Abstract: An rf surface coil for MRI is described. The surface coil is made of a trace of a high conductivity material having a length, width and thickness and having a surface defined by the length and the width. The coil has a radius and a longitudinal axis at the center of the coil. The trace is arranged in a loop with one end in proximity to the other end with the surface facing the inside of the loop, wherein the surface is substantially parallel to the longitudinal axis of the coil. The ratio of the width of the coil to the radius of the coil is 0.3 or greater and the thickness of the trace is sufficient to provide an rf skin effect. Circuit designs for inductively coupling the decoupling the surface coil from a volume coil during rf excitation are also described.

Abstract: A cavity resonator is disclosed for use in nuclear magnetic resonance (NMR) systems. The resonator has a housing defining a cavity having a selected length and cross-sectional shape. A layer of electrically conductive material is provided around at least a portion of the housing enclosing a dielectric material (air, gasses, teflon, etc.) and the cavity is energized at a Larmor radio frequency useful for NMR systems. The cavity, i.e. a volume enclosed by conductive walls, furthermore, is dimensioned to resonate at the selected radio frequency to thereby generate an alternating magnetic field through the cavity. An opening in the housing is adapted to be placed adjacent an object to be analyzed.

Abstract: A method of and apparatus for centrally monitoring the capacity of batteries in a battery string includes electrical leads connected to each battery terminal of the battery string. A capacity testing system a) switches between the electrical leads for sequentially selecting the leads associated with the terminals of each battery, b) measures the internal resistance of the battery associated with each selected pair of electrical leads, c) compares the internal resistance of each battery cell to an internal resistance threshold, and d) triggers an alarm when the internal resistance of a battery exceeds the internal resistance threshold.

Abstract: In a magnetic resonance imaging (MRI) system, a method is provided for reducing oblique Nyquist ghost artifact in an image produced by an oblique EPI scan. Prior to commencing the EPI scan, referencing pre-scans are conducted to generate pre-scan echo trains respectively corresponding to the physical gradient axes. Distortion compensating parameters are derived from the pre-scan echo trains for reducing Nyquist ghost by alternatively modifying the data acquisitions stage of the oblique EPI scan, or the post-data acquisition image processing stage thereof. In one mode of operation, the pre-scan echo trains are generated while a subject is in the MRI system. In another mode of operation, pre-scan echo trains are generated while no subject is present in the MR system, so that the distortion compensating parameters represent characteristics of the MR system only, and thus may be used for EPI scans of different protocols.

Abstract: A magnetic resonance imaging apparatus includes a main magnet having a frame (19) with two magnetic elements (1) arranged thereon. The magnetic elements (1) have substantially parallel faces (3) that face each other so as to define a gap (5) between the magnetic elements. The magnetic elements (1) have magnetic poles of opposite polarities for generating a static magnetic field in the gap (5). A patient support (45) is provided for supporting a patient (47) so that a part of the patient that is to be examined is located in the gap (5). In order to improve the accessibility of the patient (47) without increasing the width of the gap (5), a supporting member (37) is arranged so as to support the frame (19) in such a position that the normals (41) to the planes of the substantially parallel faces (3) of the magnetic elements (1) extend in a direction that encloses an angle between 30.degree. and 60.degree. with the vertical direction.

Abstract: A method and apparatus for structural elucidation and determination of a nanoliter size sample of analyte. The method includes separating the analyte using a microseparation technique and then substantially simultaneously analyzing or detecting the sample using a nuclear magnetic resonance (NMR) spectrometer. The apparatus includes an RF microcoil positioned for operable communication with a capillary member of the microseparation system and the NMR spectrometer to provide enhanced sensitivity and improved signal-to-noise ratio of the NMR spectrometer necessary to accurately analyze or detect nanoliter size samples.

Abstract: A method for treating M-degree oversampled impulse response data in real time includes generating N initial pseudo-data points derived from an N tap digital filter, processing each datum therewith, down sampling by a factor of r and displacing the processed datum toward the time origin by an appropriate amount. After fourier transform of the data set, the spectral background information bears improved fidelity to the actual spectral noise.

Abstract: A real-time, on-line nuclear magnetic resonance (NMR) system, and related method, can predict various properties of interest of a sample of polymer material. A regression or neural network technique is used to develop a model based upon manipulated NMR output and a resin age factor which compensates for time dependent aging phenomena and enhance predictive accuracy of the model. In a preferred embodiment, the resin age factor is a function of elapsed cycle time prior to sample measurement, sample temperature at time of measurement, and/or sample form. The polymer can be a plastic such as polyethylene, polypropylene, or polystyrene, or a rubber such as ethylene propylene rubber.

Abstract: A system produces high-resolution magnetic resonance (MR) images from the data measured by the magnetic resonance machine. The system extrapolates, using a method "ad hoc", a function of the measured data. This makes it possible to reduce the number of data measured, giving consequent reduction in the overall measurement time. Further, a special contrast measurement is used, which makes it possible to choose the image automatically from a group of possible candidates, consistent with the measured data.

Abstract: An MRI apparatus and method useful for both industrial applications and medical applications is provided. The apparatus and procedures are capable of estimating the value of a continuous property, such as concentration, viscosity or the like by interpolating or extrapolating from a model derived from training sets of data representing measurements of samples with known properties. A number of techniques are provided for objectifying the analysis. Cluster analysis techniques can be used to supplement, assist or replace subjective judgments by trained operators. Calculations or judgments regarding similarity can be made with respect to stored libraries of signatures, particularly where the library of stored signatures is obtained objectively, e.g., using cluster analysis, standardization and calibration. The signatures can be expanded signatures which include non-MR as well as MR data.

Abstract: The present invention provides an antenna assembly capable of operating in high temperature and pressure environments without delaminating. In this antenna assembly, the ferrites are separately impregnated with an epoxy resin under pressure and temperature and maintained at said temperature and pressure until each is cured. A low viscousity resin having a low glass transition temperature can be used to assure that the ferrites were completely impregnated with resin. The impregnated resin ferrites are then assembled into an antenna assembly and wrapped with fiberglass reinforcement. Thereafter, the entire antenna assembly is then potted under temperature and pressure to eliminate voids or air spaces, between assembly components, in order to assure a void free assembly. The fiberglass acts as a band to hold the antenna assembly together. Since the fiber has a low coefficient of expansion in the direction of the wrap, the assembly is held tightly together and is more reliable during well-logging procedures.

Abstract: A MR method determines nuclear magnetic resonance distribution in an examination area and the position of at least one microcoil which is located in the examination area in or on an examination object. In the presence of a homogeneous stationary magnetic field acting on the examination area, sequences are carried out in which at least one high-frequency pulse acting on the examination area is generated, and after the high-frequency pulse an MR signal induced in the microcoil is detected under the influence of a gradient magnetic field that acts on the examination area. Then the position of the microcoil in the gradient direction defined by the gradient field is derived from the detected MR signal. The aforementioned sequences are repeated for another gradient direction, and MR signals are detected by a further receiving coil arrangement to determine the nuclear distribution.

Abstract: A method for correcting MR data elements acquired in the presence of an imperfectly linear gradient field, each element comprising nominal first and second quadrature components. The quadrature components are multiplied by an artifact correction factor to provide respective first and second quantities. A Gradwarp geometric correction operation is applied to respective quantities to provide a corrected first and second quadrature component, corresponding to each data element. For a given data element, the arctangent function is applied to the result obtained by dividing the first corrected component by the second corrected component to provide a corrected phase component for use in forming an image.

Abstract: A multiconductor continuity and intermittent fault analysis system that sects the cable to controlled environmental stress stimuli, such a vibration at controlled frequencies, during testing. Multiconductor cables used for the transmission of digital data and control signals include multiple individual conductors terminating at both ends in pins or sockets that are grouped together in a connector. Physical defects in these cables can be permanent, or they can be intermittent faults, such as temporary breaks or shorts caused by vibrational stress on the cables. By vibrating the cable under test and measuring continuity rapidly enough to detect short-term anomalies, even intermittent faults are located.

Abstract: A method for operating a superconductive magnet having a superconductor. The magnet is ramped to generally the design current. After that, the magnet is brought to an annealing temperature which is above the operating temperature and below the critical temperature. After that, the magnet is shimmed at a shimming temperature which is at least as cold as the annealing temperature. After that, the magnet is used, at the operating temperature, for a predetermined purpose, such as MRI imaging for medical diagnosis. Preferably, the superconductor has less than twenty-five superconductive filaments.

Abstract: A subject receiving bore (12) of a magnetic resonance apparatus has an axial length to diameter ratio of less than 1.75:1 and preferably about 1:1. The temporally constant magnetic field generated by superconducting magnets (10) surrounding the bore has various magnetic field harmonic distortions including a Z12 harmonic distortion which is described generally by the equation Z.sup.12. In long bore magnets with a length to diameter ratio of 2:1 or more, harmonic distortions above Z6 are not present, or if present, not measured. A magnetic field probe (80 ) measures the magnetic field in the bore at a sufficient number of axial locations to measure at least the Z12 harmonic, e.g., 24 axially displaced locations. The probes are sampled at a sufficient number of angular increments, e.g., 32-36, that any present transverse spherical harmonics are sampled. Ferrous shims (62) are mounted in the bore in the pockets (58) of shim trays (44) to compensate for the Z12 and other sampled harmonics above Z6.

Abstract: A magnetic resonance (MR) method utilizes a plurality of inductively coupled receiving coil systems quasisimultaneously to measure a nuclear magnetization distribution in an examination zone. The method involves excitation of the nuclear magnetization in an examination zone, exposed to a uniform, steady magnetic field, by means of at least one RF pulse, multiple rephasing of the exited nuclear magnetization in order to generate a plurality of MR echo signals whose number at least equals the number m of receiving coil systems, and switching over the receiving coil systems in such a manner that, subsequent to said excitation, each receiving coil system receives at least one MR echo signal while at the same time alii respective other coil systems are inactive.

Abstract: A circuit arrangement for indicating the charge status of a batter in an electrical appliance includes a voltage comparator with hysteresis which detects the battery voltage, an oscillator driven by the voltage comparator, and an indicating device. The oscillator oscillates when the voltage is above a first threshold voltage and switches the indicating device to an active condition. The oscillator is blocked when the voltage is below a second threshold voltage and switches the indicated device to a passive condition.

Abstract: For measuring the basic field, at least one magnetic field probe is attached in the examination region of the nuclear magnetic resonance tomography system. The influence of the magnetic field gradients on the measurement is eliminated by a correction stage for pulsed magnetic field gradients arising from the switched gradients.

Abstract: A permanent magnet of a pulsed nuclear magnetic resonance (NMR) device is positioned within a drill collar for evaluating earth formations. In this way, the torsional and bending strengths of the drill collar are maximized with relatively little sacrifice of the magnetic moment of the permanent magnet. The resulting tool makes NMR measurements while the formation is being drilled. An antenna for producing and detecting an oscillating RF field in the earth formation is either located in a groove in the outer surface of the drill collar, or in an alternative embodiment, the drill collar itself serves as an RF antenna.