Surface coil based on a dielectric resonator tuned to the higher-order modes

Abstract

Magnetic resonance (MR) images spatial resolution, which is a key factor in early diagnosis of many diseases, is fundamentally limited by the signal-to-noise ratio, which in turn depends upon the efficiency of the receive radiofrequency coils design. Many various multi-channel coils were designed to improve the quality of MR images. Another way to enhance the quality of magnetic resonance imaging (MRI) is the implementation of resonators based on novel materials, such as high-permittivity dielectrics. Here, we investigate the potential for the sensitivity enhancement with higher-order modes of dielectric resonators. We numerically show that because of the unique near field spatial distribution of a dielectric resonator third-order mode, the receive performance can be substantially improved in comparison with a conventional metallic loop coil of the same dimensions. Moreover, we study the performance of the dielectric resonator in comparison with a metallic loop coil, which size was optimized to match the sensitivity of the resonator at a particular distance. We demonstrate a 9-fold larger planar field-of-view with the dielectric resonator than with the loop coil. Our work provides the design guidelines for the improvement of near-field MRI sensitivity with the dielectric resonators.