Patent ID: 6362623
Filing Date: 2002-03-26
Classification: G01R

Abstract:
In an MRI apparatus comprising:a magnetic structure defining a space into which a subject is placed for examination, and comprising a magnet: RF coil means for providing an RF signal to said magnetic structure; gradient coil means for providing gradient signals to said magnetic structure; and means for providing an image of said subject from signals received from said subject exposed to said RF signal and said gradient signals; the improvement wherein: said gradient coil means comprises at least one main gradient coil disposed in said magnetic structure adjacent said magnet; and at least one shielding coil disposed between said main gradient coil and said magnet whereat winding densities of said main gradient coil and said shielding coil are highest; and wherein:said magnetic structure comprises: a pair of yokes; a pair of permanent magnets attached to said yokes; a pair of magnetic field conditioning plates disposed on opposite faces of said pair of permanent magnets; and wherein said at least one main gradient coil comprises a pair of main gradient coils disposed on opposite surfaces of said magnetic field conditioning plates.