title: In vivo detection of 2-hydroxyglutarate in brain tumors by optimized point-resolved spectroscopy (PRESS) at 7T.
abstract: To test the efficacy of 7T MRS for in vivo detection of 2-hydroxyglutarate (2HG) in brain tumors.
  
  
  
  The subecho times of point-resolved spectroscopy (PRESS) were optimized at 7T with density-matrix simulations and phantom validation to improve the 2HG signal selectivity with respect to the neighboring resonances of γ-aminobutyric acid (GABA), glutamate (Glu), and glutamine (Gln). MRS data were acquired from 12 subjects with gliomas in vivo and analyzed with LCModel using calculated basis spectra. Metabolite levels were quantified using unsuppressed short echo time (TE) water as a reference.
  
  
  
  The PRESS TE was optimized as TE = 78 ms (TE1= 58 ms and TE2= 20 ms), at which the 2HG 2.25 ppm resonance appeared as a temporally maximum inverted narrow peak and the GABA, Glu, and Gln resonances between 2.2 and 2.5 ppm were all positive peaks. The PRESS TE = 78 ms method offered improved discrimination of 2HG from Glu, Gln, and GABA when compared with short-TE MRS. 2HG was detected in all patients enrolled in the study, the estimated 2HG concentrations ranging from 1.0 to 6.2 mM, with percentage standard deviation of 2%-7%.
  
  
  
  Data indicate that the optimized MRS provides good selectivity of 2HG from other metabolite signals and may confer reliable in vivo detection of 2HG at relatively low concentrations. Magn Reson Med 77:936-944, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
authors.affiliation: Advanced Imaging Research Center, 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.
authors.forename: Zhongxu
authors.initials: Z
authors.lastname: An
authors.affiliation: Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
authors.forename: Vivek
authors.initials: V
authors.lastname: Tiwari
authors.affiliation: Harold C. Simmons Cancer Center, 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: Sarah
authors.initials: S
authors.lastname: McNeil
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 Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, Texas, USA.|Department of Neurological Surgery, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
authors.forename: Edward
authors.initials: E
authors.lastname: Pan
authors.affiliation: Harold C. Simmons Cancer Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA.|Annette Strauss Center for Neuro-Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA.|Department of Neurological Surgery, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
authors.forename: Bruce E
authors.initials: BE
authors.lastname: Mickey
authors.affiliation: Harold C. Simmons Cancer Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA.|Annette Strauss Center for Neuro-Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA.|Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, Texas, USA.|Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Maher
authors.affiliation: Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA.|Harold C. Simmons Cancer Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA.|Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
authors.forename: Changho
authors.initials: C
authors.lastname: Choi
mesh_terms: D000465:Algorithms; D014408:Biomarkers, Tumor / Q000378:metabolism*; D001921:Brain / Q000378:metabolism / Q000473:pathology; D001932:Brain Neoplasms / Q000378:metabolism* / Q000473:pathology; D005977:Glutarates / Q000378:metabolism*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted
chemical_list: D014408:Biomarkers, Tumor; D005977:Glutarates; C019417:alpha-hydroxyglutarate
keywords: 1H MRS; 2-hydroxyglutarate (2HG); 7T, PRESS (point-resolved spectroscopy); IDH (isocitrate dehydrogenase); gliomas; human brain tumors