METHOD AND APPARATUS TO GENERATE MAGNETIC RESONANCE IMAGE DATA OF AN EXAMINATION SUBJECT

摘要

In the magnetic resonance image data acquisition and apparatus, raw magnetic resonance data are acquired at multiple points along a trajectory in k-space from first and second magnetic resonance echo signals caused by a radio-frequency excitation pulse. The course of the trajectory in k-space is established by adjusting a magnetic field value of a gradient magnetic field. The gradient magnetic field has a field value of a first point in time of the trajectory curve and a subsequently modified and at a layer second point in time, the gradient magnetic field has the same field value as that said first point in time. The second point in time is before or during the acquisition of the raw magnetic resonance data of the first magnetic resonance echo signal. The shift value for the trajectory is determined and the trajectory is shifted according to this shift value, and an image is reconstructed from the shifted raw magnetic resonance data of the trajectory.

主权项

1. A method to generate a magnetic resonance image of an examination subject, comprising:
operating a magnetic resonance data acquisition unit to radiate a radio-frequency (RF) excitation pulse that excites nuclear spins in an examination subject, thereby causing said nuclear spins to emit chronologically successive magnetic resonance echo signals; operating said magnetic resonance data acquisition unit to acquire raw magnetic resonance data from the examination subject, including raw magnetic resonance data of a chronologically first of said magnetic resonance echo signals, during activation of a gradient magnetic field, having a magnetic field value, in said magnetic resonance data acquisition unit; entering said raw magnetic resonance data of said chronologically first of said magnetic resonance echo signals into an electronic memory organized as k-space at a plurality of data entry points along a trajectory in k-space having a trajectory path that is established by said magnetic field value of said gradient magnetic field; operating said magnetic resonance data acquisition unit to activate said gradient magnetic field with a first magnetic field value at a first point in time in said trajectory curve, and subsequently modifying said magnetic field value relative to said first magnetic field value, and at a later second point in time activating said gradient magnetic field with said first magnetic field value, said second point in time being before or during acquisition of said raw magnetic resonance data of said chronologically first of said magnetic resonance echo signals; in a processor having access to said memory, automatically determining a shift value for said trajectory from respective values of said raw magnetic resonance data entered at data entry points along said trajectory; from said processor, shifting said read out points by said shift value along said trajectory, thereby producing shifted raw magnetic resonance data; and in said processor, reconstructing an image of the examination subject from the shifted raw magnetic resonance data, and making the reconstructed image available at an output of the processor as an image data file.