Non-Cartesian trajectories

k-space covered by rotating the readout rather than by displacing it. The sampling is no longer on a lattice, so how densely it is covered and how long the traversal takes are both measured rather than prescribed.

Page	What it establishes
Radial sampling	Spokes in place of phase encodes: the azimuthal gap they leave at the edge of k-space, and what golden-angle ordering changes.
Spiral readout	Which of the amplitude, slew-rate and receiver limits determines the duration of a spiral arm, read off the waveform each design produces.