SPGRSimulator

class torchsim.simulators.SPGRSimulator(*args, **kwargs)

Bases: Simulator

The spoiled gradient-echo steady state, read at the echo time.

Spoiling leaves no transverse magnetization to carry over, so the steady state is the Ernst expression [1] in closed form and no state machine is run. Fitting T1 to a set of these at different flip angles is DESPOT1 [2].

References

[1]

Ernst, R. R., Anderson, W. A., “Application of Fourier transform spectroscopy to magnetic resonance”, Review of Scientific Instruments 37.1 (1966), pp. 93-102. https://doi.org/10.1063/1.1719961

[2]

Deoni, S. C. L., Rutt, B. K., Peters, T. M., “Rapid combined T1 and T2 mapping using gradient recalled acquisition in the steady state”, Magnetic Resonance in Medicine 49.3 (2003), pp. 515-526. https://doi.org/10.1002/mrm.10407

Examples

from torchsim.simulators import SPGRSimulator

sequence = SPGRSimulator(flip=13.0, TR=10.0, TE=5.0)
signal = sequence.simulate(T1=1000.0, T2star=30.0)

Methods

bind	This simulator with more fixed on it, values or settings alike.
describe	Return the description this protocol plays.
evaluate	Evaluate the closed form, no state machine and no description.
from_description	Return a simulator over a stream someone else assembled.
from_pulseq	Return a simulator over one repetition of a Pulseq sequence.
jacobian	Return the signal and its derivative with respect to diff.
layout	Return the operators of one repetition, in the order they play.
played	Return the protocol as it will be laid out.
repetition_s	Return how long one repetition lasts, given what the layout played.
simulate	Return the recorded signal.

evaluate(properties, **sequence)

Evaluate the closed form, no state machine and no description.