Fast structural brain imaging using an MDEFT sequence with a FLASH-EPI hybrid readout.

A sequence for the fast acquisition of T1 weighted structural brain images with whole brain coverage and isotropic resolution of 1mm is presented. It is based on MDEFT with a FLASH-EPI hybrid readout. Several techniques for artefact suppression are implemented, like echo time shifting, asymmetric k-space sampling, and navigator echo acquisition. It is shown experimentally that the hybrid MDEFT sequence with a total duration of 8min yields approximately the same signal-to-noise and contrast-to-noise ratios as a 12min standard MDEFT sequence based on a FLASH readout. Further experiments show that echo time shifting suppresses artefacts in the vicinity of the scalp and in areas suffering from field inhomogeneities and that the concept of asymmetric k-space sampling reduces the susceptibility to head movement.