ASLSimulator

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

Bases: Simulator

The label-control difference of arterial spin labelling, over time.

The general kinetic model [1]: labelled blood arrives after the arterial transit time ATT, is delivered at the blood flow CBF for the labelling duration, and relaxes with the blood’s T1 before it arrives and with the tissue’s apparent T1, 1 / (1 / T1 + f / lambda), once it has exchanged into tissue. Continuous and pseudo-continuous labelling deliver a bolus of constant concentration; pulsed labelling one whose tail left the labelling slab earlier and has relaxed for longer. The defaults for the blood’s T1, the partition coefficient and the labelling efficiency are the consensus values at 3 T [2].

References

[1]

Buxton, R. B., Frank, L. R., Wong, E. C., et al., “A general kinetic model for quantitative perfusion imaging with arterial spin labeling”, Magnetic Resonance in Medicine 40.3 (1998), pp. 383-396. https://doi.org/10.1002/mrm.1910400308

[2]

Alsop, D. C., Detre, J. A., Golay, X., et al., “Recommended implementation of arterial spin-labeled perfusion MRI for clinical applications”, Magnetic Resonance in Medicine 73.1 (2015), pp. 102-116. https://doi.org/10.1002/mrm.25197

Examples

import torch
from torchsim.simulators import ASLSimulator

sequence = ASLSimulator(t=torch.linspace(0.0, 5000.0, 51), tau=1800.0)
signal = sequence.simulate(CBF=(20.0, 60.0), ATT=1200.0, T1=1400.0)
print(signal.shape)

torch.Size([2, 51])

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.