Phase-modulated rotating-frame imaging

There has been little development in the theory of MEM in recent years, however the diversity of applications has increased greatly. Examples include the measurement of rotameric distribution in carbohydrates, peptides,or more generally - in isotropic environments. Other applications include studies of the internal order in liquid crystals, a new attempt at the in vivo application of phase-modulated rotating-frame imaging (PMRFI),- - and a study of amphiphilic molecules in ternary systems. 

The image is obtained directly by 2D Fourier transformation over /j and t2, whereby a phase twist can be avoided as a consequence of amplitude modulation. For 1D rotating-frame imaging the field-gradient rf pulse of variable length tj is broken down into a series of short pulses for acquisition of one data point within each delay between the... 

Fig. 6.3.3 [Hou2] Vector diagrams of magnetization illustrating the principle of phase modulation in rotating-frame imaging for a selected volume element. Following an initial y pulse of length ti with variable flip angle 6, the magnetization is placed into the xz plane (left).

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