title: Phosphodiester content measured in human liver by in vivo31P MR spectroscopy at 7 tesla.
abstract: OBJECTIVE
  Phosphorus (31P) metabolites are emerging liver disease biomarkers. Of particular interest are phosphomonoester and phosphodiester (PDE) "peaks" that comprise multiple overlapping resonances in31P spectra. This study investigates the effect of improved spectral resolution at 7 Tesla (T) on quantifying hepatic metabolites in cirrhosis.
  
  
  METHODS
  Five volunteers were scanned to determine metabolite T1s. Ten volunteers and 11 patients with liver cirrhosis were scanned at 7T. Liver spectra were acquired in 28 min using a 16-channel31P array and 3D chemical shift imaging. Concentrations were calculated using γ-adenosine-triphosphate (γ-ATP) = 2.65 mmol/L wet tissue.
  
  
  RESULTS
  T1means ± standard deviations: phosphatidylcholine 1.05 ± 0.28 s, nicotinamide-adenine-dinucleotide (NAD+) 2.0 ± 1.0 s, uridine-diphosphoglucose (UDPG) 3.3 ± 1.4 s. Concentrations in healthy volunteers: α-ATP 2.74 ± 0.11 mmol/L wet tissue, inorganic phosphate 2.23 ± 0.20 mmol/L wet tissue, glycerophosphocholine 2.34 ± 0.46 mmol/L wet tissue, glycerophosphoethanolamine 1.50 ± 0.28 mmol/L wet tissue, phosphocholine 1.06 ± 0.16 mmol/L wet tissue, phosphoethanolamine 0.77 ± 0.14 mmol/L wet tissue, NAD+2.37 ± 0.14 mmol/L wet tissue, UDPG 2.00 ± 0.22 mmol/L wet tissue, phosphatidylcholine 1.38 ± 0.31 mmol/L wet tissue. Inorganic phosphate and phosphatidylcholine concentrations were significantly lower in patients; glycerophosphoethanolamine concentrations were significantly higher (P < 0.05).
  
  
  CONCLUSIONS
  We report human in vivo hepatic T1s for phosphatidylcholine, NAD+, and UDPG for the first time at 7T. Our protocol allows high signal-to-noise, repeatable measurement of metabolite concentrations in human liver. The splitting of PDE into its constituent peaks at 7T may allow more insight into changes in metabolism. Magn Reson Med 78:2095-2105, 2017. © 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
authors.affiliation: Oxford Centre for Clinical Magnetic Resonance Research (OCMR), University of Oxford, Level 0, John Radcliffe Hospital, Oxford, United Kingdom.
authors.forename: Lucian A B
authors.initials: LAB
authors.lastname: Purvis
authors.affiliation: Oxford Centre for Clinical Magnetic Resonance Research (OCMR), University of Oxford, Level 0, John Radcliffe Hospital, Oxford, United Kingdom.
authors.forename: William T
authors.initials: WT
authors.lastname: Clarke
authors.affiliation: Oxford Centre for Clinical Magnetic Resonance Research (OCMR), University of Oxford, Level 0, John Radcliffe Hospital, Oxford, United Kingdom.|Department of Imaging Methods, Institute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia.
authors.forename: Ladislav
authors.initials: L
authors.lastname: Valkovič
authors.affiliation: Oxford Centre for Clinical Magnetic Resonance Research (OCMR), University of Oxford, Level 0, John Radcliffe Hospital, Oxford, United Kingdom.
authors.forename: Christina
authors.initials: C
authors.lastname: Levick
authors.affiliation: Oxford Centre for Clinical Magnetic Resonance Research (OCMR), University of Oxford, Level 0, John Radcliffe Hospital, Oxford, United Kingdom.|Translational Gastroenterology Unit, University of Oxford, United Kingdom.
authors.forename: Michael
authors.initials: M
authors.lastname: Pavlides
authors.affiliation: Translational Gastroenterology Unit, University of Oxford, United Kingdom.
authors.forename: Eleanor
authors.initials: E
authors.lastname: Barnes
authors.affiliation: Translational Gastroenterology Unit, University of Oxford, United Kingdom.
authors.forename: Jeremy F
authors.initials: JF
authors.lastname: Cobbold
authors.affiliation: Oxford Centre for Clinical Magnetic Resonance Research (OCMR), University of Oxford, Level 0, John Radcliffe Hospital, Oxford, United Kingdom.
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Robson
authors.affiliation: Oxford Centre for Clinical Magnetic Resonance Research (OCMR), University of Oxford, Level 0, John Radcliffe Hospital, Oxford, United Kingdom.
authors.forename: Christopher T
authors.initials: CT
authors.lastname: Rodgers
mesh_terms: D000328:Adult; D004952:Esters / Q000737:chemistry; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008099:Liver / Q000000981:diagnostic imaging*; D008103:Liver Cirrhosis / Q000000981:diagnostic imaging; D008107:Liver Diseases / Q000000981:diagnostic imaging*; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D010713:Phosphatidylcholines / Q000737:chemistry; D010758:Phosphorus / Q000737:chemistry*; D011786:Quality Control; D015203:Reproducibility of Results; D014532:Uridine Diphosphate Glucose / Q000737:chemistry; D055815:Young Adult
chemical_list: D004952:Esters; D010713:Phosphatidylcholines; D010758:Phosphorus; D014532:Uridine Diphosphate Glucose
keywords: 31P; 7 Tesla; cirrhosis; human; in vivo; liver; magnetic resonance spectroscopy; phosphorus