Magnetic resonance imaging systems
US6218839A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 24, 1999 |
| Grant date | Apr 17, 2001 |
| Priority date | — |
| Expiry date | May 24, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R33/3875
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A magnetic resonance imaging system comprises a magnet (30) for generating a main magnetic field, a gradient coil (34) to superimpose a linearly varying magnetic field over the main magnetic field, and an RF coil (34) forming part of a transmit/receive system for signals which are used to construct an image. A shimset (32) is positioned between the magnet (30) and the gradient coil (34) to provide magnetic field correction and is constructed so as not to have axial and azimuthal symmetry. This is achieved by providing cutout portions (38) in the shimset (32) which are diametrically opposite each other, similar cutouts (40) being provided in the gradient coil (34) which are aligned with the cutout portions (38). The cutout portions (38, 40) accommodate the shoulders of larger patients, therefore reducing the need to extend the bore size of the magnetic resonance imaging system.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.