Fig. 1.

DESS sequence diagram showing two repetitions. Two echoes are acquired per TR with all gradients rewound except a non-rewound spoiler component (shaded), which is combined with dephaser/rephaser gradients if played on Gx. The spoiler gradients provide diffusion weighting because moving spins will experience different gradients before and after the refocusing RF pulse. The differences in gradient history will cause imperfect rephasing, resulting in signal loss.