Picker International, Inc.

Koninklijke Philips Corporation N.v.

Gec-marconi Limited

Other

Ericsson Ab

David John Gilderdale

David James Larkman

Anthony J Salloway

Anthony Charles Grantham

John Brian Pendry

Ian R Young

Joseph Vilmos Hajnal

Michael Charles Keogh Wiltshire

Nandita M deSouza

Glyn A Coutts

A material having magnetic permeability at r.f. frequency, for example a microstructured magnetic material has a magnetic permeability of negative value but unity magnitude over a particular r.f. frequency range. The singularity in the flux pattern has the result that magnetic resonant disturbances in a plane C,E normal to the line C,D are focussed into a plane D,F also normal to the line C,D and vice versa. This is particularly applicable to magnetic resonance apparatus, since the material can be used to transfer the r.f. magnetic flux distribution in a target region in a patient, for example at C,E to D,F where the flux may be directly measured by receive coils. Equally, transmit coils may generate flux to be focussed into the target region by the material. Magnetic resonance apparatus may be constructed which does not require gradient coils, and r.f. hypothermia may be carried out in a focussed way, minimising damage to surrounding tissue.

Material having magnetic permeability at R.F. frequency

An MRI apparatus includes a local endovaginal probe ( ) for receiving magnetic resonance in a study of the endopelvic fascia surrounding the female urethra. The probe ( ) includes a shaft portion ( ) an insert portion ( ), the insert portion to be inserted into the vaginal cavity of a female subject. The insert portion ( ), in order to have maximum efficiency in imaging the endopelvic fascia, is designed to specific dimensions to achieve the optimum balance between image quality and patient comfort. In an imaging sequence, a main magnet assembly ( ) produces a main magnetic field through an imaging region ( ). A whole-body RF coil ( ) excites and manipulates magnetic resonance in the vicinity of the vaginal cavity. The probe ( ) detects the magnetic resonance, which is received and demodulated. The received magnetic resonance is then reconstructed into an image representation of the tissue surrounding the vaginal cavity of the subject.

Endovaginal MRI receiver coil

In an endoscope, the tip which contains passages for viewing and light guiding is made of plastics material, for MR compatibility purposes, and an r.f. receive coil of the endoscope is provided with a fiducial having its own r.f. receive coil, to make it possible to track movement of the r.f. receive coil.

Endoscope suitable for magnetic resonance imaging

A magnetic resonance imaging probe includes a dipole including a first arm and a second arm. The second arm includes an elongate loop coil. In one embodiment, the loop coil is an open coil. In another embodiment, the coil is a twisted coil. The first and second arms are electrically connected to provide a dipole output. The second arm is electrically connected to a loop output.

Probe for magnetic resonance imaging

An RF coil structure for intra-cavity use includes a pair of conductors (,) separated by a support such as a web (,) which come together at positions separated along the length of the coil structure such as (A, B). Previous coils have included two parallel conductors. If the conductors (,) and (,) were parallel, while the structure could be flexed transverse to the plane of the web (,) about the arrow (,), it could not be flexed in the plane of the web (,) about arrows (,). Because the conductors come together at points (A) and (B), it can be so flexed. A second coil may be provided including conductors (,) and flexing about the same points as for the first coil is still possible because the points of closest approach for one pair come between those for the other pair.

RF coil structure for intra-cavity use in magnetic resonance imaging

A method and coil arrangement for use in magnetic resonance imaging facilitates the examination of a localized region of the body. A plurality of substantially identical saddle coils are disposed about a former. The coils, which define a generally cylindrical volume, overlap one another in a circumferential direction. In one embodiment, a generally planar rectangular coil intersects the cylindrical volume. The method and coil arrangement are particularly well suited to imaging a region adjacent but outside the cylindrical volume. The coil arrangement is also well suited to insertion within the body, especially the rectum.

Magnetic resonance methods and apparatus

An MR compatible endoscope 1 has associated MR saddle coil 10 mounted on a removeable former 9. The tip 2 of the endoscope has the usual service channels for imaging. The coil 10 provides an additional MR signal. To avoid the need to plug the coil 10 in, it is inductively couples to a pick-up coil 13 and, to enable this to be removable as will from the endoscope, this may be located in one of the service channels 7 of the endoscope. The removable nature of the coil permits easy repair and, more importantly, a range of coils to be fitted to the endoscope to accommodate different magnetic field strengths.

Nuclear magnetic resonance imaging apparatus

In a magnetic resonance apparatus including a transducer (25, 31 ) positioned in the examination region of the apparatus, the transducer is connected with equipment (49) outside the examination region by way of a lead (47) which is grounded (51, 53) to signals of the frequency of the RF field applied to a subject (5) in the examination region to excite magnetic resonance in the subject, at a distance along the lead from the transducer equal to a quarter wavelength at the RF field frequency (or an odd multiple thereof). Distortion of the RF field due to loading by the transducer is thereby reduced. The transducer may, for example, be a microphone or loudspeaker, e.g. incorporated in an intercom or active noise reduction arrangement, or a sensor for sensing a condition of a patient being examined.

Reduction of RF field disturbance in magnetic resonance apparatus

In a magnetic resonance apparatus including an active noise reduction arrangement (9, 49, 51, 53) for use by a patient (5) undergoing examination in the apparatus the transducers (25, 31) of the arrangement are non-magnetic, e.g. are of the electret, piezoelectric or condenser type, and have no parts of ferromagnetic material.

Magnetic resonance apparatus

A magnetic resonance apparatus including an r.f. coil arrangement (13) for detecting and/or exciting magnetic resonance in a body in use of the apparatus, the coil arrangement comprising a cylindrical coil (25) and two saddle coils (29) which are disposed in register on opposite sides of the cylindrical coil and conform to the surface of the cylindrical coil. In use of the apparatus the coil arrangement is disposed with the axes of the coils lying in a plane orthogonal to the direction of a static field applied to the body.

In a nuclear magnetic resonance apparatus and RF coil arrangement comprises two or more separable parts (51 and 53) adapted to be assembled around the body to be examined to form the coil arrangement. The parts are suitably arranged to be connected, when assembled, by adjustable coupling structure (55, 57, 59 and 61) so that the volume embraced by the coil arrangement may be adjusted. The invention enables the coil arrangement to be positioned more closely around a body being examined than is possible with conventional, unitary, tubular coil arrangements.

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South Devon, United Kingdom

David John Gilderdale