Expansion:
Free Induction Decay
Technique:
An initial radiofrequency pulse is applied to spinning protons and tips their vector toward the XY plane. Amplitude of signal is proportional to net vector in XY plane (maximum signal at 90 degree RF pulse). An exponentially decaying signal is then received in the absence of any gradients.
Typical Parameters:
RF pulse: 90 degrees (maximum signal amplitude)
Comments:
| no positional information |
| decay determined by T2 characteristics |
| signal decays exponentially |
Pulse Sequence Diagram:
