Non-Cartesian Imaging on a Head-Only System: Impact and Correction of Higher Order Eddy Currents

Motivation: Image quality from non-Cartesian methods on a head only scanner were severely degraded with artifacts suggesting uncorrected eddy currents, even though 0th and 1st order corrections were used. Goal(s): The aim is to measure and correct for higher order (2nd order, including cross term) eddy currents. Approach: A sequence was developed to measure the eddy currents and an efficient image reconstruction method was develop to account for the non-linear eddy currents. Results: The presence of second order cross-term eddy currents (xz and yz) was confirmed. Image quality was improved with the new reconstruction algorithm. Impact: Non-Cartesian imaging can now be performed on the head only MAGNUS MRI scanner without degradation due to non-linear eddy currents.