Reduction of Spectral Ghost Artifacts in High-Resolution Echo-Planar Spectroscopic Imaging of Water and Fat Resonances

Echo-planar spectroscopic imaging (EPSI) can be used for fast spectroscopic imaging of water and fat resonances at high resolution to improve structural and functional imaging. Be-cause of the use of oscillating gradients during the free induc-tion decay (FID), spectra obtained with EPSI are often degraded by Nyquist ghost artifacts arising from the inconsistency be-tween the odd and even echoes. The presence of the spectral ghost lines causes errors in the evaluation of the true spectral lines, and this degrades images derived from high-resolution EPSI data. A technique is described for reducing the spectral ghost artifacts in EPSI of water and fat resonances, using echo shift and zero-order phase corrections. These corrections are applied during the data postprocessing. This technique is dem-onstrated with EPSI data acquired from human brains and breasts at 1.5 Tesla and from a water phantom at 4.7 Tesla