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4565968 Blood vessel projection imaging system using nuclear magnetic resonance
New Patents
III
4564812
4565968
NUCLEAR MAGNETIC RESONANCE TOMOGRAPHY APPARATUS INCLUDING A FARADAY CAGE
BLOOD VESSEL PROJECTION IMAGING SYSTEM USING NUCLEAR MAGNETIC RESONANCE
Pieter Van Dijk, Eindhoven, Netherlands signed to U S Philips Corporation
as-
A nuclear magnetic resonance tomography apparatus includes a Faraday cage which shields the measurement space against stray electromagnetic fields, and increases the Q factor of comprising the transa coil circuit mitting/receiving coils of the apparatus. This Faraday cage is arranged around the object space inside the magnetic coils for generating the necessary steady magnetic field, but around and outside the RF transmitting/receiving coil. The transmitting/receiving coil may be provided with comb-like screens which shield against electrical fields, and the Faraday cage may include a readily accessible extension having larger transverse dimensions.
Albert Macovski A two-dimensional projection image of the NMR activity within a volume is obtained. The signals due to static material are cancelled and do not appear in the projection image. The signals due to moving blood in vessels produce an isolated image of the vessels with the superimposed structure removed. The excitation of a plane is accomplished using a single excitation pulse without requiring an a.c. gradient. The uniformity requirement of the inversion excitation is minimized. Images are generated which distinguish the direction of flow.
4567440 VIVO P-31 NMR IMAGING OF PHOSPHORUS METABOLITES 4564813 NUCLEAR MAGNETIC RESONANCE METHOD AND APPARATUS Ian R Young, David R Bailes, Sunbury on Thames, United Kingdom assigned to Picker International Ltd A method of nuclear magnetic resonance imaging of a body in which the spins of a chosen nucleus in a selected slice of the body are rotated through an angle appreciably greater than 90 degrees. Two r.f. pulses, each accompanied by a magnetic field having a gradient in a direction parallel to the equilibrium axis of magnetic alignment of the spins are applied in sequence. Each e.f. pulse is at the Larmor frequency for the nuclei in the slice in the presence of the associated field gradient and each r.f. pulse is effective to rotate the spins by not greater than 90 degrees. The r.f. pulses together are sufficient to rotate the spins through the desired angle, the gradients of the magnetic fields being in opposite directions.
John Haselgrove A system for imaging P-3 1 spectra from different slices through a living body specimen positioned in the bore of the hollow main field magnet of an NMR spectrometer, consisting of applying a timed series of different discrete differentamplitude magnetic field gradient pulses to the specimen, whereby to generate time-spaced echo signals from respective points along the specimen while timed RF resonance excitation pulses are applied to the specimen. The echo signals are used to derive respective chemical shift spectra from the points, each spectrum containing information showing the in vivo metabolic state at one of the points. The various spectra can be simultaneously displayed to enable concurrent slice-by-slice interpretation of the metabolic information. The gradient pulses are derived from coils mounted inside the main field magnet arranged to generate a magnetic field vector traversing the specimen. The gradient coils are energized by using a suitably programmed computer. The gradient current pulses are applied concurrently with the RF excitation pulses.
III
4564812
4565968
NUCLEAR MAGNETIC RESONANCE TOMOGRAPHY APPARATUS INCLUDING A FARADAY CAGE
BLOOD VESSEL PROJECTION IMAGING SYSTEM USING NUCLEAR MAGNETIC RESONANCE
Pieter Van Dijk, Eindhoven, Netherlands signed to U S Philips Corporation
as-
A nuclear magnetic resonance tomography apparatus includes a Faraday cage which shields the measurement space against stray electromagnetic fields, and increases the Q factor of comprising the transa coil circuit mitting/receiving coils of the apparatus. This Faraday cage is arranged around the object space inside the magnetic coils for generating the necessary steady magnetic field, but around and outside the RF transmitting/receiving coil. The transmitting/receiving coil may be provided with comb-like screens which shield against electrical fields, and the Faraday cage may include a readily accessible extension having larger transverse dimensions.
Albert Macovski A two-dimensional projection image of the NMR activity within a volume is obtained. The signals due to static material are cancelled and do not appear in the projection image. The signals due to moving blood in vessels produce an isolated image of the vessels with the superimposed structure removed. The excitation of a plane is accomplished using a single excitation pulse without requiring an a.c. gradient. The uniformity requirement of the inversion excitation is minimized. Images are generated which distinguish the direction of flow.
4567440 VIVO P-31 NMR IMAGING OF PHOSPHORUS METABOLITES 4564813 NUCLEAR MAGNETIC RESONANCE METHOD AND APPARATUS Ian R Young, David R Bailes, Sunbury on Thames, United Kingdom assigned to Picker International Ltd A method of nuclear magnetic resonance imaging of a body in which the spins of a chosen nucleus in a selected slice of the body are rotated through an angle appreciably greater than 90 degrees. Two r.f. pulses, each accompanied by a magnetic field having a gradient in a direction parallel to the equilibrium axis of magnetic alignment of the spins are applied in sequence. Each e.f. pulse is at the Larmor frequency for the nuclei in the slice in the presence of the associated field gradient and each r.f. pulse is effective to rotate the spins by not greater than 90 degrees. The r.f. pulses together are sufficient to rotate the spins through the desired angle, the gradients of the magnetic fields being in opposite directions.
John Haselgrove A system for imaging P-3 1 spectra from different slices through a living body specimen positioned in the bore of the hollow main field magnet of an NMR spectrometer, consisting of applying a timed series of different discrete differentamplitude magnetic field gradient pulses to the specimen, whereby to generate time-spaced echo signals from respective points along the specimen while timed RF resonance excitation pulses are applied to the specimen. The echo signals are used to derive respective chemical shift spectra from the points, each spectrum containing information showing the in vivo metabolic state at one of the points. The various spectra can be simultaneously displayed to enable concurrent slice-by-slice interpretation of the metabolic information. The gradient pulses are derived from coils mounted inside the main field magnet arranged to generate a magnetic field vector traversing the specimen. The gradient coils are energized by using a suitably programmed computer. The gradient current pulses are applied concurrently with the RF excitation pulses.