title: Reproducibility and reliability of short-TE whole-brain MR spectroscopic imaging of human brain at 3T.
abstract: OBJECTIVE
  A feasibility study of an echo-planar spectroscopic imaging (EPSI) using a short echo time (TE) that trades off sensitivity, compared with other short-TE methods, to achieve whole brain coverage using inversion recovery and spatial oversampling to control lipid bleeding.
  
  
  METHODS
  Twenty subjects were scanned to examine intersubject variance. One subject was scanned five times to examine intrasubject reproducibility. Data were analyzed to determine coefficients of variance (COV) and intraclass correlation coefficient (ICC) for N-acetylaspartate (NAA), total creatine (tCr), total choline (tCho), glutamine/glutamate (Glx), and myo-inositol (mI). Regional metabolite concentrations were derived by using multi-voxel analysis based on lobar-level anatomic regions.
  
  
  RESULTS
  For whole-brain mean values, the intrasubject COVs were 14%, 15%, and 20% for NAA, tCr, and tCho, respectively, and 31% for Glx and mI. The intersubject COVs were up to 6% higher. For regional distributions, the intrasubject COVs were ≤ 5% for NAA, tCr, and tCho; ≤ 9% for Glx; and ≤15% for mI, with about 6% higher intersubject COVs. The ICCs of 5 metabolites were ≥ 0.7, indicating the reliability of the measurements.
  
  
  CONCLUSIONS
  The present EPSI method enables estimation of the whole-brain metabolite distributions, including Glx and mI with small voxel size, and a reasonable scan time and reproducibility.
authors.affiliation: Institute of Diagnostic and Interventional Neuroradiology, Hannover Medical School, Hannover, Germany.
authors.forename: Xiao-Qi
authors.initials: XQ
authors.lastname: Ding
authors.forename: Andrew A
authors.initials: AA
authors.lastname: Maudsley
authors.forename: Mohammad
authors.initials: M
authors.lastname: Sabati
authors.forename: Sulaiman
authors.initials: S
authors.lastname: Sheriff
authors.forename: Paulo R
authors.initials: PR
authors.lastname: Dellani
authors.forename: Heinrich
authors.initials: H
authors.lastname: Lanfermann
mesh_terms: D000328:Adult; D000465:Algorithms; D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D001921:Brain / Q000033:anatomy & histology / Q000378:metabolism*; D002794:Choline / Q000378:metabolism; D003401:Creatine / Q000378:metabolism; D005260:Female; D018698:Glutamic Acid / Q000378:metabolism; D005973:Glutamine / Q000378:metabolism; D006801:Humans; D007294:Inositol / Q000378:metabolism; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008954:Models, Biological; D057054:Molecular Imaging / Q000379:methods*; D066244:Proton Magnetic Resonance Spectroscopy / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014018:Tissue Distribution
chemical_list: D005973:Glutamine; D001224:Aspartic Acid; D018698:Glutamic Acid; D007294:Inositol; C000179:N-acetylaspartate; D003401:Creatine; D002794:Choline
keywords: glutamate; glutamine; myo-inositol; short TE MRSI; short acquisition time; whole-brain MRSI