Comparison Between RF Spoiling Schemes in the Actual Flip-Angle Imaging (AFI) Sequence for Fast B1 Mapping

Vasily L. Yarnykh¹

The Actual Flip-angle Imaging (AFI) method allows fast B1 mapping based on the spoiled steady-state principle. The combination of diffusion-based gradient and RF spoiling mechanisms was recently shown to considerably improve accuracy of this method. Two RF spoiling techniques were proposed for AFI in the literature: a standard phase incrementing scheme with a constant value of the phase increment and a modified scheme with two intermittently applied phase increments dependent on the ratio n=TR2/TR1. This study compares the spoiling behavior of the AFI sequence and accuracy of B1 measurements between the above RF spoiling schemes.