title: Asymmetry and gender effect in functionally lateralized cortical regions: a proton MRS imaging study.
abstract: OBJECTIVE
  to compare metabolite concentrations and ratios in gray matter regions known for their anatomical/functional asymmetry and evaluate gender effect.
  
  
  METHODS
  Proton MRS imaging was performed at 1.5 T with TR/TE 2300/280 msec in 20 healthy right-handed subjects (mean age 29.6 +/- 5.3 years, 10 men). Concentrations of N-acetyl aspartate (NAA), choline (Cho), and creatine (Cr), and the peak area ratios NAA/Cho, NAA/Cr, and Cho/Cr were evaluated in hippocampal and parahippocampal gyri, thalamus, insula, Broca's and Wernicke's areas (and corresponding contralateral areas), primary and secondary visual areas, temporal, inferior parietal, cingulate, supplemental motor, dorsolateral prefrontal, and sensorimotor areas. Linear mixed-effects regression models were used for statistical analyses.
  
  
  RESULTS
  NAA concentration and NAA/Cho were higher in the left thalamus by 21.9% and 20%, respectively (both P < 0.001). NAA concentration was 13% higher in the region contralateral to Wernicke's area (P < 0.02). No gender differences were found.
  
  
  CONCLUSIONS
  Metabolite concentrations and ratios were symmetric and gender independent in most brain regions, however small hemispheric side differences in the thalamus and in Wernicke's area were found.
authors.affiliation: The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University, School of Medicine, Baltimore, Maryland 21205, USA.
authors.forename: Lidia M
authors.initials: LM
authors.lastname: Nagae-Poetscher
authors.forename: David
authors.initials: D
authors.lastname: Bonekamp
authors.forename: Peter B
authors.initials: PB
authors.lastname: Barker
authors.forename: Larry J
authors.initials: LJ
authors.lastname: Brant
authors.forename: Walter E
authors.initials: WE
authors.lastname: Kaufmann
authors.forename: Alena
authors.initials: A
authors.lastname: Horská
mesh_terms: D000328:Adult; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000378:metabolism; D001921:Brain / Q000378:metabolism*; D002794:Choline / Q000378:metabolism; D003404:Creatinine / Q000378:metabolism; D005260:Female; D006801:Humans; D016014:Linear Models; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D011522:Protons; D012737:Sex Factors
chemical_list: D011522:Protons; D001224:Aspartic Acid; C000179:N-acetylaspartate; D003404:Creatinine; D002794:Choline