Patents Assigned to CGR
  • Method for calibrating a radiofrequency excitation in NMR experimentation
    Patent number: 4788501
    Abstract: Size variation of samples subjected to NMR examinations entails the need for calibration of the radiofrequency excitation which gives rise to the resonance phenomenon measured during experiments. Determination of the most suitable value of the radio-frequency excitation amplitude is carried out by scanning the range of potential amplitudes, starting from one end of the range. During the scanning operation, the variation in excitation amplitude varies in a geometrical progression with the order number of the experimentation. It is shown that, by adopting this procedure, determination of the calibrated amplitude is achieved more rapidly while maintaining constant accuracy of determination.
    Type: Grant
    Filed: April 13, 1987
    Date of Patent: November 29, 1988
    Assignee: Thomson-CGR
    Inventors: Patrick LeRoux, Alain Marilier
  • Process for imaging by nuclear magnetic resonance
    Patent number: 4780674
    Abstract: The invention proposes an imaging process by nuclear magnetic resonance in which a calculated image is given corresponding to the molecular diffusion value at each point of an investigated medium. The diffusion image is obtained by comparing images relative to same sections of the medium and acquired during two excitation sequences, whereof one is not very sensitive to the diffusion and the other is particularly sensitive thereto. These two images undergo comparison in order to produce a diffusion image.
    Type: Grant
    Filed: December 24, 1986
    Date of Patent: October 25, 1988
    Assignee: Thomson-Cgr
    Inventors: Eric Breton, Denis Le Bihan
  • Radiogenic tube radiological device with magnetic bearings
    Patent number: 4780900
    Abstract: A radiological device is provided of the type comprising a radiogenic tube with magnetic bearings, said radiogenic tube being contained in a sheath as well as electronic means for controlling said magnetic bearings.
    Type: Grant
    Filed: April 23, 1986
    Date of Patent: October 25, 1988
    Assignee: Thomson-CGR
    Inventors: Emile Gabbay, Andre Plessis
  • Device for the cooling of an x-ray source
    Patent number: 4780901
    Abstract: A device is disclosed for the cooling of an X-ray tube contained in a casing, using a fluid put into forced circulation in a cooling circuit comprising a heat exchanger. The device of the invention can be used to obtain efficient cooling while, at the same time, using a small volume of fluid and a heat exchanger of smaller size than in the prior art. To this end, the cooling circuit comprises means to, firstly, store a quantity of heat accumulated by the fluid when the latter reaches a pre-determined temperature during an examination period and, secondly, to restore this quantity of heat during an idle period which follows the examination period.
    Type: Grant
    Filed: October 28, 1987
    Date of Patent: October 25, 1988
    Assignee: Thomson CGR
    Inventors: Emile Gabbay, Jacques Le Guen
  • Solenoidal magnet with high magnetic field homogeneity
    Patent number: 4774487
    Abstract: A structure is provided for connection between spaced Bitter coils in a magnet with homogeneous field. The magnet is formed of several Bitter coils spaced apart from each other and two adjacent coils are connected together by two groups of conductors symmetrical with respect to a plane and in which the current components create ampere turns in opposition.
    Type: Grant
    Filed: November 14, 1986
    Date of Patent: September 27, 1988
    Assignee: Thomson-CGR
    Inventor: Guy Aubert
  • Examination table with longitudinally movable top
    Patent number: 4773637
    Abstract: The invention pertains to an examination table, the top of which can be moved along its longitudinal axis on at least one roller. The top is moved, in relation to a pedestal, by a driving shaft which is set along one and the same crosswise axis as the roller.
    Type: Grant
    Filed: December 10, 1986
    Date of Patent: September 27, 1988
    Assignee: Thomson-CGR
    Inventor: Jean P. Jarin
  • Method for adjusting an x-ray device
    Patent number: 4774720
    Abstract: The method of adjustment of an x-ray device involves a step of entry of data relating to images to be produced and of data relating to the x-ray tube to be employed, a step of computation of x-ray tube parameters and a step of adjustment of the parameters in accordance with these computations. The number of images to be produced is included in the entry of image data and performs a major role in the optimization of computation of adjustment parameters with a view to ensuring that the image-recording time is as short as possible, thereby avoiding the problem of motional blur.
    Type: Grant
    Filed: July 30, 1986
    Date of Patent: September 27, 1988
    Assignee: Thomson-CGR
    Inventor: Claude Carbon
  • Method of identification of arborescent structures in digital images and its application to an image-processing device
    Patent number: 4771467
    Abstract: In a method for identification of arborescent structures detected in digital images by starting from model arborescent structures, a matching operation consists in comparing an object tree with a model tree. The method involves computation of the distance between the object tree and the model tree in accordance with a so-called Selkow iterative method which utilizes predefined cost values for elementary operations of label-changing, insertion or destruction of sub-trees in the descriptive lists of the trees to be identified. Starting from all the steps of computation of the distance measurement, the elementary operations which have served to arrive at the final distance are recorded and identification is obtained by label changes of the sub-trees reduced to branches.
    Type: Grant
    Filed: December 3, 1986
    Date of Patent: September 13, 1988
    Assignee: Thomson-CGR
    Inventors: Jean Y. Catros, Denis Mischler
  • Device to fasten and adjust a mandrel for holding gradient coils
    Patent number: 4755754
    Abstract: A mandrel for holding gradient coils in an instrument that measures nuclear magnetic resonance is fastened directly to the magnet of this instrument. It is shown that this arrangement can be used to reduce the output of noise while, at the same time, making it easy to adjust the position of the mandrel. The device comprises two sets of brackets fastened by their struts, on either side of the magnet, to the end rings of the magnet. Each bracket exerts a holding force on the mandrel.
    Type: Grant
    Filed: April 13, 1987
    Date of Patent: July 5, 1988
    Assignee: Thomson-CGR
    Inventors: Jacques Sireul, Claude Prevot, Bernard Rigeade
  • Radiological installation with adjustable transmission optical attenuator
    Patent number: 4749257
    Abstract: A radiological installation with dynamic compensation in the optical path of the image, with an optical attenuator with locally adjustable transmission placed at least in the vicinity of a focal plane in which the radiological image is formed situated upstream of the television camera of the image acquisition chain.
    Type: Grant
    Filed: April 16, 1986
    Date of Patent: June 7, 1988
    Assignee: Thomson CGR
    Inventor: Remy Klausz
  • Air-cooled high-frequency current transformer
    Patent number: 4748430
    Abstract: The transformer comprises a primary coil comprising a conductive strip wound around an insulating coil base comprising a central part, two parts located at the ends of the central part with a roughly rectangular shape, the bigger sides of which extend along a second and a third direction which are mutually opposite. The length of the central part, measured along the initial direction, is determined so that the two ends have the directions of their bigger sides colinear in pairs when the central part is wound around the coil base. The two angles, formed at the points where the edges of the parts located at the ends intersect the edges adjacent to the bigger sides of the central part, are truncated to prevent the overlapping of the two ends when the central part is wound around the coil base.
    Type: Grant
    Filed: November 17, 1986
    Date of Patent: May 31, 1988
    Assignee: Thomson-CGR
    Inventor: Noel Guais
  • Method for automatic determination of exposure of a radiographic film and an automatic film-exposing device for a diagnostic radiology installation in which said method is employed
    Patent number: 4748648
    Abstract: The exposure of a radiographic film to x-radiation transmitted through an intensifying screen during a period of exposure T is determined automatically in accordance with a method which achieves compensation for the effect of deviation from the reciprocity law by comparing a value representing the exposure attained by the screen-film pair with a reference value which is variable as a function of time in accordance with a predetermined law.
    Type: Grant
    Filed: July 1, 1986
    Date of Patent: May 31, 1988
    Assignee: Thomson-CGR
    Inventors: Jean Boucle, Jacques Delair
  • Solenoidal magnet with homogeneous magnetic field
    Patent number: 4748429
    Abstract: A resistive solenoid magnet with homogeneous field is provided more particularly for NMR image formation.According to the invention, the magnet comprises several coils preferably Bitter coils and some parameters such as the lengths of the coils, the distances which separate them and their outer diameter are chosen for optimizing the power-mass product of the magnet.
    Type: Grant
    Filed: August 13, 1986
    Date of Patent: May 31, 1988
    Assignee: Thomson-CGR
    Inventor: Guy Aubert
  • Solenoidal magnet with high magnetic field homogeneity
    Patent number: 4743879
    Abstract: A solenoidal magnet is provided with high magnetic field homogeneity, including a connection structure between spaced coils. The current between two adjacent spaced coils is transmitted in one direction by a longitudinal conductor and in the other direction by two longitudinal conductors disposed on each side of said first conductor.
    Type: Grant
    Filed: January 6, 1987
    Date of Patent: May 10, 1988
    Assignee: Thomson-CGR
    Inventor: Guy Aubert
  • Nuclear magnetic resonance imaging installation
    Patent number: 4742302
    Abstract: In order to generate a radiofrequency excitation signal in an installation for NMR imaging, the envelope of the radiofrequency pulse is deduced from the shape of the selected cross-section which would result from application of a radiofrequency pulse having an envelope representing the desired selected cross-section shape.
    Type: Grant
    Filed: September 11, 1985
    Date of Patent: May 3, 1988
    Assignee: Thomson-CGR
    Inventor: Eric Breton
  • Radiological installation having a single receiver
    Patent number: 4741014
    Abstract: A radiological installation for front and profile examinations using a single image receiver. The receiver is fixed to a transverse arm with respect to the table by means of a rotation shaft which may be locked in at least two predetermined positions, said arm forming part of a mobile support movable along said table.
    Type: Grant
    Filed: December 21, 1984
    Date of Patent: April 26, 1988
    Assignee: Thomson-CGR
    Inventor: Pierre C. Lajus
  • Gradient coil for image formation devices using nuclear magnetic resonance
    Patent number: 4740772
    Abstract: The object of the invention is an improved gradient coil. The improvement consists in making steps in the saddle-shaped conductors that form the coil in order to modify local distortions in the magnetic field produced. It is shown that the correction thus made has little effect on the rest of the field of distribution.
    Type: Grant
    Filed: October 15, 1986
    Date of Patent: April 26, 1988
    Assignee: Thomson-CGR
    Inventor: Claude Prevot
  • Orbit antenna for a nuclear magnetic resonance (NMR) imaging apparatus
    Patent number: 4739269
    Abstract: An orbit antenna for a nuclear magnetic resonance (NMR) imaging apparatus is symmetrized by joining together two concentric conductive loops in series. The antenna is frequency-tuned by a capacitor placed in parallel between the non-interconnected ends of the loops. A receiving circuit having a high input impedance is connected between the midpoint of the loops and one of the capacitor terminals. It is thus shown that the antenna is not unbalanced and endows the received signal with all the advantages of symmetrized antennas.
    Type: Grant
    Filed: January 5, 1987
    Date of Patent: April 19, 1988
    Assignee: Thomson-CGR
    Inventor: Jean P. Kopp
  • Method for the formatting and unformatting of data resulting from the encoding of digital information using a variable length code and a device for using this method
    Patent number: 4739308
    Abstract: The formatting/unformatting device of the invention especially comprises a formatting device made up of a justifier linked to an input register, the output of which is linked, through a multiplexer, to the residue input of the justifier as well as to a first intermediate register through another multiplexer and to another multiplexer. The latter multiplexer is linked to a second intermediate register and an output multiplexer, the output of which is linked to an output register which acts as a buffer for the bulk memory.
    Type: Grant
    Filed: January 12, 1987
    Date of Patent: April 19, 1988
    Assignee: Thomson-CGR
    Inventor: Jean Lienard
  • Method for calibrating the amplitude of radiofrequency excitation of a nuclear magnetic resonance imaging apparatus
    Patent number: 4739267
    Abstract: Calibration of radiofrequency excitation involves application of two successive pulses of identical waveform and amplitude. The excitations are applied in series of excitations of variable amplitude from one excitation to the next in order to determine the calibrated value of the excitation pulses to be employed by transition of the amplitude of the received signal through a minimum value. It is demonstrated that this procedure prevents the calibration from being impaired by inhomogeneities of the orienting field of the apparatus. Spatial and spectral inhomogeneities of the excitation are also eliminated by applying throughout the calibration a selection gradient to the body under examination. Defects are eliminated by frequency filtering of the detected signal.
    Type: Grant
    Filed: May 4, 1987
    Date of Patent: April 19, 1988
    Assignee: Thomson-CGR
    Inventors: Patrick Leroux, Alain Marilier