Stepped Impedance Resonators for High-Field Magnetic Resonance Imaging

Author

Akgun, Can E. ; DelaBarre, Lance ; Hyoungsuk Yoo ; Sung-Min Sohn ; Snyder, Carl J. ; Adriany, Gregor ; Ugurbil, K. ; Gopinath, Anand ; Vaughan, John Thomas

Author_Institution

Center for Magn. Resonance Res., Univ. of Minnesota, Minneapolis, MN, USA

Volume

61

Issue

2

fYear

2014

fDate

Feb. 2014

Firstpage

327

Lastpage

333

Abstract

Multi-element volume radio-frequency (RF) coils are an integral aspect of the growing field of high-field magnetic resonance imaging. In these systems, a popular volume coil of choice has become the transverse electromagnetic (TEM) transceiver coil consisting of microstrip resonators. In this paper, to further advance this design approach, a new microstrip resonator strategy in which the transmission line is segmented into alternating impedance sections, referred to as stepped impedance resonators (SIRs), is investigated. Single-element simulation results in free space and in a phantom at 7 T (298 MHz) demonstrate the rationale and feasibility of the SIR design strategy. Simulation and image results at 7 T in a phantom and human head illustrate the improvements in a transmit magnetic field, as well as RF efficiency (transmit magnetic field versus specific absorption rate) when two different SIR designs are incorporated in 8-element volume coil configurations and compared to a volume coil consisting of microstrip elements.

Keywords

biomedical MRI; coils; high-frequency transmission lines; medical image processing; microstrip resonators; phantoms; SIR design strategy; alternating impedance sections; free space; frequency 298 MHz; high-field magnetic resonance imaging; human head; magnetic flux density 7 T; microstrip resonator strategy; multielement volume radiofrequency coils; phantom; single-element simulation; specific absorption rate; stepped impedance resonators; transmission line; transverse electromagnetic transceiver coil; Coils; Impedance; Magnetic heads; Microstrip resonators; Phantoms; Radio frequency; Magnetic resonance imaging (MRI); microstrip; radio-frequency (RF) coils; stepped impedance resonator (SIR); transverse electromagnetic (TEM);

fLanguage

English

Journal_Title

Biomedical Engineering, IEEE Transactions on

Publisher

ieee

ISSN

0018-9294

Type

jour

DOI

10.1109/TBME.2013.2250973

Filename

6477090