A Coaxial RF Applicator for Ultra-High Field Human MRI

Georgiy Solomakha, Anna Andreychenko, Pierre-Francois van de Moortele, H. Kroeze, Alexander J. Raaijmakers, F. E. Euwe, J. J. W. Lagendijk, P. R. Luijten, C. A. T. van den Berg

Research output: Contribution to journalArticleAcademicpeer-review


To develop a novel radio-frequency (RF) concept for ultra-high field (UHF) human magnetic resonance imaging (MRI) based on a coaxial resonant cavity. Methods: A two-channel slotted coaxial cavity RF applicator was designed for human head MRI at 9.4T. Physical dimensions made the proposed conducting structure resonant at the required frequency without tuning lumped elements. Numerical electromagnetic modeling was used to optimize the design. RF safety was assessed with two representative human body models. MR experiments on a 9.4T scanner included gradient echo images and mapping of a circularly polarized RF magnetic field in the human head phantom. Results: The simulations and the phantom MR experiments agreed both qualitatively and quantitatively. The design was relatively simple, robust and required only a few additional reactive elements for the applicator's input impedance matching. The transmit efficiency and homogeneity of the excitation field were only 20% and 4% lower compared to a conventional 8-channel head array. Conclusion: The coaxial RF applicator was feasible for human MRI at UHF and required no lumped elements for its tuning. Imaging performance of the RF applicator was only moderately lower compared to the conventional transmit array, but would be sufficient to provide an anatomical reference for the heteronuclei MRI. Significance: An alternative approach with the minimal involvement of lumped elements becomes feasible to design volume-type RF coils for UHF human MRI.

Original languageEnglish
Article number8632760
Pages (from-to)2848-2854
Number of pages7
JournalIEEE Transactions on Biomedical Engineering
Issue number10
Publication statusPublished - Oct 2019


  • Coaxial radio-frequency applicator
  • resonant cavity
  • waveguide
  • ultra high field
  • 9.4T


Dive into the research topics of 'A Coaxial RF Applicator for Ultra-High Field Human MRI'. Together they form a unique fingerprint.

Cite this