Regional Saturation Bands
Regional saturation employs a 90° RF pulse which, when combined with a gradient orthogonal to the imaging plane, affects only a part of the field-of-view. If imaging follows immediately, no signal will be returned from the suppressed region, since there is no longitudinal magnetisation available to receive the RF excitation pulse. It can be used: to suppress fat within regions of images where the fat signal obscures a tissue of interest; to mitigate aliased signals into a region-of-interest; to reduce the effects of chemical shift displacement of signal in volume selection; or to define the region of interest itself by suppressing surrounding signals (especially in MR spectroscopy). The saturation bands are called REST slabs (REgional Saturation Technique), Presat or SAT bands.
