Figure 4.
A direct comparison between five simultaneous slices acquired with blipped-spiral and stack-of-spirals trajectories is shown. Both trajectories acquire approximately identical k-space samples and the acquisition times are both around 35 ms. Figures a and b show the blipped-spiral slices without and with the field map based off-resonance correction. Figure c shows the trajectory and d the g-factor maps. Corresponding figures for the stack-of-spirals trajectory are shown in (e-h) respectively. The off-resonance map is shown in i. All of the displayed slices are subject to off-resonance deviations that the field map based reconstruction mitigates to some degree in the blipped-spiral images. The stack-ofspirals acquisition however shows significantly distorted image quality compared to the blipped-spiral and the off-resonance corrected reconstruction is not able to improve the overall image quality. The g-factor values are comparably low for both trajectories.