Efficient RF Shimming Strategies for Cardiac MRI at 5T

Motivation: Enhance RF shim efficiency, reduce power, and provide uniformity for ultra-high field cardiac imaging. Goal(s): To significantly enhance excitation efficiency, reduce excitation power, and mitigate the risk of SAR exceeding safe levels, while minimizing loss of uniformity. Approach: Optimizing excitation intensity and uniformity through joint loss function and validating the approach with simulation models and in vivo imaging. Results: The research results indicate that, when compared to MLS, the proposed Eff-MLS leads to an average 3.3% reduction in CV, while improving safety excitation efficiency by 442.26% in the simulation model. Similar effects were also observed in in-vivo experiments. Impact: By enhancing RF shim efficiency and reducing the required excitation power while maintaining uniformity, this approach paves the way for more precise, high-resolution cardiac imaging at ultra-high field strengths. The potential impact includes broader applications of ultra-high field CMR.