Multilayered RF Coil System for Improving Transmit B1 Field Homogeneity in High-Field MRI

Description:

Available for licensing and commercial development is a multilayered radio-frequency (RF) coil system for improving the transmit B1 field homogeneity for magnetic resonance imaging (MRI) at high field strengths. The current invention aims at manipulating the inhomogeneous profile of the transmit B1 field, which causes MR images to become less uniform as the magnetic field strength is increased, by utilizing an inner array of RF elements (e.g. surface coils) within and coupled to an outer transmit unit (e.g. a birdcage coil or other volume coil). Improvement in B1 field homogeneity is achieved by tuning the surface coils of the inner layer to an appropriate resonant frequency and then passively coupling them to the outer-layer volume coil. Furthermore, the amount of coupling is determined by the intrinsic properties of the transmit unit and can be adjusted accordingly. The current design provides an effective approach for reducing B1 field homogeneity at high fields and can be implemented without the need for independent RF channels, thereby reducing MRI system complexity. Furthermore it can be readily implemented on existing MRI coil systems by detuning surface coils rather than decoupling them during the transmit phase.