MRI Method of Hybrid Acquisition in 3D TSE

摘要

A method for accelerating magnetic resonance imaging is proposed. In 3D MRI, the method utilizes two sub-echo-trains in each repetition time for the simultaneous acquisition of two contrasts. The first sub-echo-train is a turbo spin echo train and the second sub-echo-train is a gradient echo train. The method acquires two different contrasts simultaneously in a single acquisition, for example one water image plus one fat image, or one turbo spin echo image plus one susceptibility weighted image.

主权项

1. A magnetic resonance imaging method for the acquisition of two 3-dimensional datasets, where spatial encoding by three mutually orthogonal magnetic field gradients is performed such that signal is readout under a readout-gradient in one spatial direction k1, and spatial encoding in two other spatial directions k2, k3 is performed by applying two phase encoding gradients in the two other spatial directions prior to signal acquisition, wherein data acquisition is performed in a sequential manner such that, at each acquisition step, a signal is acquired under the readout-gradient, but with different combinations of the two phase encoding gradients the method comprising the steps of:
a) applying a single excitation RF pulse followed by multiple refocusing RF pulses in a turbo spin echo train to acquire a first 3-dimensional dataset, wherein, a time interval between an excitation RF pulse and a first refocusing RF pulse is half of a time interval between two adjacent refocusing RF pulses; b) acquiring one k-space readout between two refocusing RF pulses; c) varying phase encoding gradients between each two consecutive refocusing RF pulses to acquire different phase encoding steps; d) introducing a waiting time between two successive turbo spin echo trains for encoding of the first 3-dimensional dataset; e) applying, during the waiting time of step d), one excitation RF pulse followed by a single or multiple k-space readouts in a gradient spin echo train to acquire a second 3-dimensional dataset; f) forming an echo in a center of readout by nulling gradient moments applied after each excitation pulse in a frequency encoding direction; g) repeating steps e) and f) in the gradient spin echo train with varying spatial phase encoding steps; and h) repeating steps a) through g) for simultaneous acquisition of the first and second 3-dimensional datasets using both the turbo spin echo train and the gradient spin echo train by repeated application of a series of RF pulses and gradients comprising the turbo and gradient spin echo trains applied in chronological order in each repetition until all data necessary to reconstruct the first and the second 3-dimensional datasets have been acquired in both of the turbo and gradient spin echo trains.