We evaluated the relationship between phase loop and fat suppression using the spectrally selected inversion recovery pulse(Spec IR)technique. The sequence was the three-dimensional fast spoiled gradient echo(3D fast SPGR). The Spec IR technique utilizes a fat-selective inversion recovery pulse in order to suppress fat. When encoding is performed for all slices(phase-slab loop)with one phase encoding, it is necessary to perform slice encoding in a centric. On the other hand, when encoding is performed for all phases(slab-phase loop)with one slice encoding, it is necessary to perform phase encodings in a centric. For the phase-slab loop, an inversion recovery pulse equal to the number of phase encodings is used. For the slab-phase loop, an inversion recovery pulse equal to the number of slices is used. Since relatively few inversion
recovery pulses are used with the slab-phase loop, the signal remains at the fat edge. |
