Fig. 3.
(a) Compared to the fully sampled trajectory, the designed single-shot variable-density spiral trajectory for each time frame or kz plane enables a 12-fold acquisition acceleration. (b) Prospective 2D undersampling pattern with the incoherent rotations between fast time (the oscillation dimension) and slow time (the fMRI time dimension). (c) 3D undersampled stack-of-spirals providing a 10-fold acceleration with one spiral for the outer kz planes, two spirals for the two central kz planes, and golden-angle rotations between kz planes.