Excitation and RF field control of a human-size 10.5-T MRI system

Patrick Bluem, Pierre-Francois Van de Moortele, Gregor Adriany, Zoya Popovic

Research output: Contribution to journalArticle

Abstract

This paper presents an investigation of methods for improving homogeneity inside various dielectric phantoms situated in a 10.5-T human-sized magnetic resonance imaging. The transmit B1 (B+ 1 ) field is excited with a quadrature-fed circular patch probe and a 12-element capacitively loaded microstrip array. Both simulations and measurements show improved homogeneity in a cylindrical water phantom, an inhomogeneous phantom (pineapple), and a NIST standard phantom. The simulations are performed using a full-wave finite-difference time-domain solver (Sim4Life) in order to find the B+ 1 field distribution and compared to the gradient-recalled echo image and efficiency result. For additional field uniformity, the wall electromagnetic boundary conditions are modified with a passive quadrifilar helix. Finally, these methods are applied in simulation to head imaging of an anatomically correct human body model (Duke, IT'IS Virtual Population) showing improved homogeneity and specific absorption rate for various excitations.

Original languageEnglish (US)
Article number8576556
Pages (from-to)1184-1196
Number of pages13
JournalIEEE Transactions on Microwave Theory and Techniques
Volume67
Issue number3
DOIs
StatePublished - Mar 1 2019

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Magnetic resonance imaging
homogeneity
Imaging techniques
Magnetic resonance
excitation
simulation
Boundary conditions
human body
quadratures
helices
magnetic resonance
echoes
boundary conditions
electromagnetism
Water
gradients
probes
water

Keywords

  • Finite-difference time domain (FDTD)
  • magnetic resonance imaging (MRI)
  • patch antenna
  • waveguide

Cite this

Excitation and RF field control of a human-size 10.5-T MRI system. / Bluem, Patrick; Van de Moortele, Pierre-Francois; Adriany, Gregor; Popovic, Zoya.

In: IEEE Transactions on Microwave Theory and Techniques, Vol. 67, No. 3, 8576556, 01.03.2019, p. 1184-1196.

Research output: Contribution to journalArticle

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