Velocity selective radiofrequency pulse trains.

The incorporation of velocity-encoding gradient pulses in RF-pulse trains is proposed and examined. Velocity selective perturbation is shown to be analogous in many respects to the well established use of trains of short RF-pulses for chemical shift selective perturbation. Velocity selective perturbation is viable in a biomedical setting only if additional RF refocusing pulses are inserted between the individual RF-pulse elements. Aspects of velocity selective excitation saturation and inversion are examined, and new inversion pulse trains proposed. The selective perturbation of both flowing and stationary spins is demonstrated in phantoms and possible biomedical applications of these pulse trains are discussed. Copyright 1999 Academic Press.