A novel method for fast and high-resolution metabolic imaging, called
ECcentric Circle ENcoding TRajectorIes for Compressed sensing (ECCENTRIC), has
been developed and implemented on 7 Tesla human MRI. ECCENTRIC is a
non-Cartesian spatial-spectral encoding method optimized for random
undersampling of magnetic resonance spectroscopic imaging (MRSI) at ultra-high
field. The approach provides flexible and random (k,t) sampling without
temporal interleaving to improve spatial response function and spectral
quality. ECCENTRIC needs low gradient amplitudes and slew-rates that reduces
electrical, mechanical and thermal stress of the scanner hardware, and is
robust to timing imperfection and eddy-current delays. Combined with a
model-based low-rank reconstruction, this approach enables simultaneous imaging
of up to 14 metabolites over the whole-brain at 2-3mm isotropic resolution in
4-10 minutes with high signal-to-noise ratio. In 20 healthy volunteers and 20
glioma patients ECCENTRIC demonstrated unprecedented mapping of fine structural
details of metabolism in healthy brains and an extended metabolic
fingerprinting of glioma tumors.Comment: 20 pages, 7 figures,2 tables, 10 pages supplementary materia