mrpro.operators.models.WASABI

class mrpro.operators.models.WASABI(offsets: Tensor, tp: float | Tensor = 0.005, b1_nom: float | Tensor = 3.7, gamma: float | Tensor = 42.5764, freq: float | Tensor = 127.7292)

Bases: SignalModel[Tensor, Tensor, Tensor, Tensor]

WASABI signal model.

__init__(offsets: Tensor, tp: float | Tensor = 0.005, b1_nom: float | Tensor = 3.7, gamma: float | Tensor = 42.5764, freq: float | Tensor = 127.7292) → None

Initialize WASABI signal model for mapping of B0 and B1 [SCHU2016].

Parameters:

• offsets – frequency offsets [Hz] with shape (offsets, …)

• tp – RF pulse duration [s]

• b1_nom – nominal B1 amplitude [µT]

• gamma – gyromagnetic ratio [MHz/T]

• freq – larmor frequency [MHz]

References

[SCHU2016]

Schuenke P, Zaiss M (2016) Simultaneous mapping of water shift and B1(WASABI)—Application to field-Inhomogeneity correction of CEST MRI data. MRM 77(2). https://doi.org/10.1002/mrm.26133

forward(b0_shift: Tensor, relative_b1: Tensor, c: Tensor, d: Tensor) → tuple[Tensor]

Apply WASABI signal model.

Parameters:

• b0_shift – B0 shift [Hz] with shape (… other, coils, z, y, x)

• relative_b1 – relative B1 amplitude with shape (… other, coils, z, y, x)

• c – additional fit parameter for the signal model with shape (… other, coils, z, y, x)

• d – additional fit parameter for the signal model with shape (… other, coils, z, y, x)

Return type:

signal with shape (offsets … other, coils, z, y, x)