title: Interleaved multivoxel31P MR spectroscopy.
abstract: Separate measurements are required when investigating multiple exercising muscles with singlevoxel-localized dynamic31P-MRS. With multivoxel spectroscopy,31P-MRS time-series spectra are acquired from multiple independent regions during one exercise-recovery experiment with the same time resolution as for singlevoxel measurements.
  
  
  
  Multiple independently selected volumes were localized using temporally interleaved semi-LASER excitations at 7T. Signal loss caused by mutual saturation from shared excitation or refocusing slices was quantified at partial and full overlap, and potential contamination was investigated in phantom measurements. During an exercise-recovery experiment both gastrocnemius medialis and soleus of two healthy volunteers were measured using multivoxel acquisitions with a total TRof 6 s, while avoiding overlap of excitation slices.
  
  
  
  Signal reduction by shared adiabatic refocusing slices selected 1 s after the preceding voxel was between 10% (full overlap) and 20% (half overlap), in a phantom measurement. In vivo data were acquired from both muscles within the same exercise experiment, with 13-18% signal reduction. Spectra show phosphocreatine, inorganic phosphate, adenosine-triposphate, phosphomonoesters, and phosphodiesters.
  
  
  
  Signal decrease was relatively low compared to the 2-fold increase in information. The approach could help to improve the understanding in metabolic research and is applicable to other organs and nuclei. Magn Reson Med 77:921-927, 2017. © 2016 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: Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.|MR Center of Excellence, Medical University of Vienna, Vienna, Austria.|Faculty of Physics, Technical University of Vienna, Vienna, Austria.
authors.forename: Fabian
authors.initials: F
authors.lastname: Niess
authors.affiliation: Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.|MR Center of Excellence, Medical University of Vienna, Vienna, Austria.
authors.forename: Georg B
authors.initials: GB
authors.lastname: Fiedler
authors.affiliation: Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.|MR Center of Excellence, Medical University of Vienna, Vienna, Austria.
authors.forename: Albrecht I
authors.initials: AI
authors.lastname: Schmid
authors.affiliation: Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.|MR Center of Excellence, Medical University of Vienna, Vienna, Austria.|Division of Endocrinology and Metabolism, Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria.
authors.forename: Sigrun
authors.initials: S
authors.lastname: Goluch
authors.affiliation: Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.|MR Center of Excellence, Medical University of Vienna, Vienna, Austria.
authors.forename: Roberta
authors.initials: R
authors.lastname: Kriegl
authors.affiliation: Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria.
authors.forename: Michael
authors.initials: M
authors.lastname: Wolzt
authors.affiliation: Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.|MR Center of Excellence, Medical University of Vienna, Vienna, Austria.
authors.forename: Ewald
authors.initials: E
authors.lastname: Moser
authors.affiliation: Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.|MR Center of Excellence, Medical University of Vienna, Vienna, Austria.
authors.forename: Martin
authors.initials: M
authors.lastname: Meyerspeer
mesh_terms: D000465:Algorithms; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D057054:Molecular Imaging / Q000379:methods; D018482:Muscle, Skeletal / Q000502:physiology*; D017553:Phosphorus Compounds / Q000378:metabolism*; D010759:Phosphorus Isotopes / Q000493:pharmacokinetics*; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D017553:Phosphorus Compounds; D010759:Phosphorus Isotopes; D019275:Radiopharmaceuticals
keywords: dynamic 31P MRS; exercising muscle; multivoxel; spectroscopic localization