METHOD AND MAGNETIC RESONANCE APPARATUS TO ACQUIRE MR DATA AND TO RECONSTRUCT AN MR IMAGE

摘要

In a method to operate a magnetic resonance (MR) system to acquire MR data, an RF excitation pulse is radiated followed by repeated, chronologically sequential implementation of the following steps in order to respectively acquire the MR data of an echo train. A refocusing pulse is radiated, a phase coding gradient is activated, and an additional magnetic field gradient for spatial coding is activated in a direction that is orthogonal to the direction of the phase coding gradient in order to read out the MR data of a k-space line. A k-space line in the k-space center is acquired at a predetermined echo time. A first half of k-space is acquired by entering data into k-space lines of the respective echo train, the data being acquired before the echo time. A second half of k-space is acquired by entering data into k-space lines of the respective echo train, this data having been acquired after the echo time. The k-space lines in the first half of k-space have a first density while the k-space lines in the second half of k-space have a second density that differs from the first density.

主权项

1. A method to acquire magnetic resonance (MR) data, comprising:
operating an MR data acquisition unit to execute (1) and (2) below multiple times in order to acquire MR data and enter said MR data into a memory organized as k-space, comprising a plurality of k-space lines; (1) radiate a radio-frequency (RF) excitation pulse that excites nuclear spins in an examination subject and causes the excited nuclear spins to produce an echo train; (2) acquire signals, representing MR data, of said echo train by repeatedly and chronologically sequentially operating the MR data acquisition unit to (a) radiate a refocusing pulse, (b) activate a phase coding gradient, and (c) activate an additional magnetic field gradient that spatially encodes said signals in a direction that is orthogonal to a direction of said phase coding gradient and, during activation of said additional magnetic field gradient, reading out said signals and entering MR data corresponding to said signals into a respective line of k-space; via a processor, controlling entry of the MR data into said memory organized as k-space by entering said MR data into respective lines of k-space, including entering MR data into a k-space line in a center of k-space at a predetermined echo time, entering MR data of a respective echo train acquired before said echo time into k-space lines of a first half of k-space, entering MR data of the respective echo train acquired after said echo time into k-space lines in a second half of k-space, said k-space lines in said first half of k-space having a first density and said k-space lines in said second half of k-space having a second density that is different from said first density; and making the MR data entered into said lines of k-space available in electronic form at an output of said processor.