A Simulation Framework for Comparison of Volumetric B1+ Mapping Methods

Motivation: To benefit from all the advantages that ultra-high field MRI offers, knowledge of the RF transmit field (B1+) is required. Many B1+ mapping methods have been developed, but no single method has become the ‘gold-standard’, with many sites opting for their own implementations. Goal(s): To evaluate five promising sequences and understand their sensitivity to B0, T1, flow and SNR on the accuracy and dynamic range of the measured B1+. Approach: SatTFL, Sandwich, SA2RAGE, AFI, and 3DREAM were investigated in MATLAB using open-source EPG and Bloch simulations. Results: A simulation framework to compare B1+ mapping sequences was developed. Impact: This simulation framework is beneficial for understanding the impact of various factors on the accuracy of B1+ mapping sequences and can help to inform better pulse sequence design and parameter optimisation.