienna, Department of Biomedical Imaging and Image-guided Therapy, Vienna, Austria.
authors.forename: Bernhard
authors.identifier: 0000-0001-9542-3855
authors.initials: B
authors.lastname: Strasser
authors.affiliation: Massachusetts General Hospital, Harvard Medical School, Martinos Center for Biomedical Imaging, Boston, Massachusetts, USA.
authors.forename: Ovidiu C
authors.initials: OC
authors.lastname: Andronesi
authors.affiliation: High Field MR Center, Medical University of Vienna, Department of Biomedical Imaging and Image-guided Therapy, Vienna, Austria.
authors.forename: Martin
authors.initials: M
authors.lastname: Gajdošík
authors.affiliation: Purdue University, School of Health Sciences, West Lafayette, IN, USA, Indiana University School of Medicine, Department of Radiology and Imaging Sciences, Indianapolis, Indiana, USA.
authors.forename: Ulrike
authors.initials: U
authors.lastname: Dydak
authors.affiliation: Institute of Experimental Endocrinology, Biomedical Research Center, Slovak Academy of Sciences, Obesity Section, Diabetes and Metabolic Disease Laboratory, Bratislava, Slovakia.
authors.forename: Jozef
authors.initials: J
authors.lastname: Ukropec
authors.affiliation: Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Department of Medical Biochemistry, Martin, Slovakia.
authors.forename: Dušan
authors.initials: D
authors.lastname: Dobrota
authors.affiliation: Christian Doppler Laboratory for Clinical Molecular MR Imaging, Vienna, Austria.
authors.forename: Siegfried
authors.initials: S
authors.lastname: Trattnig
authors.affiliation: High Field MR Center, Medical University of Vienna, Department of Biomedical Imaging and Image-guided Therapy, Vienna, Austria. wolfgang.bogner@meduniwien.ac.at.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Bogner
mesh_terms: D000328:Adult; D000465:Algorithms; D016477:Artifacts; D001921:Brain / Q000033:anatomy & histology / Q000378:metabolism*; D003199:Computer Systems; D005260:Female; D006801:Humans; 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; D012815:Signal Processing, Computer-Assisted; D062211:Spatio-Temporal Analysis; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
chemical_list: D018377:Neurotransmitter Agents; D005680:gamma-Aminobutyric Acid
keywords: MEGA editing; MRS and MRSI methods; acquisition methods; neurotransmitters; normal brain; reproducibility