Self-Referenced Flip Angle Mapping for Hyperpolarized Gas MRI

Eric Frederick^1,2, Mirko Hrovat³, Samuel Patz²

Hyperpolarized noble gas imaging is a non-equilibrium imaging method where gas magnetization is depleted by RF excitations. Due to B_1 field inhomogeneities, this depolarization may not be uniform and therefore a B_1 flip angle map is required to correct the images. This process is typically performed by acquiring an additional set of images. We propose an alternative method where the flip angle map is obtained from one set of images. To do this, we break up a fully sampled image into two undersampled images that are then used for B_1 flip angle mapping. We demonstrate these methods with simulations.