Patent ID: 7737693

Claim:
A method for obtaining a magnetic resonance image of at least a portion of an imaging volume, the imaging volume being located within a spatially inhomogeneous static magnetic field that is characterized by non-planar isomagnitude contour surfaces, the method comprising: applying to the imaging volume selective Radio Frequency irradiation, the selective Radio Frequency irradiation being configured so as to selectively excite nuclear spins within at least one spatial zone of the imaging volume, each of the spatial zones being bounded by two of the non-planar isomagnitude contour surfaces that are sufficiently close to each other to ensure that the inhomogeneous static magnetic field contained therebetween has a substantially linear static field gradient; allowing the excited nuclear spins to precess during a plurality of phase encoding time periods so as to encode spatial information into the excited nuclear spins, the spatial information being encoded into each nuclear spin using a magnitude of the linear static field gradient local to the excited nuclear spin, a location of the excited nuclear spin along an axis parallel to a direction of the linear static field gradient at the location of the excited nuclear spin, and a magnitude of an applied magnetic field local to the excited nuclear spin that is produced by at least one external magnetic field gradient applied during at least one of the phase encoding time periods; receiving Radio Frequency signals generated by the excited nuclear spins; computationally processing the received Radio Frequency signals so as to reconstruct an image of the at least one spatial zone, and repeating the above steps for a plurality of spatial zones.