公开(公告)号：US4751464A

公开(公告)日：1988-06-14

申请号：US45403

申请日：1987-05-04

申请人： James F. Bridges

发明人： James F. Bridges

IPC分类号： H01P7/06 ,  A61B5/055 ,  G01R33/34 ,  G01R33/341 ,  G01R33/343 ,  G01R33/345 ,  G01R33/20

CPC分类号： G01R33/3678 ,  G01R33/343 ,  G01R33/34007

摘要： A cavity resonator suitable for use in a high-speed nuclear magnetic resonance (NMR) imaging device comprises a plurality of transmission lines aligned parallel to a common axis and magnetically coupled to produce an essentially uniform dipole magnetic field perpendicular to the axis. The transmission lines are two conductor lines, with the first conductors being arranged inwardly of a second conductor common to all lines. The common conductor is symmetrically arranged about the axis of the resonator and constitutes a shield to contain the magnetic field within the cavity. The plurality of transmission lines are conductively isolated from each other but spaced in sufficiently close proximity to each to provide for strong mutual magnetic coupling amongst all transmission lines. A single inductive coupling loop may be provided for driving the resonator with a linearly polarized magnetic field and for receiving NMR information from the resonator. The use of a pair of inductive coupling loops spaced 90.degree. about the resonator axis provides a circularly polarized magnetic field within the resonator when the loops are driven in electrical phase quadrature. Two inductive coupling loops for each imaging mode may be provided to eleminate undesirable modes and hence distortion in the NMR image. The common conductor and the longitudinal ends of the resonator are provided with slits designed to allow the changing high-speed gradient magnetic fields to fill the imaging volume fast enough to accomplish high-speed imaging.