IhMtPreparation

class pypulseqpp.sequences.IhMtPreparation

Bases: OffResonanceSaturation

Simultaneous dual-offset saturation for ihMT measurements.

Each band receives 1/sqrt(2) of the matched single-offset amplitude. Compare against positive- and negative-offset MtPreparation acquisitions at matched deposited power.

Parameters:

• system (Opts) – System limits.

• flip_angle_deg (float, default=500.0) – Flip angle (degrees) of the single-offset arm this one is matched against. Each band gets 1 / sqrt(2) of it.

• freq_offset_hz (float, default=1500.0) – Distance of each band from water (Hz), positive. Both signs are built.

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

• time_bw_product (float, default=4.0) – Time-bandwidth product of each band.

• 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 dual-band pulse.

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

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

• band_offsets_hz (NDArray[np.float64]) – Where the two bands actually landed (Hz), for a spectral check.

Raises:

ValueError – If freq_offset_hz is not positive 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
>>> ihmt = design.IhMtPreparation(pp.Opts())
>>> ihmt.band_offsets_hz.tolist()
[-1500.0, 1500.0]

Both sidebands at once, with the same total RF power as one band played alone:

(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.