Picker International, Inc.

Other

Nicholas J Mastandrea, Jr

Mark A Richard

Labros S Petropoulos

David A Lampman

A snap-in, whole-body radio frequency coil (38) for increasing the diameter of a bore (12) of a toroidal magnetic resonance imaging apparatus includes a plurality of longitudinally extending coil elements (42) having element ends (44). The longitudinally extending coil elements are disposed on a flat, flexible, non-conductive plastic sheet (40) which is capable of being rolled and disposed concentricly in an interior diameter of the bore to form a thin-walled, bird-cage type radio frequency coil. Adjacent element ends are connected with a first capacitance C.sub.0 to resonate the coil at a certain frequency. To permit mechanically switching the resonant frequency of the coil, protruding metal contacts (60) are electrically connected to the element ends. An adjustment end ring includes separated metal pads (66) disposed on a non-conducting ring substrate (64). Adjacent metal pads are connected with second capacitances C.sub.1. The diameter of the adjustment end ring is preselected to permit resilient contact with the metal contacts. The adjustment end ring is rotatable to bring the metal pads and thus second capacitances C.sub.1 in electrical contact with the element ends which increases the total capacitance between element ends and adjusts the RF coil to resonate at a lower frequency.

Low-cost, snap-in whole-body RF coil with mechanically switchable

A magnetic resonance imaging apparatus (10) includes a primary magnet assembly for generating a temporarily constant magnetic field through an examination region (20), a gradient coil assembly for inducing magnetic field gradients across the examination region (20), and a radio frequency coil for receiving resonance signals from the examination region. The gradient coil assembly includes a coil carrying member (22) carrying first (44) and second (46) spaced apart gradient coil portions which are physically separated from each other on the coil carrying member to define at least one azimuthally directed gap (48, 50, 52, 54) extending along the coil carrying member between said first and second gradient coil portions. The first and second coil portions are disposed towards opposite top and bottom sides of the examination region and have internal windings therein for generating gradient magnetic field components along at least two mutually orthogonal axes (X, Y) in the examination region.

Octapole magnetic resonance gradient coil system with elongate azimuthal

A magnetic resonance imaging apparatus includes a main field magnet (12) for generating a temporally constant magnetic field through an examination region. A radio frequency transmitter (84) excites and manipulates magnetic resonance in selected dipoles in the examination region. A receiver (90) demodulates magnetic resonance signals received from the examination region, a processor (74) reconstructs the demodulated resonance signals into an image representation. A plurality of fingerprint gradient magnetic field coils (24, 26) induce gradient magnetic fields across the temporally constant magnetic field. Each of the fingerprint gradient coils (24, 26) includes a generally spiral winding (32A-32D) having a first crossectional dimension (H) perpendicular to the temporally constant magnetic field which is at least twice a second crossectional dimension (W) in a direction parallel to the temporally constant magnetic field.

Gradient coils with reduced eddy currents

A trolley cage (58) selectively positions an insert gradient coil (56) along a patient beam (38) of a magnetic resonance apparatus (A). The trolley cage (58) includes a lower cage assembly (62) surrounding a first exterior surface portion of the insert gradient coil (56), an upper cage assembly (60) removably secured to the lower cage assembly (62) and surrounding a second exterior surface portion of the insert gradient coil (56), and a number of wheels (90) secured to the lower cage assembly (62) for permitting the trolley cage (58) to roll along a patient beam (38) extending through an examination region of the magnetic resonance imaging apparatus (A). The trolley cage (58) also includes a number of pneumatic latching mechanisms (92) for locking the trolley cage (58) to the patient beam (38) when the insert gradient coil (56) is positioned at isocenter. An interlock mechanism (96, 110-116) is provided which enables the imaging systems of the magnetic resonance imaging apparatus to operate only when the trolley cage is properly locked to the patient beam.

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Euclid, OH, United States of America

Nicholas J Mastandrea, Jr