Abstract
The uniform flip angle throughout the imaging region is the requirement to the RF transmit subsystem. It started as solenoid and saddle coils, followed by the slotted tube resonator. And the birdcage coil, which produces very uniform RF field with the quadrature excitation, was commonly accepted as the solution. However, the wavelength effect and high SAR due to the increased strength of the static magnetic field are requiring further evolution of the RF transmit system now. This paper reviews the basic technique of MRI transmission and solution in high field MRI.
