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epg_cpmg_echoes

qsm_core::relaxometry

Function epg_cpmg_echoes 

Source 
pub fn epg_cpmg_echoes(
    t2: f64,
    t1: f64,
    b1: f64,
    esp: f64,
    n_echoes: usize,
) -> Vec<f64>
Expand description

Simulate the CPMG multi-echo spin-echo magnitude train.

Models a 90° excitation followed by n_echoes refocusing pulses of nominal 180° scaled by b1 (so the actual refocusing flip is b1 * 180°), spaced by echo spacing esp (seconds). Echoes form at TE_n = n * esp.

§Arguments

  • t2 - Transverse relaxation time (seconds)
  • t1 - Longitudinal relaxation time (seconds)
  • b1 - Refocusing efficiency: fraction of the nominal 180° flip (1.0 = perfect)
  • esp - Echo spacing (seconds)
  • n_echoes - Number of echoes to simulate

§Returns

n_echoes echo magnitudes, normalized so equilibrium magnetization M0 = 1.

With b1 = 1.0 this returns exactly exp(-n * esp / t2) (perfect refocusing).