title: Investigating hyperoxic effects in the rat brain using quantitative susceptibility mapping based on MRI phase.
abstract: To test whether susceptibility imaging can detect microvenous oxygen saturation changes, induced by hyperoxia, in the rat brain.
  
  
  
  A three-dimensional gradient-echo with a flow compensation sequence was used to acquire T2*-weighted images of rat brains during hyperoxia and normoxia. Quantitative susceptibility mapping (QSM) and QSM-based microvenous oxygenation venography were computed from gradient-echo (GRE) phase images and compared between the two conditions. Pulse oxygen saturation (SpO2) in the cortex was examined and compared with venous oxygen saturation (SvO2) estimated by QSM. Oxygen saturation change calculated by a conventional Δ R2* map was also compared with the ΔSvO2estimated by QSM.
  
  
  
  Susceptibilities of five venous and tissue regions were quantified separately by QSM. Venous susceptibility was reduced by nearly 10%, with an SvO2shift of 10% during hyperoxia. A hyperoxic effect, confirmed by SpO2measurement, resulted in an SvO2increase in the cortex. The ΔSvO2between hyperoxia and normoxia was consistent with what was estimated by the Δ R2* map in five regions.
  
  
  
  These findings suggest that a quantitative susceptibility map is a promising technique for SvO2measurement. This method may be useful for quantitatively investigating oxygenation-dependent functional MRI studies. Magn Reson Med 77:592-602, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
authors.affiliation: Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei 106, Taiwan.|Molecular Imaging Center, National Taiwan University, Taipei 106, Taiwan.|Department of Electrical Engineering, National Taiwan University, Taipei 106, Taiwan.
authors.forename: Meng-Chi
authors.initials: MC
authors.lastname: Hsieh
authors.affiliation: Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, Miaoli County 350, Taiwan.
authors.forename: Li-Wei
authors.initials: LW
authors.lastname: Kuo
authors.affiliation: Department of Electrical Engineering, National Taiwan University, Taipei 106, Taiwan.
authors.forename: Yun-An
authors.initials: YA
authors.lastname: Huang
authors.affiliation: Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei 106, Taiwan.|Molecular Imaging Center, National Taiwan University, Taipei 106, Taiwan.|Department of Electrical Engineering, National Taiwan University, Taipei 106, Taiwan.
authors.forename: Jyh-Horng
authors.initials: JH
authors.lastname: Chen
mesh_terms: D000465:Algorithms; D000818:Animals; D001921:Brain / Q000000981:diagnostic imaging / Q000378:metabolism*; D002550:Cerebral Veins / Q000378:metabolism*; D018496:Hyperoxia / Q000000981:diagnostic imaging / Q000378:metabolism*; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D057054:Molecular Imaging / Q000379:methods; D010092:Oximetry / Q000379:methods*; D010100:Oxygen / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D010100:Oxygen
keywords: hyperoxia; magnetic resonance imaging (MRI); quantitative susceptibility mapping (QSM); rat brain; venous oxygen saturation (SvO2)