Rapid B1 Mapping in the Presence of B0 Variations

Sohae Chung¹, Daniel Kim¹, Elodie Breton¹, Leon Axel¹

Accurate calibration of B₁ field is particularly important at high fields, where large B₁ variations can cause flip angle (FA) variations. The most straight-forward "B₁ mapping" method is the double angle method. However, it is inefficient due to a need to set TR≥5T1. An alternative approach is to perform a series of RF-prepared TurboFLASH imaging. However, both methods directly measure the FA determined by both B₁ and B₀, and require a B₀ measurement to calculate B₁. The purpose of this study was to modify the TurboFLASH imaging to include B₀ correction for rapid B₁ mapping and to evaluate its accuracy.