Direct Encoded Signal Control with Phase Distribution Graphs for readout-tailored multipulse pTx

Motivation: In high-field MR imaging the image quality suffers due to high transmit (B1+) inhomogeneities. Goal(s): The primary goal was to enhance the B1+ shimming process by individually optimizing pulses for improved overall magnetization homogeneity, aiming for better reconstructed image quality without visible inhomogeneities. Approach: This study used Phase Distribution Graphs (PDG) and the MR-zero framework for multi-coil transmit setups, optimizing shimming across each pulse and entire sequence. Results: Simulations and in vivo measurements confirmed that the optimized sequences achieved superior homogeneity and image quality compared to traditional shim modes. Impact: This approach enables more precise RF shimming for high-field MRI, improving image quality. It opens avenues for investigating optimized sequences across various readout strategies, reducing the need for manual tuning, which can enhance clinical and research imaging applications.