Imaging in the rotating frame

The basic timing sequence for rotating-frame imaging with 2D spatial resolution in y-and z-directions is illustrated in Fig. 6.3.2 [Houl]. In z-direction the gradient is applied in the LCF. In y-direction it is applied in the RCF. The components of the magnetic field 

2 jHoulj Pulse sequence for 2D Fourier imaging in the rotating frame, in these directions can be written as 

An rf pulse of length ([ and average amplitude B, . in the gradient coil rotates the magnetization in the sample by the space-dependent angle 

The simplest way to obtain a 2D image of the spin density consists of acquiring FID signals for difierent pulse lengths fj. The measured signal. v(t]./2) can then be 

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 

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