Reproducibility of Semi-LASER Localized Correlated Spectroscopic Imaging Using Concentric Ring Echo-Planar Trajectories

Five-dimensional correlated spectroscopic imaging using concentric ring trajectories (5D COSI-CONCEPT) has been implemented. Since the maximum slew rates required for the concentric ring trajectories are lower than those for Cartesian echo-planar spectroscopic imaging for a given spectral bandwidth and spatial resolution, the eddy current issues are less challenging. The acquired 5D COSI-CONCEPT data was regridded along k_x-k_y and the accelerated k_z-t₁ data was reconstructed using group sparsity. Reproducibility of the sequence was evaluated in a brain phantom using 3T Prisma and Skyra MRI scanners. Pilot findings showed excellent coefficients of variance and intra-class correlation coefficients for all the six metabolites.