Abstract: A two-dimensional projection image of the NMR activity within a volume is obtained. The signals due to static material are not excited and do not appear in the projection image. The signals due to moving blood in vessels produce an isolated image of the vessels with the superimposed structure removed. Excitation systems are used which excite only moving material and return static material to equilibrium.

Abstract: Flyback imaging is combined with echo planar imaging (EPI) for improved readout flow properties. For increases in imaging time of 50% or less, significant improvements in imaging are realized. The partial flyback improves partial-Fourier EPI and inside-out EPI and can be applied to any EPI trajectory.

Abstract: Selective material projection imaging in which static and flowing material are distinguishable utilizes magnetic gradients whose waveforms have selective moments. The effects of the magnetic field gradients are utilized in obtaining data for a plurality of images whereby the subtraction of image data will result in selected material imaging. The zero moment of a magnetic gradient waveform affects the phase of static material and the phase of moving material, while the first moment of a magnetic gradient waveform affects the phase of constant velocity moving material but not the phase of static material. The second moment of a magnetic gradient waveform affects the phase of varying velocity moving material but not the phase of static material or constant velocity material. The nuclear spins of a region of a body can be excited under different conditions of an applied magnetic field gradient so that data under the different conditions can be subtracted to eliminate selected material.

Abstract: A method of imaging material flowing through a slab in a body using magnetic resonance techniques includes placing the body in a magnetic field including a first magnetic (z) gradient for slab thickness selection. A first rf pulse (180.degree.) is applied to the body at a frequency band and of sufficient strength to flip nuclear spins located essentially in the slab. After allowing moving material in the slab to flow from the slab, a second rf (90.degree.) pulse is applied to the body at a frequency band of sufficient strength to flip the nuclear spins in the slab for generating a signal. First image date in an X-Z plane is obtained from the nuclear spins flipped by the second 90.degree. rf pulse. Thereafter, a third 180.degree. rf pulse is applied to the body. In one embodiment the third rf pulse is non-selective and is of sufficient strength to flip nuclear spins in the body including but not limited to the slab. Moving material is again allowed to flow from the slab, and a fourth 90.degree.