title: A form-fitted three channel (31) P, two channel (1) H transceiver coil array for calf muscle studies at 7 T.
abstract: OBJECTIVE
  To enhance sensitivity and coverage for calf muscle studies, a novel, form-fitted, three-channel phosphorus-31 ((31) P), two-channel proton ((1) H) transceiver coil array for 7 T MR imaging and spectroscopy is presented.
  
  
  METHODS
  Electromagnetic simulations employing individually generated voxel models were performed to design a coil array for studying nonpathological muscle metabolism. Static phase combinations of the coil elements' transmit fields were optimized based on homogeneity and efficiency for several voxel models. The best-performing design was built and tested both on phantoms and in vivo.
  
  
  RESULTS
  Simulations revealed that a shared conductor array for (31) P provides more robust interelement decoupling and better homogeneity than an overlap array in this configuration. A static B1 (+) shim setting that suited various calf anatomies was identified and implemented. Simulations showed that the (31) P array provides signal-to-noise ratio (SNR) benefits over a single loop and a birdcage coil of equal radius by factors of 3.2 and 2.6 in the gastrocnemius and by 2.5 and 2.0 in the soleus muscle.
  
  
  CONCLUSIONS
  The performance of the coil in terms of B1 (+) and achievable SNR allows for spatially localized dynamic (31) P spectroscopy studies in the human calf. The associated higher specificity with respect to nonlocalized measurements permits distinguishing the functional responses of different muscles.
authors.affiliation: Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.|MR Centre of Excellence, 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 Centre of Excellence, Medical University of Vienna, Vienna, Austria.
authors.forename: Andre
authors.initials: A
authors.lastname: Kuehne
authors.affiliation: Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.|MR Centre of Excellence, Medical University of Vienna, Vienna, Austria.
authors.forename: Martin
authors.initials: M
authors.lastname: Meyerspeer
authors.affiliation: Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.|MR Centre of Excellence, Medical University of Vienna, Vienna, Austria.|IR4M (Imagerie par Résonance Magnétique Médicale et Multi-Modalités), UMR808, Université Paris Sud-CNRS, Orsay, France.
authors.forename: Roberta
authors.initials: R
authors.lastname: Kriegl
authors.affiliation: Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.|MR Centre 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 Centre of Excellence, Medical University of Vienna, Vienna, Austria.
authors.forename: Georg B
authors.initials: GB
authors.lastname: Fiedler
authors.affiliation: Department of Biometrics and Medicine Informatics, Otto von Guericke University Magdeburg, Magdeburg, Germany.
authors.forename: Tim
authors.initials: T
authors.lastname: Herrmann
authors.affiliation: Department of Biometrics and Medicine Informatics, Otto von Guericke University Magdeburg, Magdeburg, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Mallow
authors.affiliation: Neuroscience Research Institute, Gachon University, Incheon, Korea.
authors.forename: Suk-Min
authors.initials: SM
authors.lastname: Hong
authors.affiliation: Neuroscience Research Institute, Gachon University, Incheon, Korea.
authors.forename: Zang-Hee
authors.initials: ZH
authors.lastname: Cho
authors.affiliation: Department of Biometrics and Medicine Informatics, Otto von Guericke University Magdeburg, Magdeburg, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Bernarding
authors.affiliation: Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.|MR Centre 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 Centre of Excellence, Medical University of Vienna, Vienna, Austria.
authors.forename: Elmar
authors.initials: E
authors.lastname: Laistler
mesh_terms: D000328:Adult; D003198:Computer Simulation; D004867:Equipment Design; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D007089:Image Enhancement / Q000295:instrumentation*; D007866:Leg; D008279:Magnetic Resonance Imaging / Q000295:instrumentation*; D008297:Male; D018482:Muscle, Skeletal / Q000033:anatomy & histology*; D019047:Phantoms, Imaging; D010759:Phosphorus Isotopes
chemical_list: D010759:Phosphorus Isotopes
keywords: 31P spectroscopy, EM simulation, coil array, ultra-high field, X-nuclei sensitivity, RF coil design