Franz Patzig1, Bertram Wilm1, and Klaas Paul Pruessmann1
1Institut for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
1Institut for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
We demonstrate the capability of coil-arrays to encode temporal information to be utilized to obtain an estimate of the B0 background field and self-correct single-shot images using standard EPI and spirals (up to R=4).
Figure 3. Self-correction of images acquired with single-shot spiral and EPI (R=2) trajectories: blurring and geometrical distortions could be effectively mitigated. The algorithm was initialized with no information on B0 given. Overlays of the self-corrected and the uncorrected images show vast differences. The corrected images show only minor differences to the reference images and in some areas even more details in the spiral images. The estimated field maps are similar for spiral and EPI trajectories in both slices.
Figure 5. Single-shot self-correction shown for spiral-out and EPI read-outs for varying undersampling factors. In the fully sampled cases field maps with 15x15 coefficients were fitted; in the undersampled scenarios (R=2-4) maps modelled with 13x13 coefficients were fitted to increase the regularization. B0-introduced blurring and geometrical distortions in spirals and EPIs (lines added for assistance), respectively, could effectively be reduced without requiring any prior knowledge on B0.
