Echo-planar high-resolution flow velocity mapping.

A technique for the very rapid measurement of blood flow with high spatial resolution is described. The method combines the previously validated technique of phase velocity mapping and echo-planar principles. The relatively small diameter of blood vessels enables a high-resolution echo-planar flow measurement to be made with as few as 16 echoes such that the method can be incorporated into a near standard NMR scanner. Two sequence variations are tested and validated in vitro and one is used to demonstrate in vivo blood flow measurement. The results are shown to compare well with a previously validated less rapid method. The technique should enhance the potential of NMR flow imaging by enabling sudden changes in flow to be studied. It should also simplify the measurement of blood flow in small mobile vessels such as the coronary arteries.