摘要:
Disclosed herein are embodiments of segmented metallic guidewires that are suitable for MRI catheterization. Disclosed guidewires comprise a plurality of short conductive metallic segments that individually are short enough such that they do not resonate during MRI. The conductive segments are electrically insulated from each other and mechanically coupled together end-to-end via connectors, such as stiffness matched connectors, to provide a sufficiently long, strong, and flexible guidewire for catheterization that is non-resonant during MRI.
摘要:
Featured are a device with localized sensitivity to magnetic resonance signals, an imaging system using such a device and MRI methods for performing internal MRI or MRI Endoscopy. Such an MRI method includes introducing an MRI antenna or probe into the specimen to be imaged, the antenna being configured in accordance with the devices described herein, so that the spatial coordinate frame of imaging is inherently locked or defined with respect to the introduced antenna thereby providing imaging of the specimen from the point of view of the antenna. Further such imaging is conducted so that the MRI signal is confined substantially to a volume with respect to a particular region of the antenna or probe.
摘要:
An apparatus for use in a magnetic resonance system including an operative component configured to perform a useful operation in a magnetic resonance system; an electrical cable connected with the operative component to provide electrical communication with the operative component; and a resonant circuit including at least a portion of the electrical cable, the resonant circuit having a first impedance pole at a first magnetic resonance frequency and a second impedance pole at a second magnetic resonance frequency different from the first magnetic resonance frequency.
摘要:
A transmission cable for use in a magnetic resonance apparatus is provided. The transmission cable includes a plurality of cable segments (200n). The cable also includes a plurality of couplers each of which transforms a first signal carried by a first cable segment into an acoustic signal and from the acoustic signal into a second signal carried by a second cable segment.
摘要:
The use of standard coaxial cables for, e.g. connecting optional receive MR coils to MR-scanners has the problem that parasitic cable resonances may occur, which may cause RF burns to a patient. According to the present invention, the cable is divided into a huge number of small pieces. Each conductor in the small pieces is connected to the respective conductor in another small piece via a series capacitor. Due to this, e.g. at MR frequency, the cable according to the present invention is completely off resonant, such that no parasitic resonance may occur.
摘要:
La présente invention concerne une antenne volumique radiofréquence (100), comportant une pluralité de conducteurs longitudinaux (2) et un circuit de désaccord pour modifier la fréquence de résonance du mode propre de ladite antenne (100) apte à désaccorder ladite antenne sans contact avec lesdits conducteurs longitudinaux (2), ledit circuit de désaccord étant composé par une pluralité de circuits résonants (8) présentant un dispositif de commutation (11) et résonant : à une première fréquence de résonance proche de la fréquence de résonance du mode propre de ladite antenne lorsque le moyen de commutation (11) est en position fermée de manière à induire par effet inductif une réactance sur chaque conducteur longitudinal (2) et à modifier la fréquence de résonance du mode propre de ladite antenne (100) ; à une deuxième fréquence de résonance supérieure ou inférieure à la fréquence de résonance du mode propre de ladite antenne de manière à minimiser le couplage entre le circuit de désaccord et les conducteurs longitudinaux (2) lorsque ledit moyen de commutation (11) est en position ouverte, ladite antenne volumique étant caractérisée en ce que l'antenne est une antenne quart-d'onde et en ce que les circuits résonants (8) sont positionnés longitudinalement dans l'antenne (100) à une position où le champ magnétique B1 est maximal.