High-Permittivity Dielectric Probes for Ultra-High Field MR Microscopy at 17.2 T
Résumé
We propose a theoretical model predicting the Signal-to-Noise Ratio (SNR) of dielectric antennas for Magnetic Resonance Imaging. The SNR is estimated with a semi-analytical approach describing the first transverse electric mode of a high-permittivity ring resonator. When the ring is properly excited with a feeding loop, it induces a strong magnetic field in the sample while dielectric losses are limited due to low electric field intensity in this region. The proposed model is validated with numerical simulations regarding microscopy applications and its prediction confirmed experimentally at 17.2 T. Summary of main findings An alternative design of MR microscopy probes, based on dielectric ring resonators, is studied. A theoretical model for the achievable SNR is proposed and a prototype is built. It enables, at 17.2 T, a twofold SNR enhancement compared to the conventional solenoid, as predicted by the model.
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