Pulse sequence

down angle photography of red clouds and blue sky
  • Series of RF pulses, gradients and intervening time periods
  • Time period determines image weighting
  • Sequence is needed to produce signals sufficient enough to form an image
  • Changing TE and TR enables forming different types of contrast
  • Spins are rephased using
    • 180 degree RF pulse – conventional spin echo, fast or turbo spin echo, inversion recovery, STIR, FLAIR
    • Gradient –  coherent gradient echo, incoherent gradient echo, steady-state free precession, balanced gradient echo, EPI