Effects of Relaxation During RF Pulses on the Signal Intensity of Spoiled Gradient Echo Sequences

Nicolas Boulant¹

We present an analysis of the steady state signal in the presence of relaxation during RF pulses in spoiled gradient echo sequences. It is shown that a minor attenuation of the magnetization vector, of the order of one to some percent, can have dramatic consequences on the measured signal in the short TR/long T1 applications, yielding in some cases a substantial loss of signal at the Ernst angle. Measurements on a phantom at 3 teslas are performed to verify this analysis.