title: The Travelling-Wave Primate System: A New Solution for Magnetic Resonance Imaging of Macaque Monkeys at 7 Tesla Ultra-High Field.
abstract: BACKGROUND
  Neuroimaging of macaques at ultra-high field (UHF) is usually conducted by combining a volume coil for transmit (Tx) and a phased array coil for receive (Rx) tightly enclosing the monkey's head. Good results have been achieved using vertical or horizontal magnets with implanted or near-surface coils. An alternative and less costly approach, the travelling-wave (TW) excitation concept, may offer more flexible experimental setups on human whole-body UHF magnetic resonance imaging (MRI) systems, which are now more widely available. Goal of the study was developing and validating the TW concept for in vivo primate MRI.
  
  
  METHODS
  The TW Primate System (TWPS) uses the radio frequency shield of the gradient system of a human whole-body 7 T MRI system as a waveguide to propagate a circularly polarized B1 field represented by the TE11 mode. This mode is excited by a specifically designed 2-port patch antenna. For receive, a customized neuroimaging monkey head receive-only coil was designed. Field simulation was used for development and evaluation. Signal-to-noise ratio (SNR) was compared with data acquired with a conventional monkey volume head coil consisting of a homogeneous transmit coil and a 12-element receive coil.
  
  
  RESULTS
  The TWPS offered good image homogeneity in the volume-of-interest Turbo spin echo images exhibited a high contrast, allowing a clear depiction of the cerebral anatomy. As a prerequisite for functional MRI, whole brain ultrafast echo planar images were successfully acquired.
  
  
  CONCLUSIONS
  The TWPS presents a promising new approach to fMRI of macaques for research groups with access to a horizontal UHF MRI system.
authors.affiliation: Department of Biometrics and Medical Informatics, OvG University, Magdeburg, Germany.
authors.forename: Tim
authors.initials: T
authors.lastname: Herrmann
authors.affiliation: Department of Biometrics and Medical Informatics, OvG University, Magdeburg, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Mallow
authors.affiliation: Department of Biometrics and Medical Informatics, OvG University, Magdeburg, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Plaumann
authors.affiliation: Department of Biometrics and Medical Informatics, OvG University, Magdeburg, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Luchtmann
authors.affiliation: Leibniz Institute for Neurobiology (LIN), Magdeburg, Germany.
authors.forename: Jörg
authors.initials: J
authors.lastname: Stadler
authors.affiliation: Leibniz Institute for Neurobiology (LIN), Magdeburg, Germany.
authors.forename: Judith
authors.initials: J
authors.lastname: Mylius
authors.affiliation: Leibniz Institute for Neurobiology (LIN), Magdeburg, Germany; Center for Behavioral Brain Sciences, Magdeburg, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Brosch
authors.affiliation: Department of Biometrics and Medical Informatics, OvG University, Magdeburg, Germany; Center for Behavioral Brain Sciences, Magdeburg, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Bernarding
mesh_terms: D000818:Animals; D001921:Brain / Q000502:physiology; D004867:Equipment Design; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008251:Macaca; D008279:Magnetic Resonance Imaging / Q000295:instrumentation* / Q000379:methods*; D059906:Neuroimaging / Q000295:instrumentation / Q000379:methods*; D011846:Radio Waves