title: An inverse methodology for high frequency RF head coil design with preemphasized B/sub 1/ field in MRI.
abstract: An inverse methodology to assist in the design of radio-frequency (RF) head coils for high field MRI application is described in this work. Free space time-harmonic electromagnetic Green's functions and preemphasized B/sub 1/ field are used to calculate the current density on the coil cylinder. With B/sub 1/ field preemphasized and lowered in the middle of the RF transverse plane, the calculated current distribution can generate an internal magnetic field that can reduce the EM field/tissue interactions at high frequencies. The current distribution of a head coil operating at 4 T is calculated using inverse methodology with preemphasized B/sub 1/ fields. FDTD is employed to calculate B/sub 1/ field and signal intensity inside a homogenous cylindrical phantom and human head. A comparison with conventional RF birdcage coil is reported here and demonstrated that inverse-method designed coil with preemphasized B/sub 1/ field can help in decreasing the notorious bright region caused by EM field/tissue interactions in the human head images at 4 T.
authors.affiliation: Sch. of Inf. Technol. & Electr. Eng., Queensland Univ., Brisbane, Qld., Australia.
authors.forename: B
authors.initials: B
authors.lastname: Xu
authors.forename: S
authors.initials: S
authors.lastname: Crozier
authors.forename: B K
authors.initials: BK
authors.lastname: Li
authors.forename: Q
authors.initials: Q
authors.lastname: Wei
authors.forename: F
authors.initials: F
authors.lastname: Liu