Ultra-fast imaging technique using k-space segmentation with minimum

Abstract

A plurality of radio frequency excitation pulses or shots (52) are applied, ten in the embodiment illustrated in FIGS. 4 and 5. Following each shot, sets of data lines are collected. In the first set, an early gradient echo (EGE1), a spin echo (SE1), and a late gradient echo (LGE1), are induced to form three corresponding data lines. Magnetization is inverted (56) and a second set of data lines are generated. In the illustrated embodiment, nine sets of data lines are generated in each repetition. Phase-encoding gradient pulses (86, 88) are applied to cause the early gradient echo, the spin echo, and the late gradient echo data lines of each set to fall offset by a third of k-space. Phase-encoding pulses (74) are applied before each set and stepped such that in half of the repetitions, the phase-encoding increases with each subsequent set. In the other half of the repetitions, the phase-encoding decreases for each subsequent set. In this manner, the first and last data line in each segment of k-space are from the same echo position with the repetition. By selecting the intermediate phase-encoding step with which to start the first set, the phase-encoding at the center of k-space is selectively adjustable such that the pseudo echo time is selectively adjustable.