sigpy.mri.rf.trajgrad.epi

sigpy.mri.rf.trajgrad.epi(fov, n, etl, dt, gamp, gslew, offset=0, dirx=-1, diry=1)[source]

Basic EPI single-shot trajectory designer.

Parameters:
  • fov (float) – imaging field of view in cm.
  • n (int) – # of pixels (square). N = etl*nl, where etl = echo-train-len and nl = # leaves (shots). nl default 1.
  • etl (int) – echo train length.
  • dt (float) – sample time in s.
  • gamp (float) – max gradient amplitude in mT/m.
  • gslew (float) – max slew rate in mT/m/ms.
  • offset (int) – used for multi-shot EPI goes from 0 to #shots-1
  • dirx (int) – x direction of EPI -1 left to right, 1 right to left
  • diry (int) – y direction of EPI -1 bottom-top, 1 top-bottom
Returns:

(g, k, t, s) tuple containing

  • g - (array): gradient waveform [mT/m]
  • k - (array): exact k-space corresponding to gradient g.
  • time - (array): sampled time
  • s - (array): slew rate [mT/m/ms]
Return type:

tuple

References

From Antonis Matakos’ contrib to Jeff Fessler’s IRT.