Title :
Ultrahigh-field MRI whole-slice and localized RF field excitations using the same RF transmit array
Author :
Ibrahim, Tamer S.
Author_Institution :
Sch. of Electr. & Comput. Eng., Pittsburgh Univ., PA
Abstract :
In this paper, a multiport driving mechanism is numerically implemented at ultra high-field (UHF) magnetic resonance imaging (MRI) to provide 1) homogenous whole-slice (axial, sagittal, or coronal) and 2) highly localized radio frequency (RF) field excitation within the same slices, all with the same RF transmit array (here chosen to be a standard transverse electromagnetic (TEM) resonator/coil). The method is numerically tested using a full-wave model of a TEM coil loaded with a high-resolution/18-tissue/anatomically detailed human head mesh. The proposed approach is solely based on electromagnetic and phased array antenna theories. The results demonstrate that both homogenous whole-slice as well as localized RF excitation can be achieved within any slice of the head at 7 T (298 MHz for proton imaging)
Keywords :
antenna phased arrays; biomedical MRI; coils; mesh generation; resonators; 298 MHz; 7 T; coil; electromagnetic theory; high-resolution anatomically detailed human head mesh; localized RF field excitations; magnetic resonance imaging; multiport driving mechanism; phased array antenna theory; same RF transmit array; transverse electromagnetic resonator; ultrahigh-field MRI whole-slice radio frequency field excitation; Antenna arrays; Coils; Electromagnetic fields; Humans; Magnetic heads; Magnetic resonance imaging; Microwave antenna arrays; Phased arrays; Radio frequency; Testing; Finite-difference time-domain (FDTD); RF field homogeneity; RF field localization; modeling; optimization; radio frequency (RF) coils; ultrahigh-field (UHF) magnetic resonance imaging (MRI);
Journal_Title :
Medical Imaging, IEEE Transactions on
DOI :
10.1109/TMI.2006.880666