Theoretical models for the acquisition of pulsed ASL data.

See Buxton etal. (1998) for more details.

```
asl2p(beta, TI, T1b = 1.3, T1 = 1, tau = 1, alpha = 0.9, lambda = 0.9,
Mob = 4095)
asl3p(beta, TI, T1b = 1.3, T1 = 1, alpha = 0.9, lambda = 0.9,
Mob = 100)
```

## Arguments

beta |
is a vector (lenth = 2 or 3) of kinetic parameters. |

TI |
is a vector of inversion times (TIs) in seconds. |

T1b |
is the longitudinal relaxation time of blood. |

T1 |
is the longitudinal relaxation time of tissue. |

tau |
is the first TI in the second paper (?). |

alpha |
is the fraction of maximum possible change in the longitudinal
magnetization that was achieved. |

lambda |
is the equilibrium tissue/blood partition coefficient of
water. |

Mob |
is the equilibrium magnetization of arterial blood. |

## Value

A theoretical curve of pulsed ASL signal as a function of time.

## Author

Brandon Whitcher bjw34032@users.sourceforge.net

## References

Buxton, R.B., Frank, L.R., Wong, E.C., Siewert, B., Warach, S.
and Edelman, R.R. (1998) A General Kinetic Model for Quantitative Perfusion
Imaging with Arterial Spin Labeling, *Magnetic Resonance in Medicine*,
**40**, 383-396.

## Examples

```
TI <- seq(0, 3, length=256)
beta <- c(f=0.8, deltaT=0.5)
plot(TI, asl2p(beta, TI), type="l", lwd=2,
xlab="Time (sec)", ylab="Signal", main="Pulsed ASL: Standard Model")
abline(v=1.5, lwd=2, col=2)
```