initialize_3D_helical_shells

mrinufft.trajectories.trajectory3D.initialize_3D_helical_shells(Nc, Ns, nb_shells, spiral_reduction=1, shell_tilt='intergaps', shot_tilt='uniform')

Initialize 3D trajectories with helical shells.

The implementation follows the proposition from [YRB06] but the idea can be traced back much further [IN95].

Parameters:

• Nc (int) – Number of shots

• Ns (int) – Number of samples per shot

• nb_shells (int) – Number of concentric shells/spheres

• spiral_reduction (float, optional) – Factor used to reduce the automatic spiral length, by default 1

• shell_tilt (str, float, optional) – Angle between consecutive shells along z-axis, by default “intergaps”

• shot_tilt (str, float, optional) – Angle between shots over a shell surface along z-axis, by default “uniform”

Returns:

3D helical shell trajectory

Return type:

array_like

References

[YRB06]

Shu, Yunhong, Stephen J. Riederer, and Matt A. Bernstein. “Three‐dimensional MRI with an undersampled spherical shells trajectory.” Magnetic Resonance in Medicine 56, no. 3 (2006): 553-562.

[IN95]

Irarrazabal, Pablo, and Dwight G. Nishimura. “Fast three dimensional magnetic resonance imaging.” Magnetic Resonance in Medicine 33, no. 5 (1995): 656-662