Patent ID: 7323875
Filing Date: 2008-01-29
Classification: G01R

Abstract:
1. A magnetic resonance imaging apparatus comprising: a static magnetic field source having two opposite faces connected by a magnetic return structure, said opposite faces facing each other and being separated by a space configured to receive an examination subject therein; first and second assemblies respectively mounted at said opposite faces, said first and second assemblies each being comprised of a plurality of components with the components in said first assembly being disposed mirror-symmetrically, relative to a plane proceeding through said space, with respect to the components in the second assembly; said components in each of said first and second assemblies comprising, in a sequence from one of said opposite faces toward said plane, a pole plate, a pole piece, gradient coils having an annular exterior, an RF transmission coil, a passive first shimming ring disposed at the annular exterior of said gradient coils, and a passive second shimming ring disposed at said annular exterior of said gradient coils adjacent to said first shimming ring; and said second shimming ring in each of said first and second assemblies being mounted to allow adjustment of a distance of said second shimming ring from the first shimming ring in that assembly.