Abstract: A method and apparatus for reducing vibration-related artifacts in diffusion weighted imaging determines a vibrational frequency of an MR system and modifies scan parameters such that vibrational frequencies induced on the MR system are inconsistent with the vibrational frequency of the MR system. The method and apparatus improves image quality of MR images acquired using diffusion weighted imaging techniques with the MR system. As such, modification and/or redesign of the MR system to reduce vibrational frequency interaction is reduced.

Abstract: A method and apparatus for reducing vibration-related artifacts in diffusion weighted imaging determines a vibrational frequency of an MR system and modifies scan parameters such that vibrational frequencies induced on the MR system are inconsistent with the vibrational frequency of the MR system. The method and apparatus improves image quality of MR images acquired using diffusion weighted imaging techniques with the MR system. As such, modification and/or redesign of the MR system to reduce vibrational frequency interaction is reduced.

Abstract: A method and apparatus for reducing vibration-related artifacts in diffusion weighted imaging determines a vibrational frequency of an MR system and modifies scan parameters such that vibrational frequencies induced on the MR system are inconsistent with the vibrational frequency of the MR system. The method and apparatus improves image quality of MR images acquired using diffusion weighted imaging techniques with the MR system. As such, modification and/or redesign of the MR system to reduce vibrational frequency interaction is reduced.

Abstract: A mechanical stabilizer-tuned damper is attachable to the first upper magnet assembly of a high field open magnet, which magnet includes a first upper magnet assembly, a lower second magnet assembly and at least one non-magnetizable support beam therebetween. The mechanical stabilizer-tuned damper reduces the dynamic response of the magnet. A connecting device is provided which consists of a threaded rod mounted to an attachment bracket through a linear bearing and vibration mount. A series of non-magnetic and extremely low conductivity plates of various weights are attachable to the rod to change the mass and the tuning frequency of the damper. The location and size of the mechanical stabilizer-tuned damper are determined to balance the frequency of the field oscillation and physical room. The direction of orientation depends upon the direction of motion to be dampened or controlled.

Abstract: An apparatus for supporting a patient support bridge member in an MR system where a first end of the bridge is supported by an upright support member on a first side of an MR imaging bore and the bridge extends through the bore so that a second end of the bridge extends out a second side of the bore, the apparatus including a bracket mounted to an MR main magnet on the second side of the bore and extending upwardly to contact and support the bridge there above.

Abstract: Apparatus is provided for reducing the level of acoustic noise or energy which is received by an imaging subject located within the bore of an MR imaging system. The apparatus comprises a bridge fixed within the bore to support the subject during MR data acquisition, and further comprises a curved frame, usefully formed of fiberglass, which is removably insertable in the bore for placement upon the bridge. The frame, when in place upon the bridge, defines a space within the bore which is disposed to receive the imaging subject. The frame is covered by a layer of material, such as open cell foam, which is capable of absorbing substantial amounts of acoustic energy present in the bore. At the same time, the material is highly transmissive to RF signals required for MR data acquisition and avoids spurious RF signal generation which would add noise to MR data.

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: A secure and stable mounting system for High Field Open (HFO) magnets. A stainless steel mounting plate is secured to the RF screen room floor and the HFO magnet is secured to the mounting plate. Metal angle members are welded around the perimeter edges of the steel plate, and brass wool is inserted between the angle members and the copper sheeting on the floor of the screen room. The invention minimizes magnet motion and thus reduces the risk of image phase ghosting. The invention also provides RF screen room integrity.

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: In an MR system, a mounting assembly is provided at each end of the bore of the main magnet for supporting a cylindrical gradient coil assembly within the bore. Each mounting assembly comprises first and second brackets, the first bracket being provided with a concave bearing surface having a specified curvature. The first bracket is fixably joined to the main magnet proximate to the lower side of the bore, and the second bracket is provided with a convex bearing surface which is selectively similar to the curvature of the concave bearing surface of the first bracket. The second bracket is attached to a lower portion of the gradient coil, so that the convex bearing surface extends longitudinally outward from the gradient coil assembly. A vibration attenuator is positioned between the convex and concave bearing surfaces of each mounting assembly, the vibration attenuator acting to transmit a static force between the two bearing surfaces to support the gradient coil assembly within the bore.

Abstract: An arrangement is provided for supporting the inner and outer gradient coils of one or more gradient coil sets, the coils of each gradient coil set providing one of the orthogonal gradient magnetic fields for an MR imaging system. The arrangement includes an inner cylindrical coil form disposed to supportably carry an inner gradient coil of a coil set, an outer cylindrical coil form in coaxial spaced-apart relationship with the inner coil form disposed to supportably carry an outer gradient coil of the coil set, and a stiffening cylinder positioned between the inner and outer coil forms to divide the space therebetween into first and second volumes. A thermally conductive adhesive material, such as an epoxy containing alumina particulate material, is inserted into the first and second volumes to bond both the inner and outer coil forms to the stiffening cylinder, in order to hold the inner and outer gradient coils respectively carried by the coil forms in rigid fixed relationship with respect to one another.

Abstract: A probe for measuring the displacement between the outer supporting wall of a cryostat and the inner magnet coil form employs magnetically balanced strain gauges attached to a beam with one end fixed to the cryostat wall and the other end held by the magnet coil form. The magnetically balanced strain gauges comprise two superimposed strain gauges with countervailing current flow. In one embodiment, two sets of gauges are attached in conventional bridge arrangement to provide temperature compensation.