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4739481 X-ray CT image processing apparatus
XIII
New Patents
value of the ,difference between the Larmor frequencies of water-bound hydrogen protons on the one hand and fat-bound hydrogen protons on the other hand, or to an odd multiple thereof.
4739267 METHOD FOR CALIBRATING TH[E AMPLITUDE OF RADIOFREQUENCY EXCITATION OF A NUCLEAR MAGNETIC RESONANCE IMAGING APPARATUS Patrick Leroux, Alain Marilier, Paris, France assigned to Thomson-CGR 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 excitatio-n 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.
4739269 ORBIT ANTENNA FOR A NUCLEAR MAGNETIC RESONANCE (NMR) IMAGING APPARATUS Jean Kopp, Montigny le Bretonneux, France assigned to Thomson-CGR An orbit antenna for a nuclear magnetic is imaging apparatus resonance (NMR) 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.
4739271 DECOUPLING MULTIPLE-COIL NMR PROBES Axe1 Haase, Goettingen, Federal Republic Of Germany assigned to Max-Planck-Gesellschaft A circuit arrangement is described for preventing a reaction of a coil on an external highfrequency field of predetermined frequency containing the coil due to a current induced by the field in the coil for a multiple-coil probe of a nuclear magnetic resonance apparatus wherein the coil,is coupled via a high-frequency line of predetermined characteristic impedance to a switching element and a circuit unit cooperating with the coil. The electrical length of the highfrequency line between the coil and the switching element is so dimensioned that any undesired reaction of an inactive coil on the other coil(s) is eliminated.
4739481 X-RAY CT IMAGE PROCESSING APPARATUS Eiji Yoshitome, Tokyo, Japan assigned Yokogawa Medical Systems Limited
to
This invention concerns an X-ray CT image processing apparatus capable correcting the boneinduced beam hardening only based on the reconstructed image data at a high speed and simply, in which the bone region of the reconstructed image is discriminated based on the reconstructed image data, a correcting image data is determined through the masked addition or convolution of a 2-dimensional weight function using thus discriminated bone region as a mask and the correcting image data are added to the reconstructed image data.
4739521 MEDICAL
IMAGE DIAGNOSTIC SYSTEM
Taiz Akimoto, Kanagawa, Fuji Photo Film Co Ltd
Japan assigned to
New Patents
value of the ,difference between the Larmor frequencies of water-bound hydrogen protons on the one hand and fat-bound hydrogen protons on the other hand, or to an odd multiple thereof.
4739267 METHOD FOR CALIBRATING TH[E AMPLITUDE OF RADIOFREQUENCY EXCITATION OF A NUCLEAR MAGNETIC RESONANCE IMAGING APPARATUS Patrick Leroux, Alain Marilier, Paris, France assigned to Thomson-CGR 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 excitatio-n 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.
4739269 ORBIT ANTENNA FOR A NUCLEAR MAGNETIC RESONANCE (NMR) IMAGING APPARATUS Jean Kopp, Montigny le Bretonneux, France assigned to Thomson-CGR An orbit antenna for a nuclear magnetic is imaging apparatus resonance (NMR) 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.
4739271 DECOUPLING MULTIPLE-COIL NMR PROBES Axe1 Haase, Goettingen, Federal Republic Of Germany assigned to Max-Planck-Gesellschaft A circuit arrangement is described for preventing a reaction of a coil on an external highfrequency field of predetermined frequency containing the coil due to a current induced by the field in the coil for a multiple-coil probe of a nuclear magnetic resonance apparatus wherein the coil,is coupled via a high-frequency line of predetermined characteristic impedance to a switching element and a circuit unit cooperating with the coil. The electrical length of the highfrequency line between the coil and the switching element is so dimensioned that any undesired reaction of an inactive coil on the other coil(s) is eliminated.
4739481 X-RAY CT IMAGE PROCESSING APPARATUS Eiji Yoshitome, Tokyo, Japan assigned Yokogawa Medical Systems Limited
to
This invention concerns an X-ray CT image processing apparatus capable correcting the boneinduced beam hardening only based on the reconstructed image data at a high speed and simply, in which the bone region of the reconstructed image is discriminated based on the reconstructed image data, a correcting image data is determined through the masked addition or convolution of a 2-dimensional weight function using thus discriminated bone region as a mask and the correcting image data are added to the reconstructed image data.
4739521 MEDICAL
IMAGE DIAGNOSTIC SYSTEM
Taiz Akimoto, Kanagawa, Fuji Photo Film Co Ltd
Japan assigned to