make_b1_selective_pulse

make_b1_selective_pulse#

pypulseqpp.make_b1_selective_pulse()[source]#

Design a B1-selective RF pulse, excited only where the transmit amplitude lies in a band.

Constant-magnitude RF whose frequency is swept: in the frame tilted onto the RF field, the local B1 plays the part of a gradient and the sweep that of the RF, so the selection is along B1 rather than along space (Grissom, Cao and Does, J Magn Reson 242:189, 2014). No gradient is played.

Parameters not listed below are as in make_slr_pulse().

Parameters:

  • amplitude (float) – RF amplitude the pulse plays at, in T: where B1 is nominal.

  • passband_center (float, default=1.0) – The band of B1 selected, relative to amplitude. The pulse lasts about twice time_bw_product over the width in Hz.

  • passband_width (float, default=0.2) – The band of B1 selected, relative to amplitude. The pulse lasts about twice time_bw_product over the width in Hz.

  • pulse_type ({'st', 'ex', 'se', 'inv', 'sat'}, default='st') – Only maps the ripples onto the filter, as in make_slr_pulse(); the flip is flip_angle.

  • split_and_reflect (bool, default=True) – Split the sweep and reflect it about the pulse’s centre, which keeps the selectivity at large tip.

Returns:

The pulse.

Return type:

RfEvent

Raises:

ValueError – If passband_width is not positive or the passband reaches zero B1.