title: Detection of 2-hydroxyglutarate in brain tumors by triple-refocusing MR spectroscopy at 3T in vivo.
abstract: To test the efficacy of triple-refocusing MR spectroscopy (MRS) for improved detection of 2-hydroxyglutarate (2HG) in brain tumors at 3T in vivo.
  
  
  
  The triple-refocusing sequence parameters were tailored at 3T, with density-matrix simulations and phantom validation, for enhancing the 2HG 2.25-ppm signal selectivity with respect to the adjacent resonances of glutamate (Glu), glutamine (Gln), and gamma-aminobutyric acid (GABA). In vivo MRS data were acquired from 15 glioma patients and analyzed with LCModel using calculated basis spectra. Metabolites were quantified with reference to water.
  
  
  
  A triple-refocusing sequence (echo time = 137 ms) was obtained for 2HG detection. The 2HG 2.25-ppm signal was large and narrow while the Glu and Gln signals between 2.2 and 2.3 ppm were minimal. The optimized triple refocusing offered improved separation of 2HG from Glu, Gln and GABA when compared with published MRS methods. 2HG was detected in all 15 patients, the estimated 2HG concentrations ranging from 2.4 to 15.0 mM, with Cramer-Rao lower bounds of 2%-11%. The 2HG estimates did not show significant correlation with total choline.
  
  
  
  The optimized triple refocusing provides excellent 2HG signal discrimination from adjacent resonances and may confer reliable in vivo measurement of 2HG at relatively low concentrations. Magn Reson Med 78:40-48, 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: Zhongxu
authors.identifier: 0000-0003-3759-5645
authors.initials: Z
authors.lastname: An
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: Vivek
authors.initials: V
authors.lastname: Tiwari
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: 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: Toral
authors.initials: T
authors.lastname: Patel
authors.affiliation: Department of Neurological Surgery, University of Texas Southwestern Medical Center, Dallas, Texas, USA.|Department of Otolaryngology, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
authors.forename: Samuel
authors.initials: S
authors.lastname: Barnett
authors.affiliation: 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.|Harold C. Simmons Cancer Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
authors.forename: Edward
authors.initials: E
authors.lastname: Pan
authors.affiliation: Department of Neurological Surgery, University of Texas Southwestern Medical Center, Dallas, Texas, USA.|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: Bruce E
authors.initials: BE
authors.lastname: Mickey
authors.affiliation: Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, Texas, USA.|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 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.|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; D000465:Algorithms; D014408:Biomarkers, Tumor / Q000032:analysis*; D001932:Brain Neoplasms / Q000737:chemistry* / Q000175:diagnosis* / Q000473:pathology; D005260:Female; D005977:Glutarates / Q000032:analysis*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D008875:Middle Aged; 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; 3T; glioma; human brain tumor; isocitrate dehydrogenase; triple refocusing