# Spin echoes

One excitation and one refocusing pulse per repetition, with the acquisition
centred on the spin echo. The readout trajectories are those of the gradient
echoes, with a refocusing pulse between the excitation and the readout.

| Example | Scope |
| --- | --- |
| {doc}`/generated/gallery/11-spin-echo/se2D_sequence` | One phase-encode line per excitation. |
| {doc}`/generated/gallery/11-spin-echo/se3D_sequence` | One (line, partition) view per excitation. |
| {doc}`/generated/gallery/11-spin-echo/se_radial2D_sequence` | One full radial spoke per excitation. |
| {doc}`/generated/gallery/11-spin-echo/se_stack_of_stars3D_sequence` | One spoke at one Cartesian partition per excitation. |
| {doc}`/generated/gallery/11-spin-echo/se_spiral2D_sequence` | One spiral interleaf per excitation. |
| {doc}`/generated/gallery/11-spin-echo/se_stack_of_spirals3D_sequence` | One interleaf at one Cartesian partition per excitation. |
| {doc}`/generated/gallery/11-spin-echo/se_propeller2D_sequence` | One line of one rotating blade per excitation. |
| {doc}`/generated/gallery/11-spin-echo/se_epi_propeller2D_sequence` | One whole blade per excitation, read as an echo-planar train. |
| {doc}`/generated/gallery/11-spin-echo/se_stack_of_blades3D_sequence` | One blade line at one Cartesian partition per excitation. |

```{toctree}
:hidden:

/generated/gallery/11-spin-echo/se2D_sequence
/generated/gallery/11-spin-echo/se3D_sequence
/generated/gallery/11-spin-echo/se_radial2D_sequence
/generated/gallery/11-spin-echo/se_stack_of_stars3D_sequence
/generated/gallery/11-spin-echo/se_spiral2D_sequence
/generated/gallery/11-spin-echo/se_stack_of_spirals3D_sequence
/generated/gallery/11-spin-echo/se_propeller2D_sequence
/generated/gallery/11-spin-echo/se_epi_propeller2D_sequence
/generated/gallery/11-spin-echo/se_stack_of_blades3D_sequence
```