title: Parameterization of spectral baseline directly from short echo time full spectra in1H-MRS.
abstract: To investigate the feasibility of parameterizing macromolecule (MM) resonances directly from short echo time (TE) spectra rather than pre-acquired, T1-weighted, metabolite-nulled spectra in1H-MRS.
  
  
  
  Initial line parameters for metabolites and MMs were set for rat brain spectra acquired at 9.4 Tesla upon a priori knowledge. Then, MM line parameters were optimized over several steps with fixed metabolite line parameters. The proposed method was tested by estimating metabolite T1. The results were compared with those obtained with two existing methods. Furthermore, subject-specific, spin density-weighted, MM model spectra were generated according to the MM line parameters from the proposed method for metabolite quantification. The results were compared with those obtained with subject-specific, T1-weighted, metabolite-nulled spectra.
  
  
  
  The metabolite T1were largely in close agreement among the three methods. The spin density-weighted MM resonances from the proposed method were in good agreement with the T1-weighted, metabolite-nulled spectra except for the MM resonance at ∼3.2 ppm. The metabolite concentrations estimated by incorporating these two different spectral baselines were also in good agreement except for several metabolites with resonances at ∼3.2 ppm.
  
  
  
  The MM parameterization directly from short-TE spectra is feasible. Further development of the method may allow for better representation of spectral baseline with negligible T1-weighting. Magn Reson Med 78:836-847, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
authors: Department of Biomedical Sciences, Seoul National University, Seoul, Korea.
authors: Hyeong Hun
authors: HH
authors: Lee
authors: Department of Biomedical Sciences, Seoul National University, Seoul, Korea.|Department of Radiology, Seoul National University Hospital, Seoul, Korea.|Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, Suwon, Korea.
authors: Hyeonjin
authors: H
authors: Kim
mesh_terms: D000818:Animals; D001921:Brain / Q000000981:diagnostic imaging / Q000378:metabolism; D001923:Brain Chemistry; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D019047:Phantoms, Imaging; D011522:Protons; D051381:Rats
chemical_list: D011522:Protons
keywords: baseline parameterization; macromolecules; metabolite T1; metabolite quantification; proton magnetic resonance spectroscopy (1H-MRS); spectral baseline