A NEW T-2 PREPARATION TECHNIQUE FOR ULTRAFAST GRADIENT-ECHO SEQUENCE

The T-2 contrast in images obtained with driven equilibrium (90(x) deg rees-180(x) degrees-90(x) degrees) prepared ultrafast gradient-echo se quences is compromised by the longitudinal magnetization build-up afte r the second 90(x) degrees pulse, which does not carry T-2 information . This paper describes a new T-2 contrast preparation technique for ul trafast gradient-echo sequence that suppresses the signal arising from the build-up. By dephasing in the preparation and rephasing in the ac quisition of the gradient echoes, the new technique eliminates signals that are not dictated by the T-2 contrast in a driven-equilibrium app roach. Consequently, it generates an image that is essentially T-2-wei ghted. Phantom and in vivo experiments were conducted to validate the technique and to demonstrate its clinical utility. These studies indic ate that the technique works properly and can be used for in vivo stud ies.