mdreg.spgr_vfa#

mdreg.spgr_vfa(FA, S0, E)[source]#

Signal model for a Variable Flip Angle (VFA) scan.

\[S(\alpha) = S_0 \sin(\alpha) \frac{1 - e^{-T_R/T_1}}{1 - \cos(\alpha) e^{-T_R/T_1}}\]

This function models the MRI signal acquired using a spoiled gradient-echo sequence in the steady-state with different flip angles.

Parameters:

FA (array) – Flip angle \(\alpha\) in degrees.
S0 (float) – Signal scaling factor \(S_0\) in arbitrary units.
E (float) – Exponential fraction \(E = e^{-T_R / T_1}\), where \(T_R\) is the repetition time and \(T_1\) is the longitudinal relaxation time.

Returns:

Signal values at each flip angle.

Return type:

array