PRESS-based proton single-voxel spectroscopy and spectroscopic imaging with very short echo times using asymmetric RF pulses.

Modified point-resolved spectroscopy (PRESS) sequences for single voxel spectroscopy (MRS) and spectroscopic imaging (SI) with very short echo time ( T(E)) are described using asymmetric radio-frequency (RF) pulses as well as an optimized design and timing of the PRESS sequence. The proposed sequences were implemented on a standard 4.7 T imaging system yielding a T(E) of 6.0 ms only. Simulations and experimental data measured on phantoms and the rat brain in vivo are presented for MRS and SI showing a high signal-to-noise ratio and hardly any phase distortions caused by J-coupling.