3D stack-of-blades spin echo

3D stack-of-blades spin echo#

Family:

Spin echo

Dimensionality:

3D, slab-selective

Sampling:

PROPELLER in-plane, Cartesian partitions

Readout:

One blade line at one partition per excitation

3D stack-of-blades spin echo: one blade line at one partition per excitation.

Prescription#

pypulseqpp.sequences.se_stack_of_blades3D_sequence()#

3D stack-of-blades spin echo: one blade line at one partition per excitation.

A 90 from the selected excitation, a nonselective 180 between crushers half a TE later, and one frequency-encoded line at the echo. Blades, lines and partitions are chosen and ordered as gre_stack_of_blades3D_sequence chooses them. Acquisitions carry the line as LIN, the blade as SEG and the partition as PAR.

Under partition undersampling the central n_acs_z partitions are acquired in full at every tilt, ahead of the rest, and marked IMA.

Parameters:

  • plot (bool, default=False) – Draw the finished sequence in SeqEyes.

  • test_report (bool, default=False) – Print a report on the finished sequence.

  • write_seq (bool, default=False) – Write the sequence to a .seq file.

  • seq_filename (str, default=None) – Where to write it; <NAME>.seq when omitted.

  • system (pypulseqpp.Opts, default=None) – System limits, held under the application’s MAX_GRAD and MAX_SLEW.

  • fov (float, default=0.22) – Isotropic in-plane field of view (m).

  • n (int, default=128) – In-plane matrix size.

  • fov_z (float, default=0.128) – Field of view along the partitions (m). The slab excited is fov_z thick.

  • n_z (int, default=64) – Number of partitions.

  • te (float | None, default=None) – Echo time (s), excitation centre to echo, with the refocusing pulse at its midpoint. None is as short as possible.

  • tr (float | None, default=0.1) – Repetition time (s), one per excitation. None is as short as possible.

  • readout_bandwidth_hz (float, default=250000.0) – Requested receiver bandwidth (Hz).

  • ry (int, default=1) – Angular undersampling: one blade in every ry of the Nyquist set is played.

  • rz (int, default=1) – Partition undersampling: one partition in every rz is acquired, the centre one among them.

  • partial_fourier_z (float, default=1.0) – Fraction of the partition extent acquired, in [0.75, 1].

  • n_dummy (int, default=0) – Non-acquiring repetitions, at the first blade’s centre line and the centre partition, before the scan.

  • excitation ({'slab', 'nonselective', 'spsp'}, default='slab') – A slab-selective SLR pulse, a hard pulse, or a slab- and water-selective spectral-spatial pulse.

  • partition_angle_shift ({'none', 'golden', 'tiny_golden'}, default='none') – How far each partition turns the blades past the previous one, as PARTITION_SHIFTS names the fractions of a half turn.

  • n_acs_z (int, default=16) – Fully sampled calibration partitions at the centre, acquired at every tilt ahead of the rest when rz > 1.

  • blade_width (int, default=16) – Phase-encode lines per blade, at most n.

Returns:

The designed sequence.

Return type:

pypulseqpp.Sequence

Raises:

ValueError – If excitation or partition_angle_shift is unknown, an undersampling factor is below one, blade_width is outside [1, n], partial_fourier_z is outside [0.75, 1], or the TE or TR is shorter than the pulses and the readout take.

Examples

>>> from pypulseqpp import sequences
>>> seq = sequences.se_stack_of_blades3D_sequence(
...     n=32, n_z=4, blade_width=8, tr=None
... )
>>> seq.check_timing()[0]
True

Designed and drawn#

3D stack-of-blades spin echo

3D stack-of-blades spin echo

See also#

Other spin echo sequences: se2D_sequence, se3D_sequence, se_radial2D_sequence, se_stack_of_stars3D_sequence, se_spiral2D_sequence, se_stack_of_spirals3D_sequence, se_propeller2D_sequence, se_epi_propeller2D_sequence.

The same sampling in another family: gre_stack_of_blades3D_sequence.

Every shipped sequence is listed in the catalogue.