Abstract: A radio frequency (RF) detector array and a MRI system are provided. The detector array comprises a plurality of conductive array elements being substantially parallel to a conductive ground plane, a plurality of capacitors, wherein at least one capacitor is shunted from each array element to the ground plane to adjust a corresponding electrical length of each conductive array element, and, wherein a combination of each respective array element, at least one corresponding capacitor and the ground plane forms a resonator that resonates at a selected frequency. The detector array further a decoupling interface, and a plurality of matching boxes for matching each decoupled conductive strip to a selected impedance. A MRI system is provided including a detector array as described herein to produce MR images of the object to be imaged.

Abstract: A radio frequency (RF) detector array and a MRI system are provided. The detector array comprises a plurality of conductive array elements being substantially parallel to a conductive ground plane, a plurality of capacitors, wherein at least one capacitor is shunted from each array element to the ground plane to adjust a corresponding electrical length of each conductive array element, and, wherein a combination of each respective array element, at least one corresponding capacitor and the ground plane forms a resonator that resonates at a selected frequency. The detector array further a decoupling interface, and a plurality of matching boxes for matching each decoupled conductive strip to a selected impedance. A MRI system is provided including a detector array as described herein to produce MR images of the object to be imaged.

Abstract: A rotating body coil assembly for use with an open MR magnet for imaging at least a portion of a subject comprises a resonant structure configured to rotate about the subject and to permit access to the subject during imaging. The body coil assembly comprises first and second end ring assemblies positioned on opposing sides of the imaging space. The first and second end ring assemblies are each configured to energize the body coil assembly. A plurality of element assemblies are disposed between and connecting the first and second end ring assemblies for providing structural support and electrical isolation of the body coil assembly. A base assembly is coupled to the first and second end ring assemblies and at least one of the element assemblies.

Abstract: A self-shielded gradient coil assembly for an MR imaging system has inner and outer gradient coil windings disposed in coaxial relationship and defining a hollow annular space therebetween. Inner and outer helical cooling tubes are affixed to the outer and inner surfaces of the inner and outer gradient coil windings, respectively, by a thermally conductive epoxy, and a concrete filler material substantially fills the remaining hollow annular space. The concrete filler material may be poured into the hollow annular space to fill the space, or a pre-formed hollow concrete cylinder may be inserted coaxially into the space, defining remaining inner and outer annular volumes which are then filled with a thermally conductive epoxy bonding together the inner and outer gradient coil windings, the cooling tubes and the hollow concrete cylinder.

Abstract: A quadrature coil suitable for use with an open frame MRI system provides crossing pairs of arrays of parallel conductor elements, respectively. Compact configuration is provided through use of an isolating circuit for incorporating parasitic capacitances at the resonance frequency of the coil into a blocking parallel resonance. Termination of the parallel conductor elements may be accomplished by equal impedance node connectors formed from branching pairs of conductors or a triangular least resistance connection form. RF shields are provided by pairs of conductive sheets containing eddy current reducing slots aligned with the parallel conductors elements of the coil.

Abstract: A low noise imaging apparatus for producing Magnetic Resonance (MR) images of a subject and for substantially minimizing acoustic noise generated during imaging is provided. The imaging apparatus comprises a magnet assembly, a gradient coil assembly, and a rf coil assembly, wherein at least one of the magnet assembly, the gradient coil assembly and the rf coil assembly are configured to reduce the generation and transmission of acoustic noise.

Abstract: An MRI system acquires image data using a spiral pulse sequence in which k-space is sampled in a trajectory comprised of a spiral segment and a symmetric spiral tail segment. The spiral segments partially sample throughout the extent of k-space and the symmetric spiral tail segment samples only in a central region of k-space. The central region of k-space is fully sampled and a phase correction method is used to reconstruct an image from the under-sampled peripheral k-space data set.

Abstract: Accurate sensing of ice readiness in an ice maker is accomplished using, as an ice readiness sensor, a capacitance bridge circuit having a first capacitor connected as a first bridge arm a second capacitor connected as a second bridge arm, a tunable capacitor connected as a third bridge arm and a probe connected as a fourth bridge arm. The probe includes a pair of electrode strips placed in close proximity to the belt of a belt ice maker. First and second bridge arms are connected at a first bridge node first and third bridge arms are connected at a second bridge node, second and fourth bridge arms are connected at a third bridge node, and third and fourth bridge arms are connected at a grounded fourth bridge node. The first and fourth bridge nodes are input terminals for receiving an AC drive signal from an AC source, and the second and third bridge nodes are output terminals.

Abstract: A sweep generator 230 applies a range of frequencies to an rf coil 140 to detect the resonant frequency of a field generated by a magnet 125a,b. A frequency to current converter 220 applies an auxiliary magnetic field to tune an MRI apparatus to the resonant frequency of the rf coil. A flexible coil of one turn (300) or two or more turns (500) has a plurality of segments (301-307; 501-513). One of the belt has a contact k0, (k0′), which is electrically connectable to one or more contacts k1, (k1′), k2, (k2′), etc. located between the ends of the segments. For each connection to successive contacts, the length of the coil and its inductance increases by the added impedance DLij between contacts ki and kj. That increase of inductance is nullified by capacitors DCsij located between segments.

Abstract: An MR magnet assembly includes a cylindrical vessel for housing a superconducting magnet and having a vacuum between its inner and outer walls. The vessel defines a magnet bore for receiving a patient to be imaged. A gradient coil assembly is mounted in the bore adjacent the inner wall of the magnet assembly. To reduce gradient coil noise, the inner wall is constructed of a non-conductive material which does not support eddy currents.

Abstract: A sweep generator 230 applies a range of frequencies to an rf coil 140 to detect the resonant frequency of a field generated by a magnet 125a,b. A frequency to current converter 220 applies an auxiliary magnetic field to tune an MRI apparatus to the resonant frequency of the rf coil. A flexible coil of one turn (300) or two or more turns (500) has a plurality of segments (301-307; 501-513). One of the belt has a contact k0, (k0'), which is electrically connectable to one or more contacts k1, (k1'), k2, (k2'), etc. located between the ends of the segments. For each connection to successive contacts, the length of the coil and its inductance increases by the added impedance .DELTA.L.sub.ij between contacts k.sub.i and k.sub.j. That increase of inductance is nullified by capacitors .DELTA.C.sub.sij located between segments.

Abstract: An in-situ method for thermal desorption, extraction, and destruction of dense nonaqueous organic contaminants in fractured bedrock is accomplished through the use of thermal wells, a flameless oxidizer, and hot carbon adsorption chambers.

Abstract: A magnetic-resonance-imaging (MRI) scanner subassembly. In one subassembly, a preferably annularly-cylindrical-shaped enclosure contains a first vacuum, and an MRI gradient coil assembly is located within the enclosure in the first vacuum. Preferably, an annularly-cylindrical housing is included which is coaxially aligned with the enclosure and contains a second vacuum which is higher than the first vacuum, and an MRI superconductive main coil is located within the housing in the second vacuum. In another subassembly, an MRI gradient coil assembly has a threshold excitation frequency, and an isolation mount assemblage supports the MRI gradient coil assembly.

Abstract: An in-situ thermal desorption system which combines thermal desorption and vacuum extraction to separate organic compounds from in place contaminated soils is disclosed. A "heating blanket" desorption unit is applied directly to the surface of the hydrocarbon contaminated soil. The heating blanket assembly comprises of four basic components: a surface heating element, a thermal insulating mat, a vacuum collection system, and a vapor barrier. The surface heater, when energized, initiates a thermal front which moves down through the soil by thermal diffusion. As the soil is heated, organic compounds and water vapor are desorbed and removed from the soil matrix. A vapor collection system including a blower is fitted to the vapor barrier to establish a slight negative pressure inside the modular heating blanket units.