Table 1.

Spiral trajectories parameters

	UD	VD-1	VD-2	DD-1	DD-2
Number of arms	3	3	3	3	3
Readout duration per arm (ms)	5.12	5.12	5.12	5.12	5.12
FOV (mm)	340	340	340	340	340
Starting density	0.2	1	0.33	1	1
Ending density	0.2	0.008	0.11	0.18	0.13
Fully sample k-space center (radius)*	N/A	N/A	N/A	20%	20%
Trajectory steepness (τ)*	N/A	N/A	N/A	0.08	0.02
Resolution (mm)	2.05	2.06	2.05	2.05	2.06

^*Fully sampled k-space center and trajectory steepness is only used for dual density trajectories to determine the transition shape from starting density to ending density.