title: Efficient31P band inversion transfer approach for measuring creatine kinase activity, ATP synthesis, and molecular dynamics in the human brain at 7 T.
abstract: To develop an efficient31P magnetic resonance spectroscopy (MRS) method for measuring creatine kinase (CK) activity, adenosine triphosphate (ATP) synthesis, and motion dynamics in the human brain at 7 Tesla (T).
  
  
  
  Three band inversion modules differing in center frequency were used to induce magnetization transfer (MT) effect in three exchange pathways: (i) CK-mediated reaction PCr → γ-ATP; (ii) de novo ATP synthesis Pi → γ-ATP; and (iii) ATP intramolecular31P-31P cross-relaxation γ-(α-) ↔ β-ATP. The resultant MT data were analyzed using a 5-pool model in the format of magnetization matrix according to Bloch-McConnell-Solomon formalism.
  
  
  
  With a repetition time (TR) of 4 s, the scan time for each module was approximately 8 min. The rate constants were kPCr → γATP0.38 ± 0.02 s-1, kPi → γATP0.19 ± 0.02 s-1, and σγ(α) ↔ βATP0.19 ± 0.04 s-1, corresponding to ATP rotation correlation time τc(0.8 ± 0.2) ·10-7s. The T1relaxation times were Pi 7.26 ± 1.76 s, PCr 5.99 ± 0.58 s, γ-ATP 0.98 ± 0.07 s, α-ATP 0.95 ± 0.04 s, and β-ATP 0.68 ± 0.03 s.
  
  
  
  Short-TR band inversion modules provide a time-efficient way of measuring brain ATP metabolism and could be useful in studying metabolic disorders in brain diseases. Magn Reson Med 78:1657-1666, 2017. © 2016 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: Jimin
authors.initials: J
authors.lastname: Ren
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: D000255:Adenosine Triphosphate / Q000032:analysis* / Q000378:metabolism; D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging* / Q000378:metabolism*; D001923:Brain Chemistry; D003198:Computer Simulation; D003402:Creatine Kinase / Q000032:analysis* / Q000378:metabolism; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010759:Phosphorus Isotopes / Q000032:analysis* / Q000378:metabolism; D015203:Reproducibility of Results
chemical_list: D010759:Phosphorus Isotopes; D000255:Adenosine Triphosphate; D003402:Creatine Kinase
keywords: 31P MRS; ATP; human brain; inversion transfer; magnetization transfer; relaxation time