Yulin V. Chang1, 2, Philip V. Bayly2
1Radiology, Washington University, Saint Louis, MO, United States; 2Mechanical Engineering and Materials Science, Washington University, St. Louis, MO, United States
Most of the phase-based flip angle (FA) or B1 mapping methods are sensitive to the background field (B0) inhomogeneity. In this work we focus on the recently proposed orthogonal-α method and investigate the effect of B0 inhomogeneity on the FA maps. We demonstrate that by acquiring an addition image with only a single RF pulse the FA-map quality can be maintained in the presence of B0 inhomogeneity, provided that the inter-pulse delay is short compared to T2*.