In-room imaging and MR planning

Flow artifacts

TE

phase

• Gradients are used for spatial encoding • In this set-up for stationary spins, the phase shift after the first gradient lobe, will be reversed exactly at echo time • However, if spins move, the phase will get distorted • Because of the pulsatile character, this distortion will be different for each repetition (i.e. phase-encoding step). Thus, in the phase-encoding direction you will see displacements of the blood signal