Patent ID: 8536870

Claim:
A portable in-bore shim coil insert suitable for correcting high-degree and high-order magnetic field inhomogeneities over a limited examination zone in a magnetic resonance assembly operating at about 3 T-12 T magnetic field strengths and for producing a more homogenous main magnetic (B 0 ) field within the limited examination zone for examination of a targeted Region Of Interest in a chosen subject, wherein the magnetic resonance assembly includes at least a MRI magnet having an internal bore of known configuration and volume, at least one set of gradient coils, and an arrangement of radio frequency coils, said portable in-bore shim coil insert comprising: a movable at will cylinder-like chamber which (i) can be tangibly sited at any location within the bore volume of the MRI magnet in the magnetic resonance assembly, (ii) is a hollow housing having at least one open end and formed solely of non-magnetic materials, and (iii) has fixed length and girth dimensions, and an encompassing perimeter wall with discrete perimeter wall surfaces, and (iv) has a limited examination zone present as a demarcated internal shimming space sized to accept and hold a targeted Region Of Interest of a chosen subject for magnetic resonance examination; at least one shim coil array disposed upon an encompassing wall surface of said cylinder-like chamber, wherein said shim coil array comprises a plurality of surface coils which (α) are disposed in azimuthal symmetry and axial distribution upon a perimeter wall surface and (β) are able to provide multiple supplementary magnetic field gradients on-demand sufficient to cancel substantially at least some high order, high degree inhomogeneities of the B z vector component of the main magnetic (B 0 ) field then present within said demarcated internal shimming space of said cylinder-like chamber; an electrical power supply in communication with said shim coil array; and means for securing said cylinder-like chamber at a selected location within the bore volume of a MRI magnet in the magnetic resonance assembly.