GRAPPA Reconstruction of Sensitivity Encoded 2D and 3D Proton Echo Planar Spectroscopic Imaging (PEPSI) with SNR Adaptive Recalibrating

M. Rueckert, R. Otazo, S. Posse MIND Institute, Albuquerque, New Mexico, United States, Dept. of Physics and Astronomy, University of New Mexico, Albuquerque, New Mexico, United States, Dept. of Electrical and Computer Engineering, University of New Mexico, Albuquerque, New Mexico, United States, Dept. of Psychiatry, University of New Mexico School of Medicine, Albuquerque, New Mexico, United States INTRODUCTION: We recently introduced the accelerated Proton-Echo-Planar-Spectroscopic-Imaging (PEPSI) with SENSE and GRAPPA parallel imaging [1,2]. In this study we demonstrate that 4T PEPSI data with an 8-channel coil array can be reconstructed with up to 4-fold acceleration using GRAPPA algorithm [4]. We show the feasibility of 2D encoding in 16 seconds and 3D spatial encoding in about 2 minutes without significant loss in spectral quality. In addition, we showed that it is crucial to match the SNR level of the reference data used for calibrating GRAPPA to the SNR level of the PEPSI data for optimal GRAPPA reconstruction.