sigpy.mri.rf.adiabatic.bir4¶
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sigpy.mri.rf.adiabatic.
bir4
(n, beta, kappa, theta, dw0)[source]¶ Design a BIR-4 adiabatic pulse.
BIR-4 is equivalent to two BIR-1 pulses back-to-back.
Parameters: - n (int) – number of samples (should be a multiple of 4).
- beta (float) – AM waveform parameter.
- kappa (float) – FM waveform parameter.
- theta (float) – flip angle in radians.
- dw0 – FM waveform scaling (radians/s).
Returns: 2-element tuple containing
- a (array): AM waveform.
- om (array): FM waveform (radians/s).
References
Staewen, R.S. et al. (1990). ‘3-D FLASH Imaging using a single surface coil and a new adiabatic pulse, BIR-4’. Invest. Radiology, 25:559-567.