The University of Queensland

Nmr Holdings No. 2 Pty Limited

Magnetica Limited

University of Tasmania

Stuart Crozier

David Michael Doddrell

Feng Liu

Bing Keong Li

Huawei Zhao

Ewald Weber

Kurt Luescher

Wolfgang Udo Roffman

Lawrence Kennedy Forbes

Stephen James Wilson

Ben Lawrence

Adnan Trakic

Desmond Yau

Riyu Wei

Michael Thomas Gladwin

Wolfgang Udo Roffmann

Ian Gregg

Hua Wang

Wang Hua

A magnetic resonance imaging (MRI) system uses a superconducting magnet having a primary coil structure and a shielding coil layer. The primary coil structure comprises at least three sets of coils with significantly different inner diameters, forming a three-bore magnet structure. The three bores are coaxially aligned with a longitudinal axis, with the largest diameter first bore on one side of the magnet and the smallest diameter third bore on another side of the magnet, as well as a medium diameter second bore located axially between the first and the third bores. The first bore allows access for the head and shoulders and permits the head to enter into the second bore for imaging, while the patient's extremities (hands, legs) may access through the third bore for producing images of the extremity joints. The magnet may also be used for other specialist imaging where use of a whole-body MRI is unwarranted, such as the imaging of neonates. Reinforcing plates can be connected between coil formers to withstand the forces generated by the high magnetic fields.

Magnet for head extremity imaging

A coil arrangement for use in a magnetic resonance imaging system, the imaging system being for generating a magnetic imaging field in an imaging region, the coil arrangement including at least three coils for at least one of transmitting, receiving or transceiving an electromagnetic field, each coil being provided on a coil geometry and being substantially orthogonal.

Coil arrangement for use in a magnetic resonance imaging system

A coil for a magnetic resonance imaging device consists of multiple coil elements arranged about an imaging space. Each coil element comprise radiating structures oriented at an angle to a tangent of the imaging space. Angling the radiating structures reduces mutual coupling between coil elements and enhances the penetration of the radio frequency field to the imaging space.

MRI coil design with volumetric trough-shaped coil elements

Apparatus for use in a magnetic resonance imaging system, the imaging system generating a magnetic imaging field in an imaging region (), the apparatus including at least one coil for at least one of transmitting, receiving or transceiving an electromagnetic field, a field component () (such as a coil or a shield) and a drive () coupled to the field component for moving the field component () relative to the imaging region () to thereby modify the electromagnetic field during imaging process. The same concept can also be applied to nuclear imaging or nuclear spectroscopy apparatus.

MRI apparatus and method with moving field component

A magnetic resonance system uses a shielded superconducting magnet to produce a dsv useful for specialist imaging in an overall short magnet system at field strengths 1.5 Tesla and above. The magnet includes at least a first central coil C, which has a length of at least 25% of the overall length of the magnet, and is used in concert with a series of symmetric primary coils, at least one set of which carry current in a direction opposite to that of the central coil. Force balancing is advantageously used in the design of the coils. The primary coils are shielded by at least one shielding coil, which carries current in a direction opposite to the majority of the primary coils. The magnet resonance system can be used for orthopedic imaging.

Magnets for use in magnetic resonance imaging

A Magnetic Resonance Imaging (MRI) phased array head coil () comprises an array of coils () a decoupling circuit () and a decoupling base (). Counter wound inductors from adjoining coils () in the decoupling circuit () are interlaced to achieve mutual decoupling between adjoining coils. Each separate coil () includes a pair of spaced parallel main conductors () located on opposite sides of a cylindrical space () enclosed by the coils (). The decoupling base () comprises two meandering conductor bases () which are interlaced. Orthogonal main conductors () of the coil () share a common conductor base (). The multiple crossings of the paths of the conductor bases () reduces mutual coupling effects.

Coil decoupling

A portable device is used to measure exposure to magnetic fields and/or exposure to changes of magnetic field. The device () includes a first sensor () for measuring instantaneous magnetic field strength, and a second sensor () which is located adjacent to, and orientated in the same direction as, the first sensor for providing an output indicative of the time rate of change of the magnetic field. An integrator () integrates the rate of change output from the second sensor () over time to derive relative changes in the magnetic field. A processor () is connected to the outputs of at least the first sensor and the integrator. The processor selectively provides an indication of field strength from the output of the first sensor if the output is within the normal operating range of the first sensor, or otherwise from the integrator. A memory () is connected to the output of the second sensor () to store cumulative exposure to changes in the magnetic field. Three pairs of first and second sensors may be orientated in respective orthogonal directions.

Magnetic field dosimeter

A method and apparatus for ameliorating high-field image distortion in magnetic resonance imaging of tissue. Two separate scans of a target region are taken with different phase and amplitude values for each scan. The phase and amplitude values of each scan are selected to be complimentary so as to provide scans that have improved SNR when averaged using, for example, sum-of-squares averaging.

Phased array coil for MRI

A radio frequency (RF) coil array is used in resonance imaging and/or analysis of a subject located within a cylindrical space in which a magnetic field is operatively applied in an axial direction (z). The coil array comprises a plurality of coil elements () angled relative to each other about the axis of the cylindrical space, each coil element having a pair of main conductors extending generally parallel to the direction of the magnetic field and located on diametrically opposite sides of the cylindrical space, and a pair of connection conductors connected between respective ends of the main conductors. Each coil element has its maximum sensitivity near the centre of the cylindrical space, so that the subject under study is located in a region of maximum sensitivity.

Coil array for magnetic resonance imaging

Magnetic resonance systems are provided which employ a shielded, asymmetric magnet to produce an offset dsv. The magnets include at least a first coil C, which carries current in a first direction, and two coils Cand C, which are located at least in part within the internal envelope Edefined by the first coil and which carry current in an opposite direction to the first coil. The magnets are shielded by a shielding coil C, which carries current in a direction opposite to that of the first coil, and/or a ferromagnetic structure (FS). The magnets can include additional coils, such as a fifth coil Cat the magnet's distal end. The magnets can be used in, for example, orthopedic imaging.

Shielded, asymmetric magnets for use in magnetic resonance imaging

Asymmetric radio frequency (RF) coils for magnetic resonance applications are provided. Also provided are time harmonic methods for designing such coils as well as symmetric coils. In addition, methods for converting complex current density functions into discrete capacitive and inductive elements are provided.

Asymmetric radio frequency coils for magnetic resonance

Bi-planar coil assemblies are disclosed which have DSV's whose centers are offset by distances D from the origins of x,y,z-coordinate systems, where said origins of x,y,z-coordinate systems are coincident with the geometric centers of the coils. The distances D can be of the order of 10-20 centimeters or more. The bi-planar coil assemblies can be used in MRI applications to reduce the feeling of claustrophobia experienced by some subjects. The assemblies also can facilitate the imaging of various joints, including the wrist, elbow, ankle, or knee.

Bi-planar coil assemblies for producing specified magnetic fields

Asymmetric, compact superconducting magnets for magnetic resonance imaging are provided. The magnets have a homogeneous region (the 'dsv') which can be located close to one end of the magnet so as to reduce the sensation of claustrophobia experienced by patients undergoing MRI procedures. The magnets can be designed using a hybrid process in which current density analysis is performed to obtain an initial coil configuration which is then refined using non-linear optimization techniques to obtain a final coil configuration. The hybrid method can incorporate various constraints, including, the location and size of the dsv, the uniformity and strength of the Bfield, stray field strengths outside of the superconducting magnet, and field strengths within the magnet's coils. The hybrid technique can also be used to design compact symmetric superconducting magnets.

Asymmetric superconducting magnets for magnetic resonance imaging

Asymmetric, compact non-superconducting magnets for magnetic resonance imaging are provided. The magnets have a homogeneous region (the &ldquo;dsv&rdquo;) which can be located close to one end of the magnet so as to reduce the sensation of claustrophobia experienced by patients undergoing MRI procedures. The magnets can be designed using a hybrid process in which current density analysis is performed to obtain an initial coil configuration which is then refined using non-linear optimization techniques to obtain a final coil configuration. The hybrid method can incorporate various constraints, including, the location and size of the dsv, the uniformity and strength of the B field, stray field strengths outside of the non-superconducting magnet, and field strengths within the magnet's coils. The hybrid technique can also be used to design compact symmetric non-superconducting magnets.

Growing community of inventors

Wilston, Australia

Stuart Crozier