title: Localized semi-LASER dynamic (31)P magnetic resonance spectroscopy of the soleus during and following exercise at 7 T.
abstract: OBJECTIVE
  This study demonstrates the applicability of semi-LASER localized dynamic (31)P MRS to deeper lying areas of the exercising human soleus muscle (SOL). The effect of accurate localization and high temporal resolution on data specificity is investigated.
  
  
  METHODS
  To achieve high signal-to-noise ratio (SNR) at a temporal resolution of 6 s, a custom-built human calf coil array was used at 7T. The kinetics of phosphocreatine (PCr) and intracellular pH were quantified separately in SOL and gastrocnemius medialis (GM) muscle of nine volunteers, during rest, plantar flexion exercise, and recovery.
  
  
  RESULTS
  The average SNR of PCr at rest was [Formula: see text] in SOL ([Formula: see text] in GM). End exercise PCr depletion in SOL ([Formula: see text] %) was far lower than in GM ([Formula: see text] %). The pH in SOL increased rapidly and, in contrast to GM, remained elevated until the end of exercise.
  
  
  CONCLUSIONS
  (31)P MRS in single-shots every 6 s localized in the deeper-lying SOL enabled quantification of PCr recovery times at low depletions and of fast pH changes, like the initial rise. Both high temporal resolution and accurate spatial localization improve specificity of Pi and, thus, pH quantification by avoiding multiple, and potentially indistinguishable sources for changing the Pi peak shape.
authors.affiliation: Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Austria.|MR Centre of Excellence, Medical University of 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, Austria.|MR Centre of Excellence, Medical University of Vienna, Austria.
authors.forename: Martin
authors.initials: M
authors.lastname: Meyerspeer
authors.affiliation: Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Austria.|MR Centre of Excellence, Medical University of 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, Austria.|MR Centre of Excellence, Medical University of Vienna, Austria.
authors.forename: Sigrun
authors.initials: S
authors.lastname: Goluch
authors.affiliation: Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Austria.|MR Centre of Excellence, Medical University of Vienna, Austria.
authors.forename: Kiril
authors.initials: K
authors.lastname: Schewzow
authors.affiliation: Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Austria.|MR Centre of Excellence, Medical University of Vienna, Austria.
authors.forename: Elmar
authors.initials: E
authors.lastname: Laistler
authors.affiliation: Department of Pharmaceutical Chemistry, Semmelweis University, Budapest, Hungary.|Research Group of Drugs of Abuse and Doping Agents, Hungarian Academy of Sciences, Budapest, Hungary.
authors.forename: Arash
authors.initials: A
authors.lastname: Mirzahosseini
authors.affiliation: Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Austria.|MR Centre of Excellence, Medical University of Vienna, Austria.|Graz University of Technology, Institute of Medical Engineering, Austria.
authors.forename: Fabian
authors.initials: F
authors.lastname: Niess
authors.affiliation: Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Austria.
authors.forename: Ewald
authors.initials: E
authors.lastname: Unger
authors.affiliation: Department of Clinical Pharmacology, Medical University of Vienna, Austria.
authors.forename: Michael
authors.initials: M
authors.lastname: Wolzt
authors.affiliation: Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Austria.|MR Centre of Excellence, Medical University of Vienna, Austria.
authors.forename: Ewald
authors.initials: E
authors.lastname: Moser
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D007834:Lasers; D009682:Magnetic Resonance Spectroscopy / Q000295:instrumentation*; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology*; D010725:Phosphocreatine / Q000378:metabolism*; D010759:Phosphorus Isotopes / Q000493:pharmacokinetics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult
chemical_list: D010759:Phosphorus Isotopes; D010725:Phosphocreatine
keywords: In vivo NMR spectroscopy; Phosphocreatine; Physical exertion; Skeletal muscle; Soleus muscle