title: Proton T2 measurement and quantification of lactate in brain tumors by MRS at 3 Tesla in vivo.
abstract: OBJECTIVE
  To evaluate the T2 relaxation time of lactate (Lac) in brain tumors and the correlation of the T2 and concentration with tumor grades.
  
  
  METHODS
  Eight pairs of the subecho time sets of point-resolved spectroscopy were selected between 58 and 268 ms, with numerical and phantom analyses, for Lac T2 measurement. In vivo spectra were acquired from 24 subjects with gliomas (13 low grade and 11 high grade) and analyzed with LCModel using numerically-calculated basis spectra. The metabolite T2 relaxation time was obtained from monoexponential fitting of the multi-echo time (TE) signal estimates versus TE. The metabolite concentration was estimated from the zero-TE extrapolation of the T2 fits.
  
  
  RESULTS
  The Lac T2 was estimated to be approximately 240 ms, without a significant difference between low and high grade tumors. The Lac concentration was estimated to be 4.1 ± 3.4 and 7.0 ± 4.7 mM for low and high grades respectively, but the difference was not significant.
  
  
  CONCLUSIONS
  The Lac T2 was similar among gliomas regardless of their tumor grades. This suggests that the T2 value from this study may be applicable to obtain the T2 relaxation-free estimates of Lac in a subset of brain tumors.
authors.affiliation: Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
authors.forename: Akshay
authors.initials: A
authors.lastname: Madan
authors.affiliation: Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA.|Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
authors.forename: Sandeep K
authors.initials: SK
authors.lastname: Ganji
authors.affiliation: Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA.|Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
authors.forename: Zhongxu
authors.initials: Z
authors.lastname: An
authors.affiliation: Harold C. Simmons Cancer Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA.|Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
authors.forename: Kevin S
authors.initials: KS
authors.lastname: Choe
authors.affiliation: Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA.|Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
authors.forename: Marco C
authors.initials: MC
authors.lastname: Pinho
authors.affiliation: Harold C. Simmons Cancer Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA.|Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA.|Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, Texas, USA.|Annette Strauss Center for Neuro-Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Bachoo
authors.affiliation: Harold C. Simmons Cancer Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA.|Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA.|Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, Texas, USA.|Annette Strauss Center for Neuro-Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Maher
authors.affiliation: Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA.|Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA.|Harold C. Simmons Cancer Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
authors.forename: Changho
authors.initials: C
authors.lastname: Choi
mesh_terms: D000328:Adult; D000368:Aged; D016477:Artifacts; D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D001923:Brain Chemistry; D001932:Brain Neoplasms / Q000378:metabolism*; D002794:Choline / Q000378:metabolism; D003401:Creatine / Q000378:metabolism; D005260:Female; D005910:Glioma / Q000378:metabolism*; D006801:Humans; D019344:Lactic Acid / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D019047:Phantoms, Imaging; D066244:Proton Magnetic Resonance Spectroscopy / Q000379:methods*
chemical_list: D001224:Aspartic Acid; D019344:Lactic Acid; C000179:N-acetylaspartate; D003401:Creatine; D002794:Choline
keywords: 1H MRS; 3T; PRESS (point-resolved spectroscopy); T2; brain tumors; glioma; lactate