Development and Experimental Testing of Microstrip Patch Antenna-Inspired RF Probes for 14 T MRI Scanners

Navid P. Gandji, Gangchea Lee, George Semouchkin, Elena Semouchkina, Thomas Neuberger, Michael T. Lanagan

Research output: Contribution to journalArticle

Abstract

Radio frequency (RF) probes for ultrahigh-field magnetic resonance imaging (MRI) systems were developed from structures inspired by microstrip patch antennas. The patch structures provide an alternative to conventional surface coils. We show that these structures, operating as resonators, can produce strong magnetic fields, which act as B1 fields in MRI studies. The addition of high permittivity inserts to the patch substrate was beneficial for increasing B1 field uniformity. It was also shown by simulations that two vis-à-vis placed identical patches fed with 180° phase difference could produce uniform B1 field in the space between patches and could be used as volume RF probes. This possibility was confirmed by experiments with fabricated prototypes in the VARIAN 14.1 T MRI scanner. We further show that the B1 uniformity is enhanced over larger volume with properly profiled substrates of higher permittivity, along with smaller radiation losses. These probes were found competitive and even advantageous in comparison with birdcage coils because of better stability of their Q-factors at loading by lossy phantoms. Thus, patch-based probes offer a viable alternative to RF probes for ultrahigh field MRI.

Original languageEnglish (US)
Article number8510824
Pages (from-to)443-453
Number of pages11
JournalIEEE Transactions on Microwave Theory and Techniques
Volume67
Issue number1
DOIs
StatePublished - Jan 1 2019

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patch antennas
microstrip antennas
Magnetic resonance
Microstrip antennas
scanners
magnetic resonance
radio frequencies
Imaging techniques
probes
Testing
Permittivity
coils
permittivity
Substrates
inserts
Imaging systems
Q factors
Resonators
resonators
prototypes

All Science Journal Classification (ASJC) codes

  • Radiation
  • Condensed Matter Physics
  • Electrical and Electronic Engineering

Cite this

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abstract = "Radio frequency (RF) probes for ultrahigh-field magnetic resonance imaging (MRI) systems were developed from structures inspired by microstrip patch antennas. The patch structures provide an alternative to conventional surface coils. We show that these structures, operating as resonators, can produce strong magnetic fields, which act as B1 fields in MRI studies. The addition of high permittivity inserts to the patch substrate was beneficial for increasing B1 field uniformity. It was also shown by simulations that two vis-{\`a}-vis placed identical patches fed with 180° phase difference could produce uniform B1 field in the space between patches and could be used as volume RF probes. This possibility was confirmed by experiments with fabricated prototypes in the VARIAN 14.1 T MRI scanner. We further show that the B1 uniformity is enhanced over larger volume with properly profiled substrates of higher permittivity, along with smaller radiation losses. These probes were found competitive and even advantageous in comparison with birdcage coils because of better stability of their Q-factors at loading by lossy phantoms. Thus, patch-based probes offer a viable alternative to RF probes for ultrahigh field MRI.",
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Development and Experimental Testing of Microstrip Patch Antenna-Inspired RF Probes for 14 T MRI Scanners. / Gandji, Navid P.; Lee, Gangchea; Semouchkin, George; Semouchkina, Elena; Neuberger, Thomas; Lanagan, Michael T.

In: IEEE Transactions on Microwave Theory and Techniques, Vol. 67, No. 1, 8510824, 01.01.2019, p. 443-453.

Research output: Contribution to journalArticle

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