title: In vivo proton magnetic resonance spectroscopic imaging of the healthy human brain at 9.4 T: initial experience.
abstract: OBJECTIVE
  In this study, the feasibility of in vivo proton magnetic resonance spectroscopic imaging ((1)H MRSI) of the healthy human brain at a field strength of 9.4 T, using conventional acquisition techniques, is examined and the initial experience is summarized.
  
  
  METHODS
  MRSI measurements were performed on a 9.4 T MR scanner (Siemens, Erlangen, Germany) equipped with head-only gradient insert (AC84, Siemens) and custom-developed, 8-channel transmit/24-channel receive, and 16-channel transmit/31-channel receive coils. Spectra were acquired from the superior part of the human brain with a modified STEAM sequence. Spectral quantification was done with LCModel software.
  
  
  RESULTS
  Reasonable quality and signal-to-noise ratio of the acquired spectra allowed reliable quantification of 12 metabolites (Cramer-Rao lower bounds < 20 %), some of which may be difficult to quantify at field strengths below 7 T due to overlapping resonances or low concentrations.
  
  
  CONCLUSIONS
  While further developments are necessary to minimize chemical shift displacement and homogeneity of the transmit field, it is demonstrated that in vivo (1)H MRSI at a field strength of 9.4 T is possible. However, further studies applying up-to-date techniques to overcome high-field specific problems are needed in order to assess the potential gain in sensitivity that may be offered by MRSI at 9.4 T.
authors.affiliation: Biomedical Magnetic Resonance, University Hospital Tuebingen, Hoppe-Seyler-Str. 3, 72076, Tübingen, Germany, grzegorz.chadzynski@med.uni-tuebingen.de.
authors.forename: Grzegorz L
authors.initials: GL
authors.lastname: Chadzynski
authors.forename: Rolf
authors.initials: R
authors.lastname: Pohmann
authors.forename: Gunamony
authors.initials: G
authors.lastname: Shajan
authors.forename: Rupert
authors.initials: R
authors.lastname: Kolb
authors.forename: Sotirios
authors.initials: S
authors.lastname: Bisdas
authors.forename: Uwe
authors.initials: U
authors.lastname: Klose
authors.forename: Klaus
authors.initials: K
authors.lastname: Scheffler
mesh_terms: D000328:Adult; D001921:Brain / Q000033:anatomy & histology*; D001923:Brain Chemistry; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D057054:Molecular Imaging / Q000379:methods*; D010865:Pilot Projects; D066244:Proton Magnetic Resonance Spectroscopy / Q000379:methods*; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity