Coupled ceramic resonators for clinical MRI applications

Dielectric resonators based on high permittivity materials with low losses have recommended themselves as good candidates for improving magnetic resonance imaging (MRI) characteristics. Mainly due to the ability to focus and enhance the radiofrequency (RF) magnetic field, they are promising alternatives to dedicated cable-connected RF coils. In this work, we investigate a system of coupled, very-high permittivity dielectric resonators for bilateral breast MRI at 3T. The resonators are implemented as a pair of coaxial hollow cylinders consisting of ceramic rings, which are inductively coupled with a birdcage coil of the MRI machine. We investigated the behavior of antisymmetric and symmetric TE-modes of two coupled resonators. Via electromagnetic simulations, we verified that the symmetric mode of coupled dielectric resonators could be effectively excited with birdcage coil, focusing RF magnetic field in the region of interest, thereby realizing targeted MRI concept.