title: Two-site reproducibility of cerebellar and brainstem neurochemical profiles with short-echo, single-voxel MRS at 3T.
abstract: OBJECTIVE
  To determine whether neurochemical concentrations obtained at two MRI sites using clinical 3T scanners can be pooled when a highly optimized, nonvendor short-echo, single-voxel proton MRS pulse sequence is used in conjunction with identical calibration and quantification procedures.
  
  
  METHODS
  A modified semi-LASER sequence (TE = 28 ms) was used to acquire spectra from two brain regions (cerebellar vermis and pons) on two Siemens 3T scanners using the same B0 and B1 calibration protocols from two different cohorts of healthy volunteers (N = 24-33 per site) matched for age and body mass index. Spectra were quantified with LCModel using water scaling.
  
  
  RESULTS
  The spectral quality was very consistent between the two sites and allowed reliable quantification of at least 13 metabolites in the vermis and pons compared with 3-5 metabolites in prior multisite magnetic resonance spectroscopy trials using vendor-provided sequences. The neurochemical profiles were nearly identical at the two sites and showed the feasibility to detect interindividual differences in the healthy brain.
  
  
  CONCLUSIONS
  Highly reproducible neurochemical profiles can be obtained on different clinical 3T scanners at different sites, provided that the same, optimized acquisition and analysis techniques are used. This will allow pooling of multisite data in clinical studies, which is particularly critical for rare neurological diseases.
authors.affiliation: Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, Minnesota, USA.
authors.forename: Dinesh K
authors.initials: DK
authors.lastname: Deelchand
authors.forename: Isaac M
authors.initials: IM
authors.lastname: Adanyeguh
authors.forename: Uzay E
authors.initials: UE
authors.lastname: Emir
authors.forename: Tra-My
authors.initials: TM
authors.lastname: Nguyen
authors.forename: Romain
authors.initials: R
authors.lastname: Valabregue
authors.forename: Pierre-Gilles
authors.initials: PG
authors.lastname: Henry
authors.forename: Fanny
authors.initials: F
authors.lastname: Mochel
authors.forename: Gülin
authors.initials: G
authors.lastname: Öz
mesh_terms: D000328:Adult; D000368:Aged; D065814:Cerebellar Vermis / Q000502:physiology*; D004734:Energy Metabolism / Q000502:physiology*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011149:Pons / Q000502:physiology*; D066244:Proton Magnetic Resonance Spectroscopy / Q000379:methods*; D012016:Reference Values; D012680:Sensitivity and Specificity
keywords: 3 Tesla; multi-site; reproducibility; spectroscopy