3D Variable Flip Angle Fast-Low-Angle-Shot Experiments in the Presence of B1 Inhomogeneity and Slab-Select Gradient

Kelly C. McPhee¹, Stefan A. Reinsberg¹

Variable Flip Angle (VFA) Fast-Low-Angle-Shot (FLASH) experiments are commonly used for T1 and B1 mapping. Due to the effect of non-ideal pulse shape on signal intensities, 3D experiments are often used in place of 2D experiments. We show the effects of this assumption through both simulations and experimental data. The shape of the VFA curve is altered, and a zero-crossing will only be observed in the real part of the signal not in the magnitude of a FLASH VFA curve. We compare T1 and flip angle map results to a VFA experiment with no slab-select-gradient, and find large T1 errors.