RF multi-channel head coil design with improved B 1 + Fields uniformity for high field MRI systems

Sung Min Sohn, Lance Delabarre, John Thomas Vaughan, Anand Gopinath

Research output: Chapter in Book/Report/Conference proceedingConference contribution

8 Scopus citations

Abstract

In ultra high field MRI systems (7 tesla and higher), the wavelength inside the body is short and smaller than the human anatomy at the Larmor frequency. At these shorter wavelengths, interference effects appear; the uniformity of the RF excitation B 1 + field over the whole subject becomes inhomogeneous. The RF B 1 + field generated by the RF coil is a maximum in the center along the length of the coil microstrip element and falls off towards both ends of the coil element and it leads to anomalous contrast in the MR images. In this study, double trapezoid-like shape along the length of the microstrip resonator is proposed to obtain gradual impedance variation and flatten transmission near-field profile along the length of the coil. The conventional and proposed 8 channel head coils were investigated with a phantom in a 7 tesla MRI scanner. The results show very flat field distribution with about 35% increased local transmission magnetic field strengths at the end sides as well as about 13% improvement at the center and the Q (quality factor) ratio between unloaded and loaded is also increased about 45% (from L.46 to 2.13) compared to the conventional structure.

Original languageEnglish (US)
Title of host publicationIMS 2012 - 2012 IEEE MTT-S International Microwave Symposium
DOIs
StatePublished - Oct 3 2012
Externally publishedYes
Event2012 IEEE MTT-S International Microwave Symposium, IMS 2012 - Montreal, QC, Canada
Duration: Jun 17 2012Jun 22 2012

Publication series

NameIEEE MTT-S International Microwave Symposium Digest
ISSN (Print)0149-645X

Other

Other2012 IEEE MTT-S International Microwave Symposium, IMS 2012
CountryCanada
CityMontreal, QC
Period6/17/126/22/12

Keywords

  • Magnetic resonance imaging (MRI)
  • Microstrip antennas
  • RF coils
  • RF shimming

ASJC Scopus subject areas

  • Radiation
  • Condensed Matter Physics
  • Electrical and Electronic Engineering

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    Sohn, S. M., Delabarre, L., Vaughan, J. T., & Gopinath, A. (2012). RF multi-channel head coil design with improved B 1 + Fields uniformity for high field MRI systems. In IMS 2012 - 2012 IEEE MTT-S International Microwave Symposium [6259669] (IEEE MTT-S International Microwave Symposium Digest). https://doi.org/10.1109/MWSYM.2012.6259669