CRISSCROSS MR-IMAGING - IMPROVED RESOLUTION BY AVERAGING SIGNALS WITHSWAPPED PHASE-ENCODING AXES

At conventional magnetic resonance imaging, the number of phase-encodi ng steps is often chosen to be less than the number of readout samples , resulting in reduced spatial resolution in the phase-encoding direct ion. Signal averaging improves the signal-to-noise ratio of the image but does not affect this asymmetry in resolution. By swapping the phas e- and frequency-encoding directions between excitations and averaging the resultant data sets (''criss-cross'' imaging), equal spatial reso lution can be obtained in both principal directions. Increased spatial resolution can be obtained with this method with no increase in imagi ng time, and the method can potentially be applied in echo-planar and three-dimensional Fourier transform imaging.