Single-Shot Magnetic Resonance Spectroscopic Imaging

A magnetic resonance spectroscopic imaging (MRSI) pulse se-quence based on proton–echo-planar-spectroscopic-imaging (PEPSI) is introduced that measures two-dimensional metabo-lite maps in a single excitation. Echo-planar spatial–spectral encoding was combined with interleaved phase encoding and parallel imaging using SENSE to reconstruct absorption mode spectra. The symmetrical k-space trajectory compensates phase errors due to convolution of spatial and spectral encod-ing. Single-shot MRSI at short TE was evaluated in phantoms and in vivo on a 3-T whole-body scanner equipped with a 12-channel array coil. Four-step interleaved phase encoding and fourfold SENSE acceleration were used to encode a 16 16 spatial matrix with a 390-Hz spectral width. Comparison with conventional PEPSI and PEPSI with fourfold SENSE accelera-tion demonstrated comparable sensitivity per unit time whe