title: Oxidation of [U-13C]glucose in the human brain at 7T under steady state conditions.
abstract: OBJECTIVE
  Disorders of brain energy metabolism and neurotransmitter recycling have been implicated in multiple neurological conditions.13C magnetic resonance spectroscopy (13C MRS) during intravenous administration of13C-labeled compounds has been used to measure turnover rates of brain metabolites. This approach, however, requires prolonged infusion inside the magnet. Proton decoupling is typically required but may be difficult to implement with standard equipment. We examined an alternative approach to monitor glucose metabolism in the human brain.
  
  
  METHODS
  13C-enriched glucose was infused in healthy subjects outside the magnet to a steady-state level of13C enrichment. Subsequently, the subjects were scanned at 7T for 60 min without1H decoupling. Metabolic modeling was used to calculate anaplerosis.
  
  
  RESULTS
  Biomarkers of energy metabolism and anaplerosis were detected. The glutamate C5 doublet provided information about glucose-derived acetyl-coenzyme A flux into the tricarboxylic acid (TCA) cycle via pyruvate dehydrogenase, and the bicarbonate signal reflected overall TCA cycle activity. The glutamate C1/C5 ratio is sensitive to anaplerosis.
  
  
  CONCLUSIONS
  Brain13C MRS at 7T provides information about glucose oxidation and anaplerosis without the need of prolonged13C infusions inside the scanner and without technical challenges of1H decoupling, making it a feasible approach for clinical research. Magn Reson Med 78:2065-2071, 2017. © 2017 International Society for Magnetic Resonance in Medicine.
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: Sergey
authors.initials: S
authors.lastname: Cheshkov
authors.affiliation: Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA.|Philips Medical Systems, Cleveland, Ohio, USA.
authors.forename: Ivan E
authors.initials: IE
authors.lastname: Dimitrov
authors.affiliation: Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
authors.forename: Vikram
authors.initials: V
authors.lastname: Jakkamsetti
authors.affiliation: Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
authors.forename: Levi
authors.initials: L
authors.lastname: Good
authors.affiliation: Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
authors.forename: Dorothy
authors.initials: D
authors.lastname: Kelly
authors.affiliation: Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
authors.forename: Karthik
authors.initials: K
authors.lastname: Rajasekaran
authors.affiliation: Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
authors.forename: Ralph J
authors.initials: RJ
authors.lastname: DeBerardinis
authors.affiliation: Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, Texas, USA.|Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas, USA.|Department of Physiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
authors.forename: Juan M
authors.initials: JM
authors.lastname: Pascual
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.|Department of Chemistry, University of Texas at Dallas, Richardson, Texas, USA.
authors.forename: A Dean
authors.initials: AD
authors.lastname: Sherry
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.|Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA.|VA North Texas Health Care System, Dallas, Texas, USA.
authors.forename: Craig R
authors.initials: CR
authors.lastname: Malloy
mesh_terms: D001921:Brain / Q000000981:diagnostic imaging* / Q000378:metabolism; D002247:Carbon Isotopes / Q000737:chemistry*; D002952:Citric Acid Cycle; D005240:Feasibility Studies; D005947:Glucose / Q000737:chemistry*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007658:Ketone Oxidoreductases / Q000378:metabolism; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D008280:Magnetics; D008297:Male; D018377:Neurotransmitter Agents; D010100:Oxygen / Q000737:chemistry*; D011522:Protons
chemical_list: D002247:Carbon Isotopes; D018377:Neurotransmitter Agents; D011522:Protons; D007658:Ketone Oxidoreductases; C053164:pyruvate dehydrogenase (NADP+); D005947:Glucose; D010100:Oxygen
keywords: 13C MRS; 13C bicarbonate; 7 Tesla; TCA cycle; brain energy metabolism