System and method for ultrafast magnetic resonance spectroscopic imaging using learned spectral features

A method of acquiring spatiospectral distributions from an object, the method comprising:

• generating a static magnetic field, the object being positioned in the static magnetic field;
• controlling an RF transceiver to transmit RF signals to an RF coil assembly including a plurality of gradient coils;
• controlling the RF transceiver to receive imaging data;
• acquiring, based upon the imaging data, spatiospectrally encoded free induction decays (FIDs) that sparsely sample a (k,t)-space with ultrashort TE and short TR;
• acquiring, based upon the imaging data, embedded navigator data for tracking system instability and for tracking motion of the object, wherein the navigator data are acquired simultaneously with the spatiospectrally encoded FIDs;
• reconstructing spatiospectral functions from the spatiospectrally encoded FIDs using spectral features learned from training data acquired experimentally and generated using quantum mechanical simulations;
• separating, based upon the imaging data, spatiospectral distributions of water, lipids, metabolites and macromolecules;
• and
• generating one or more quantitative tissue susceptibility maps, one or more T2* maps, one or more B0 inhomogeneity maps, and one or more maps of various metabolites and macromolecules from a single MRSI data set that is based upon the imaging data;
• wherein the ultrashort TE is less than 4 ms and the short TR is less than 300 ms, and wherein the method does not require a water suppression pulse or a lipid suppression pulse for 1H-MRSI.

A non-transitory computer-readable storage device comprising executable instructions which, responsive to being executed by a processor, cause the processor to perform operations, the operations comprising:

• acquiring spatiospectrally encoded FID data covering (k, t)-space in variable density and variable SNR with ultrashort-TE and short-TR, without water and lipid suppression, suitable for image reconstruction using a union-of-subspaces model or a linear combination of low-rank matrix/tensor models;
• and
• reconstructing a spatiospectral function from the spatiospectrally encoded FID data that is sparsely sampled using the union-of-subspaces model or the linear combination of low-rank matrix/tensor models;
• wherein the acquiring of the spatiospectrally encoded FID data is performed utilizing an RF coil assembly including a plurality of gradient coils, and an RF transceiver controlled by a pulse module to transmit RF signals to the RF coil assembly, and
• wherein an ultrashort TE less than 4 ms and a short TR less than 300 ms are utilized and no water suppression pulse is used and no lipid suppression pulse is used.