Tunable Ultrahigh Dielectric Constant (tuHDC) Ceramic Technique to Largely Improve RF Coil Efficiency and MR Imaging Performance.

This work introduces an innovative magnetic resonance (MR) imaging technology to incorporate radiofrequency (RF) coil(s) with permittivity-tunable ultrahigh dielectric constant (tuHDC) ceramics by controlling the ceramic temperature to optimize and significantly improve RF coil transmission and reception efficiencies, MR imaging sensitivity and signal-to-noise ratio (SNR). The tuHDC ceramics made of composite barium strontium titanate (BST) compounds (Ba0.6Sr0.4TiO3) have low dielectric loss and very high permittivity tunability from 2,000 to 15000 by varying the ceramic temperature between 0 degrees C to 40 degrees C to achieve an optimal permittivity for MR imaging application. We demonstrated for the first time the proof of concept using the BST-based tuHDC-RF-coil technology for improving MR spectroscopic imaging performance of 17O nuclide at 10.5 Tesla (T) at a low ceramic temperature and 23Na nuclide at 7T at room temperature. We discovered a large and spatially independent noise reduction under an optimal ceramic temperature, which synergistically resulted in an unprecedented SNR improvement. Large improvements were also demonstrated for 1H MRI on a 1.5T clinical scanner using the same ceramics. The tuHDC-RF-coil technology is highly robust, flexible and cost-effective; it presents a technical breakthrough to significantly improve imaging sensitivity and resolution for broad MR imaging applications; and is critical to advance biomedical and neuroscience research, and improve diagnostic imaging.