A magnetic resonance imaging method of flow by successive excitation of a moving slice

A new magnetic resonance imaging of flow by a method of successive excitation of a moving slice is presented here. The method, which in general belongs to the class of time-of-flight methods, is based upon selectively changing the frequencies in a sequence of rf pulses in such a way that a selected slice moves through the imaged volume in a preselected direction and velocity, and is repeatedly excited. It is claimed that most of the measured signal is contributed by only those parts of the imaged substance that move with the selected slice. The activation procedure of the flowing spins, which is presented here, enhances the imaging of the flowing matter and reduces the signal from static matter. A specially tailored selective sequence of a rf a-pulses has been developed. During this sequence, a set of rephasing 180° selective rf pulses is applied. At the end of this sequence an additional 180° rf pulse is applied to eliminate redundant signals from the static matter in the last activated slice.