free induction decay


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free in·duc·tion de·cay (FID),

in magnetic resonance imaging, the decay curve that is detected by the receiver coil after the application of an excitation pulse, without additional pulses.

free induction decay

An MRI term for a transient MR signal at the Larmor frequency that decays toward zero at a characteristic time constant of T2, when transverse magnetisation of the spins is produced (e.g., by a 90º radiofrequency pulse).

free in·duc·tion de·cay

(FID) (frē in-dŭk'shŭn dĕ-kā')
magnetic resonance imaging The decay curve that is detected by the radiofrequency coil after the application of an excitation pulse, without additional pulses (free).