Method for reducing artifacts in image data reconstructed from measurement data of an object under examination captured using an echo-planar acquisition technique (EPI)

A magnetic resonance system, comprising:

• a magnet unit;
• and
• a control device configured to reduce artifacts in image data reconstructed from measurement data of an object under examination captured using an echo-planar acquisition technique by:
• loading measurement data that was generated by:
• generating a train of at least two echo signals from at least one slice of the object under examination, in each case, after an RF excitation pulse;
• capturing the echo signals while switching read-out gradients with alternating polarity for successive echo signals;
• and
• acquiring the captured echo signals as the measurement data;
• capturing, for the at least one slice of the object under examination, a first set of reference measurement data for reducing artifacts using a gradient echo (GRE) acquisition technique,
• wherein the first set of reference measurement data is captured after a plurality of excitations with different phase encoding and, in each case, while switching identically configured read-out gradients having a first polarity;
• capturing, for the at least one slice of the object under examination, a second set of reference measurement data for reducing artifacts using the GRE acquisition technique,
• wherein the second set of reference measurement data is captured after a plurality of excitations with different phase encoding and, in each case, while switching identically configured read-out gradients having a second polarity differing from the first polarity;
• determining first and second calibration data based upon the captured first and second sets of reference measurement data, respectively;
• applying the first calibration data and the second calibration data in the course of a dual-polarity GRAPPA (DPG) algorithm to correct artifacts in the image data reconstructed from the measurement data caused by errors in the measurement data by to generate corrected image data.

A non-transitory computer-readable medium having instructions stored thereon that, when executed by a control device of a magnetic resonance system, cause the magnetic resonance system to reduce artifacts in image data reconstructed from measurement data of an object under examination captured using an echo-planar acquisition technique by:

• loading measurement data that was generated by:
• generating a train of at least two echo signals from at least one slice of the object under examination, in each case, after an RF excitation pulse;
• capturing the echo signals while switching read-out gradients with alternating polarity for successive echo signals;
• and
• acquiring the captured echo signals as the measurement data;
• capturing, for the at least one slice of the object under examination, a first set of reference measurement data for reducing artifacts using a gradient echo (GRE) acquisition technique,
• wherein the first set of reference measurement data is captured after a plurality of excitations with different phase encoding and, in each case, while switching identically configured read-out gradients having a first polarity;
• capturing, for the at least one slice of the object under examination, a second set of reference measurement data for reducing artifacts using the GRE acquisition technique,
• wherein the second set of reference measurement data is captured after a plurality of excitations with different phase encoding and, in each case, while switching identically configured read-out gradients having a second polarity differing from the first polarity;
• determining first and second calibration data based upon the captured first and second sets of reference measurement data, respectively;
• applying the first calibration data and the second calibration data in the course of a dual-polarity GRAPPA (DPG) algorithm to correct artifacts in the image data reconstructed from the measurement data caused by errors in the measurement data by to generate corrected image data.