Abstract: A system and method including an apparatus for use in electrically loading RF coils of an MRI system is disclosed. The apparatus includes a polymer interdispersed with an electrically conductive additive such that the apparatus provides the necessary electrical loading of the RF coils for testing and calibration of the MRI system but is free of liquid. Furthermore, the apparatus is capable of providing the requisite electrical load in high magnet magnetic fields without introducing image distortion as a result of standing waves within the apparatus.

Abstract: A system and method including an apparatus for use in electrically loading RF coils of an MRI system is disclosed. The apparatus includes a polymer interdispersed with an electrically conductive additive such that the apparatus provides the necessary electrical loading of the RF coils for testing and calibration of the MRI system but is free of liquid. Furthermore, the apparatus is capable of providing the requisite electrical load in high magnet magnetic fields without introducing image distortion as a result of standing waves within the apparatus.

Abstract: A magnetic resonance imaging device has a compensation circuit for compensating for magnetic disturbances therein. The compensation circuit includes a sensor for sensing magnetic field changes and generating a magnetic field change signal. The sensor is coupled to a control circuit that has a transfer function therein. The control circuit is used to generate a compensation signal in response to the magnetic field change signal. The compensation signal may be coupled to the compensation coils located by the first magnet portion and the second magnet portion of the device. Also, the compensation signal may produce a time-dependent bias or change the center frequency to cancel magnetic disturbances.

Abstract: Apparatus which provides a barrier for vibrational energy between an MR imaging system and an associated horizontal support surface includes a stiff platform of substantial mass, which is disposed to carry the entire weight of the MR imaging system. The apparatus further includes a number of vibration isolation elements positioned to support the platform and the MR imaging system upon the horizontal support surface. Each of the isolation elements comprises an enclosure containing pressurized air which is disposed to dampen vibrations, in order to oppose the transmission of vibrations between the platform and the support surface. An air pressure regulator is coupled to respective isolation elements to maintain specified air pressure levels therein, in order to support the platform in selected spaced-apart orientation with respect to the horizontal support surface.

Abstract: In an MR imaging system provided with a main magnet having a bore and with a gradient coil assembly located within the bore, RF coil apparatus is provided for reducing noise in the imaging volume of the MR system. The RF coil apparatus comprises a tubular RF coil form provided with an inner surface, an RF coil attached to the inner surface of the RF coil form, and mounting structure extending between the RF coil form and gradient coil assembly. The mounting structure supports the RF coil and RF coil form upon the gradient coil assembly, in spaced-apart relationship therewith. The apparatus further compises an inner tubular member which is selectively constructed to oppose transmission of acoustic signals from the RF coil to the imaging volume.

Abstract: Vibration and noise isolation for a magnetic resonance imager (MRI) superconducting magnet cryocooler includes a bellows between the cryocooler and its vacuum sleeve in the magnet, a mass suspended along the axis of, but at a distance from, the cryocooler, elastomeric blocks parallel to the axis, and braided copper wires connecting the vacuum sleeve and the heat shields of the MRI. Motion limiters and bellows flexures are provided for dynamic loads which might be encountered during transport of the magnet.