MtPreparation

class pypulseqpp.sequences.MtPreparation

Bases: OffResonanceSaturation

Off-resonance SLR saturation followed by an optional spoiler.

Parameters:

• system (Opts) – System limits.

• flip_angle_deg (float, default=500.0) – Nominal flip angle (degrees). Far above 90: the point is deposited power, not a tip.

• freq_offset_hz (float, default=-1500.0) – Offset from water (Hz); must not be zero.

• duration_s (float, default=0.008) – Pulse duration (s).

• time_bw_product (float, default=4.0) – Time-bandwidth product, which with duration_s sets how wide a band of the bound pool is saturated.

• n_pulses (int, default=1) – Pulses in the train.

• spoiling_cycles (float, default=4.0) – Dephasing of the final spoiler, in cycles across voxel_size_m. Zero omits the spoiler, as required for a pulse used for its phase effect rather than for saturation.

• voxel_size_m (float, default=0.001) – Length the dephasing is counted over (m).

• labels (Sequence[str], default=None) – Counters emitted on the first pulse’s block.

Attributes:

• rf_prep (RfEvent) – The pulse, published once however many times it is played.

• gx_spoil, gy_spoil, gz_spoil (GradEvent) – The closing spoiler, when there is one.

• prep_labels (LabelEvent | list[LabelEvent]) – One per name in labels.

Raises:

ValueError – If freq_offset_hz is zero or a duration is not positive. If n_pulses is below one, or a spoiling argument is out of range.

Examples

>>> import pypulseqpp.sequences as design
>>> import pypulseqpp as pp
>>> mt = design.MtPreparation(pp.Opts())
>>> len(mt.blocks), round(float(mt.rf_prep.freq_offset))
(2, -1500)

One band below resonance, with the free pool at zero offset not directly saturated:

(svg)

(svg)

Methods

init_module	Build the module's block layout; implemented by the subclass.
publish	Publish events from the caller's locals and register keyword aliases.
register	Publish named events without requiring prior block registration.
sim_rf	Simulate this module's pulse across off-resonance.

Attributes

blocks	Return block tuples in play order, retaining the original event objects.
duration	Duration of the module in seconds.
seq	Sequence holding the module's construction-time block layout.