Spatiospectral Phantom for MRI Acceleration

We used the high-resolution spatiospectral numerical phantom described in (30 (link)) for our simulation study. The phantom has 128 × 128 matrix size and 512 time points sampled at a bandwidth of 1200 Hz, and contains spatial distributions of commonly observed ¹H metabolites (see (30 (link)) for a more detailed description). We generated (k, t)-space measurements from this phantom with or without field inhomogeneity effects introduced through a coregistered in vivo ΔB₀ map according to Eq. [1]. A simulated full data set without the field inhomogeneity effects was used as the gold standard to compare three acceleration methods: (i) SPICE, (ii) low-resolution CSI, and (iii) EPSI (7 (link)). The effect of field inhomogeneity was included for all three schemes, which were set up to have the same acquisition time. Additional noise was added into the simulated EPSI data to account for the SNR difference due to different readout bandwidths. The field inhomogeneity corrected conjugate phase (CP) algorithm (31 ) was used to obtain the CSI and EPSI reconstructions, which are compared with the corresponding SPICE reconstructions.