Siemens Aktiengesellschaft

Wilhelm Duerr

Ralph Oppelt

Horst Siebold

Markus Vester

Rainer Alfred Kuth

Norbert Krause

Andreas Potthast

Michael Moritz

Hartwig Ingwersen

Yutaka Watanabe

Gerhard Temmel

Norihiko Mikoshiba

Michael Knauth

Rainer Wirtz

Reiner Henkelmann

Rudolf Moder

A heat radiation shield has an electrically insulating support on which a mosaic of electrically conductive elementary layers is arranged on at least one side.

Heat radiation shield, and dewar employing same

A transmission/reception arrangement for a diagnostic magnetic resonance apparatus has an antenna, a matching and tuning circuit and a signal transmission line. The antenna together with the matching and tuning circuit is fashioned for exciting and/or receiving proton magnetic resonance signals having a first frequency. A reactance circuit is connected between the matching and tuning circuit and the signal transmission line. The reactance circuit is fashioned such that a reflection factor to the second transmission line substantially disappears at a second frequency. The apparatus is thus provided with the capability of conducting examinations using hyperpolarized gases, while still preserving the capability of conducting imaging with conventional proton (.sup.1 H) signals without modification.

Transmission/reception arrangement for a diagnostic magnetic resonance

In a mammography antenna arrangement for magnetic resonance examinations of a female breast, a conductor arrangement forms a closed circuit and surrounds a receptacle opening for the female breast. The receptacle opening lies in a surface that is essentially horizontally directed. Two arcuate conductor segments have their ends connected to the conductor arrangement via electrical connecting locations and surround an examination space that is fashioned for the acceptance of the female breast. The two conductor segments are respectively arranged in vertical, planes, the two planes being perpendicular to one another.

Mammography antenna arrangement for NMR examinations of a female breast

A head antenna for nuclear magnetic resonance examinations has an examination chamber, formed so as to accept the head, and an antenna conductor, formed as a frame antenna, that surrounds the examination chamber in an examination position. The antenna conductor is divided into two curved sub-conductors that respectively have electrical contacts at their ends for detachably electrically connecting the sub-contractors together. The first sub-conductor arrangement is fastened to a holding part which is arranged outside the examination chamber and which is made of an electrically non-conductive, non-ferromagnetic material. For fastening the holding part to a patient support, a first fastening assembly is arranged on the holding part. For fixing the position of the head, a second fastening assembly is arranged on the holding part.

Head antenna for nuclear magnetic resonance examinations

An antenna for a magnetic resonance apparatus has an antenna conductor that can be adapted to examination regions of different sizes, with one region of the antenna conductor divided into conductor sections. The conductor sections are connected to one another via capacitive elements, with the conductor sections and the capacitive elements connected alternating in series. The conductor sections are connectable to the remaining antenna conductor via releasable electrical connections.

Adaptable antenna for a magnetic resonance apparatus including a wiper

A mammography antenna arrangement for magnetic resonance examinations of the female breast has first and second conductor loop pairs, each of which is formed by two saddle-shaped conductor loops lying opposite one another and between which an essentially cylindrical examination space, having a receptacle opening, is located. The two conductor loop pairs are rotationally offset by 90.degree. relative to one another in the circumferential direction. A capacitive element is connected in a part of each conductor loop that faces away from the receptacle opening.

In a diagnostic magnetic resonance apparatus having an examination space, a radio-frequency antenna and a gradient coil system, the radio-frequency antenna is arranged closer to the examination space than is the gradient coil system. A radio-frequency shield arranged between the radio-frequency antenna and the gradient coil system, and has a first electrically conductive layer arrangement and a second electrically conductive layer arrangement arranged lying opposite the first arrangement, these being separated from one another by a dielectric. The layer arrangements have interconnects arranged side-by-side that are separated from one another by electrically insulating slots. The slots of the first layer arrangement are arranged offset relative to the slots in the second layer arrangement. Neighboring interconnects in at least one layer arrangement are connected to one another via bridges that conduct high-frequency currents, the bridges being arranged such that currents induced in the layer arrangement by the radio-frequency antenna can essentially flow only between the neighboring interconnects via the bridges.

Diagnostic magnetic resonance apparatus having a radio frequency shield

A radio-frequency antenna for a magnetic resonance apparatus has an antenna conductor in the form of a ribbon conductor. The ribbon antenna conductor has interconnects arranged side-by-side. Neighboring interconnects are connected to one another via bridges that conduct radio-frequency currents.

Radio-frequency antenna for a magnetic resonance apparatus

An antenna arrangement for a nuclear magnetic resonance apparatus, the apparatus having a magnet which generates a basic magnetic field between two pole plates, includes a sub-antenna disposed at each pole plate, each sub-antenna being composed of a closed, grounded shielding facing toward the pole plate and a planar conductor structure disposed a distance from the shielding and substantially parallel thereto, into which a high-frequency current is fed.

Antenna arrangement for a nuclear magnetic resonance apparatus

A high-frequency safety fuse has a fusible conductor having a cross-sectional area capable of carrying a high-frequency current, and two electrical terminals respectively connected to opposite ends of the fusible conductor. The cross-sectional area has a dimension in at least one direction which is approximately twice the penetration depth of the high-frequency current in the conductor. A fuse is thereby obtained having a low high-frequency equivalent resistance but also having a low cut-off current.

High-frequency safety fuse

In a magnetic resonance imaging tomography apparatus having a transmission antenna for exciting nuclear spins in an examination subject, and a reception antenna in the form of a local coil, the feeder for the local coil is provided with decoupling elements. The decoupling elements prevent a coupling of the electrical field of the transmission antenna with the feeder for the local coil.

Antenna system for a magnetic resonance imaging tomography apparatus

In a nuclear magnetic resonance tomography apparatus, having a high-frequency excitation and measuring coil connected with a capacitor to form a resonant circuit, the capacitor being tuned to a desired operating frequency, a circuit is provided for limiting the voltage of the resonant capacitor in a transmission mode. Avoidance of impermissible peak amplitudes is thereby achieved without the necessity of over-dimensioning the components of the resonant circuit.

Nuclear magnetic resonance tomography apparatus

A surface resonator for use in a magnetic resonance imaging apparatus having a transversal fundamental magnetic field is composed of two sub-systems, each generating a magnetic field with the magnetic fields being perpendicular relative to each other. Each sub-system contains two current loops, both of which enclose the magnetic field allocated to them in the same plane. A circularly polarizing surface resonator is thus obtained for the transversal fundamental magnetic field.

Surface resonator for a magnetic resonance imaging apparatus

A circularly polarizing RF antenna suitable for use in an MRI apparatus for obtaining tomograms of an examination subject includes two antenna systems, each having a winding, having two lateral legs and a middle leg, and a return path which form a resonant circuit in combination with one or more resonant capacitors. The middle legs of the two antenna systems are disposed so that they cross one another. One or more decoupling capacitors are provided between the two antenna systems. A circularly polarizing antenna for a magnetic resonance imaging system is thus obtained having a magnetic field vector in the imaging region which rotates in planes parallel to the pole surfaces of a C-shaped magnet which generates the fundamental magnetic field in the magnetic resonance imaging apparatus.

Circularly polarizing RF antenna for an MRI apparatus having a C-magnet

A resonator for use in a magnetic resonance imaging apparatus for transmitting and receiving high frequency signals is formed by a combination of two antenna sub-systems, which generate respective magnetic fields which are perpendicular to each other, with the currents in the sub-system being phase-shifted by 90.degree. relative to each other, and each sub-system includes a capacitance which defines the resonant frequency. Each of the sub-systems forms a current loop, the current loops containing a common current network and a common base plate, which serves as a return path for both current loops. The junctions of the current network are connected via the resonant capacitances to the base plate, which consists of electrically conductive material. A circularly polarizing resonator is achieved for the transversal, fundamental field of the imaging apparatus, with the resonator also being capable of use as a surface resonator if the spacing between the current network and the base plate is small.

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Erlangen, Germany

Wilhelm Duerr