Accelerated Gradient-Recalled Echo, Asymetric Spin-Echo (GREASE-II) for Production of High-Resolution Human T1, T2, & T2* Maps

Daniel Lee Shefchik¹, Andrew Scott Nencka¹, Andrzej Jesmanowicz¹, James S. Hyde¹

The gradient-echo asymmetric spin-echo pulse sequence (GREASE) originally allowed for the production of T2 and/or T2* maps. We have modified GREASE to allow simultaneous mapping of T2, T2*, and T1. This was accomplished by accelerating image acquisition by adding partial k-space and generalized autocalibrating partially parallel acquisition (GRAPPA) methods, and utilizing additional excitation and refocusing pulses. These modifications to the original GREASE pulse sequence allow the acquisition of six images following an excitation pulse, enabling the generation of multi-parametric relaxivity maps.