Rapid, Low power PHIFA CUP B1+ Mapping

Motivation: B1+ maps are crucial for MRI applications at high field strengths, but existing methods are often limited by long acquisition times, high power requirements, or T1 saturation effects. Goal(s): To develop a rapid, low-power, phase-based B1+ mapping method using composite pulses. Approach: A phase-based method is proposed that uses optimized composite pulses to manipulate magnetization and achieve high phase accrual using low power and a 32-channel head coil. Results: Simulations, phantom, and in-vivo studies validate the proposed method. It enables rapid B1+ mapping with 4 mm isotropic resolution for the entire 3D brain in 10 seconds at high field strengths. Impact: The proposed rapid, low-power B1+ mapping method reduces acquisition time and SAR. This improvement enhances its utility in clinical and research settings. Future work aims to extend its application to 7T for pTx applications.