A Fast Spin-Echo Multi Gradient-Echo Sequence to Reduce Distortions on T2-Weighted Images at High Field

Ludovic de Rochefort¹, Martine Guillermier¹, Diane Houitte¹, Marion Chaigneau¹, Philippe Hantraye¹, Vincent Lebon¹

Susceptibility-induced magnetic field and chemical shift increase image distortion at high field. In a 2D FSE sequence, increasing the bandwidth to limit these artifacts implies degrading SNR by reducing the ratio of the observation time (TO) per unit time rapidly reaching SAR and gradient duty cycle limitations. We propose to replace the readout within the 180 pulses by a train of gradient echoes with a larger bandwidth and the same TO. It is shown in vivo on rat brain that susceptibility induced distortions are suppressed by this approach while preserving SNR and contrast.