3D Imaging: MP-RAGE

Abstract

The challenge of extending TurboFLASH (FSPGR, TFE) from a 2D to a 3D acquisition is due to the fact that the effect of an inversion pulse applied at the very beginning of the acquisition is lost during the acquisition. This is due to the high number of excitation pulses and the relatively long measurement time associated with 3D acquisitions. This may be overcome by repeating the inversion pulse during the measurement, an approach called magnetization-prepared rapid gradient echo (MP-RAGE). Three-dimensional image acquisition requires a repetition of all phase encoding steps in the slab (partition) direction for every phase encoding step within the imaging plane. The inversion pulse is thus placed just prior to the partition encoding loop (in most cases). Within the partition encoding loop, the signal is changing due to recovery of the longitudinal magnetization.