title: Optimized radiofrequency coil setup for MR examination of living isolated rat hearts in a horizontal 9.4T magnet.
abstract: OBJECTIVE
  (i) To optimize an MR-compatible organ perfusion setup for the nondestructive investigation of isolated rat hearts by placing the radiofrequency (RF) coil inside the perfusion chamber; (ii) to characterize the benefit of this system for diffusion tensor imaging and proton ((1) H-) MR spectroscopy.
  
  
  METHODS
  Coil quality assessment was conducted both on the bench, and in the magnet. The benefit of the new RF-coil was quantified by measuring signal-to-noise ratio (SNR), accuracy, and precision of diffusion tensor imaging/error in metabolite amplitude estimation, and compared to an RF-coil placed externally to the perfusion chamber.
  
  
  RESULTS
  The new design provided a 59% gain in signal-to-noise ratio on a fixed rat heart compared to using an external resonator, which found reflection in an improvement of living heart data quality, compared to previous external resonator studies. This resulted in 14-29% improvement in accuracy and precision of diffusion tensor imaging. The Cramer-Rao lower bounds for metabolite amplitude estimations were up to 5-fold smaller.
  
  
  CONCLUSIONS
  Optimization of MR-compatible perfusion equipment advances the study of rat hearts with improved signal-to-noise ratio performance, and thus improved accuracy/precision.
authors.affiliation: Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK.
authors.forename: Maelene
authors.initials: M
authors.lastname: Lohezic
authors.affiliation: National Heart and Lung Institute, Imperial College London, London, UK.|Qatar Cardiovascular Research Center, Qatar Foundation, Doha, Qatar.
authors.forename: Christian
authors.initials: C
authors.lastname: Bollensdorff
authors.affiliation: Rapid Biomedical GmbH, Rimpar, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Korn
authors.affiliation: Rapid Biomedical GmbH, Rimpar, Germany.
authors.forename: Titus
authors.initials: T
authors.lastname: Lanz
authors.affiliation: Department of Engineering Science, University of Oxford, Oxford, UK.
authors.forename: Vicente
authors.initials: V
authors.lastname: Grau
authors.affiliation: National Heart and Lung Institute, Imperial College London, London, UK.|Department of Computer Science, University of Oxford, Oxford, UK.
authors.forename: Peter
authors.initials: P
authors.lastname: Kohl
authors.affiliation: Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK.
authors.forename: Jürgen E
authors.initials: JE
authors.lastname: Schneider
mesh_terms: D000818:Animals; D004867:Equipment Design; D006321:Heart / Q000033:anatomy & histology*; D007089:Image Enhancement / Q000295:instrumentation*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation*; D051381:Rats; D017207:Rats, Sprague-Dawley; D059629:Signal-To-Noise Ratio
keywords: Langendorff perfusion; cardiac magnetic resonance imaging; diffusion tensor imaging; proton spectroscopy; radiofrequency coil