Using a whole-body 31P birdcage transmit coil and 16-element receive array for human cardiac metabolic imaging at 7T.

Autor: Valkovič L; Oxford Centre for Clinical Magnetic Resonance Research (OCMR), BHF Centre of Research Excellence, University of Oxford, Oxford, United Kingdom.; Department of Imaging Methods, Institute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia., Dragonu I; Siemens Healthcare Limited, Frimley, United Kingdom., Almujayyaz S; MR Coils BV, Zaltbommel, Netherlands., Batzakis A; MR Coils BV, Zaltbommel, Netherlands., Young LAJ; Oxford Centre for Clinical Magnetic Resonance Research (OCMR), BHF Centre of Research Excellence, University of Oxford, Oxford, United Kingdom., Purvis LAB; Oxford Centre for Clinical Magnetic Resonance Research (OCMR), BHF Centre of Research Excellence, University of Oxford, Oxford, United Kingdom., Clarke WT; Oxford Centre for Clinical Magnetic Resonance Research (OCMR), BHF Centre of Research Excellence, University of Oxford, Oxford, United Kingdom., Wichmann T; Rapid Biomedical GmbH, Rimpar, Germany., Lanz T; Rapid Biomedical GmbH, Rimpar, Germany., Neubauer S; Oxford Centre for Clinical Magnetic Resonance Research (OCMR), BHF Centre of Research Excellence, University of Oxford, Oxford, United Kingdom., Robson MD; Oxford Centre for Clinical Magnetic Resonance Research (OCMR), BHF Centre of Research Excellence, University of Oxford, Oxford, United Kingdom., Klomp DWJ; MR Coils BV, Zaltbommel, Netherlands.; Department of Radiology, University Medical Center Utrecht, Utrecht, Netherlands., Rodgers CT; Oxford Centre for Clinical Magnetic Resonance Research (OCMR), BHF Centre of Research Excellence, University of Oxford, Oxford, United Kingdom.
Jazyk: angličtina
Zdroj: PloS one [PLoS One] 2017 Oct 26; Vol. 12 (10), pp. e0187153. Date of Electronic Publication: 2017 Oct 26 (Print Publication: 2017).
DOI: 10.1371/journal.pone.0187153
Abstrakt: Purpose: Cardiac phosphorus magnetic resonance spectroscopy (31P-MRS) provides unique insight into the mechanisms of heart failure. Yet, clinical applications have been hindered by the restricted sensitivity of the surface radiofrequency-coils normally used. These permit the analysis of spectra only from the interventricular septum, or large volumes of myocardium, which may not be meaningful in focal disease. Löring et al. recently presented a prototype whole-body (52 cm diameter) transmit/receive birdcage coil for 31P at 7T. We now present a new, easily-removable, whole-body 31P transmit radiofrequency-coil built into a patient-bed extension combined with a 16-element receive array for cardiac 31P-MRS.
Materials and Methods: A fully-removable (55 cm diameter) birdcage transmit coil was combined with a 16-element receive array on a Magnetom 7T scanner (Siemens, Germany). Electro-magnetic field simulations and phantom tests of the setup were performed. In vivo maps of B1+, metabolite signals, and saturation-band efficiency were acquired across the torsos of eight volunteers.
Results: The combined (volume-transmit, local receive array) setup increased signal-to-noise ratio 2.6-fold 10 cm below the array (depth of the interventricular septum) compared to using the birdcage coil in transceiver mode. The simulated coefficient of variation for B1+ of the whole-body coil across the heart was 46.7% (surface coil 129.0%); and the in vivo measured value was 38.4%. Metabolite images of 2,3-diphosphoglycerate clearly resolved the ventricular blood pools, and muscle tissue was visible in phosphocreatine (PCr) maps. Amplitude-modulated saturation bands achieved 71±4% suppression of phosphocreatine PCr in chest-wall muscles. Subjects reported they were comfortable.
Conclusion: This easy-to-assemble, volume-transmit, local receive array coil combination significantly improves the homogeneity and field-of-view for metabolic imaging of the human heart at 7T.
Databáze: MEDLINE
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