| 摘要 |
The present invention relates to magnetic contrast structures for magnetic resonance imaging, and methods of their use. The contrast structures include magnetic materials arranged as a pair of disk-shaped magnetic components with a space between a circular surface of each disk shape, or a tubular magnetic structure, a substantially cylindrical magnetic structure, a substantially spherical shell-formed magnetic structure, or a substantially ellipsoidal shell-formed structure, each defining a hollow region therein. The space and/or hollow region in the contrast structure creates a spatially extended region contained within a near-field region of the contrast structure over which an applied magnetic field results in a homogeneous field, such that nuclear magnetic moments of a second material when arranged within said spatially extended region precess at a characteristic Larmor frequency, whereby the contrast structure is adapted to emit a characteristic magnetic resonance signal of the magnetic material. |
