Fourier imaging using rf phase encoding.

Abstract

Fourier imaging methods encode information in the amplitudes and phases of a NMR signal over multiple acquisitions. Several of the techniques that can be used for encoding this information are reviewed and a general theory of phase encoding presented. The discussion is then extended to include encoding as part of the rf excitation sequence. Radiofrequency phase encoding can be obtained using tailored excitation techniques or special-purpose rf field gradient coils, and may be applied prior to excitation or incorporated within the excitation or refocusing pulses. This phase-encoding method may be used for spatial and spectral discrimination, as well as being combined with other methods of image formation. An example of the proposed imaging method is described which enables Fourier imaging of short T2 signals.