Abstract: A metamaterial (MTM) slab for a Magnetic Resonance Imaging (MRI) system passively interacts with a field generated by a transmit device to improve homogeneity of the field, specific absorption rate, and/or strength of the field. The MTM slab may also be connected to RF receive circuitry at one or more ports to act as a receiver for the MRI. The MTM slab may comprise a first layer generally defining a surface and a second layer offset from the surface generally defined by the first layer, the first layer and the second layer interacting to form a 2D transmission line supporting radio frequency (RF) current along the surface in a first direction and in a second direction transverse to the first direction, the first layer and the second layer being connected via linking capacitors.

Abstract: A liner for a bore of an MRI scanner having a magnetic field. The liner comprises: plural conductors extending circumferentially within a liner region of the bore; circumferential impedances on the plural conductors; and radial impedances connecting the plural conductors to a radially outer conductive structure.

Abstract: A metamaterial liner for an MRI bore. The metamaterial liner may cover only a portion of the MRI bore, allowing travelling wave excitations within the lined portion. By restricting the waves to the lined portion, improved signal to noise ratio may be provided. The lined length may be adjustable, for example by forming the metamaterial liner of removable annular segments. A method is provided of adjusting the length of the lined portion by removing metamaterial segments. The segments may be included in interchangeable modules. The MRI liner is suitable for any magnetic field strength, and in particular may provide improved signal to noise at reduced technical difficulty at magnetic field strengths between conventional field strengths suitable for a birdcage coil and conventional travelling wave field strengths.

Abstract: A metamaterial liner for an MRI bore. The metamaterial liner may cover only a portion of the MRI bore, allowing travelling wave excitations within the lined portion. By restricting the waves to the lined portion, improved signal to noise ratio may be provided. The lined length may be adjustable, for example by forming the metamaterial liner of removable annular segments. A method is provided of adjusting the length of the lined portion by removing metamaterial segments. The segments may be included in interchangeable modules. The MRI liner is suitable for any magnetic field strength, and in particular may provide improved signal to noise at reduced technical difficulty at magnetic field strengths between conventional field strengths suitable for a birdcage coil and conventional travelling wave field strengths.

Abstract: A liner for a bore of a waveguide is provided. The liner as an aperture passing through it and is formed of a metamaterial that has a relative electrical permittivity that is negative and near zero. When the liner is installed in the waveguide, it lowers the cutoff frequency of the waveguide while allowing the waveguide to remain hollow. This liner can be used in the bore of an MRI machine to lower the cutoff frequency of the bore of the MRI machine to allow the MRI machine to operate using waves having a lower frequency that if the liner was not used.

Abstract: A method for acquiring an image or spectrum of a subject or object residing within the magnetic field of a magnetic resonance apparatus, comprises the steps of: executing a predetermined pulse sequence for applying gradient magnetic fields and for coupling in electromagnetic excitation pulses to induce nuclear magnetic resonance within the subject or object; detecting an electromagnetic signal resulting from said magnetic resonance; and constructing at least one image or magnetic resonance spectrum of said subject or object from said detected electromagnetic signal. According to the invention, said coupling in of the electromagnetic excitation pulse and/or said detecting of the electromagnetic signal are carried out substantially by means of travelling electromagnetic waves.

Abstract: A magnetic field probe comprises a sample that exhibits magnetic resonance at an operating frequency, an electrically conductive structure surrounding the sample for receiving a magnetic resonance signal therefrom, and a solid jacket encasing the sample and the conductive structure. The jacket is made of a hardened two-component epoxy system containing a paramagnetic dopant dissolved therein, with the concentration of the dopant being chosen such that the jacket has a magnetic susceptibility that is substantially identical to the magnetic susceptibility of the conductive structure.

Abstract: A method for acquiring an image or spectrum of a subject or object residing within the magnetic field of a magnetic resonance apparatus, comprises the steps of: executing a predetermined pulse sequence for applying gradient magnetic fields and for coupling in electromagnetic excitation pulses to induce nuclear magnetic resonance within the subject or object; detecting an electromagnetic signal resulting from said magnetic resonance; and constructing at least one image or magnetic resonance spectrum of said subject or object from said detected electromagnetic signal. According to the invention, said coupling in of the electromagnetic excitation pulse and/or said detecting of the electromagnetic signal are carried out substantially by means of travelling electromagnetic waves.

Abstract: A magnetic field probe comprises a sample (4) that exhibits magnetic resonance at an operating frequency, an electrically conductive structure (8) surrounding the sample for receiving a magnetic resonance signal therefrom, and a solid jacket (12) encasing the sample and the conductive structure. The jacket is made of a hardened two-component epoxy system containing a paramagnetic dopant dissolved therein, with the concentration of the dopant being chosen such that the jacket has a magnetic susceptibility that is substantially identical to the magnetic susceptibility of the conductive structure.

Abstract: A coil assembly for magnetic resonance imaging comprises a sheet (2) of flexible and stretchable dielectric material and at least one electrically conducting coil (4a, 4b) for receiving and/or emitting a radio frequency signal. The coil is attached to and extends along a face of the flexible sheet. At least part of the coil is made of a ribbon shaped braided conductor (6) that is arranged in substantially flat contact with the face.

Abstract: A coil assembly for magnetic resonance imaging comprises a sheet (2) of flexible and stretchable dielectric material and at least one electrically conducting coil (4a, 4b) for receiving and/or emitting a radio frequency signal. The coil is attached to and extends along a face of the flexible sheet. At least part of the coil is made of a ribbon shaped braided conductor (6) that is arranged in substantially flat contact with the face.

Abstract: A novel magnetic resonance (MR) imaging or spectroscopy method is presented, in which a main magnetic field is generated in an object by a main magnet and superimposed magnetic fields and adiofrequency fields are generated according to an MR sequence for forming images or spectra. Object signals are acquired from the object with at least one object detector during execution of the MR sequence. Further, additional data are acquired from at least one monitoring field probe positioned in the vicinity of and surrounding the object, during execution of the MR sequence. The additional data from the monitoring field probes are used for adjusting the MR sequence such as to correct for imperfections in the field response of the object detectors, and the additional data from the monitoring field probes are used in conjunction with the object signals for reconstruction of the images or spectra.

Abstract: A novel magnetic resonance (MR) imaging or spectroscopy method is presented, in which a main magnetic field is generated in an object by a main magnet and superimposed magnetic fields and adiofrequency fields are generated according to an MR sequence for forming images or spectra. Object signals are acquired from the object with at least one object detector during execution of the MR sequence. Further, additional data are acquired from at least one monitoring field probe positioned in the vicinity of and surrounding the object, during execution of the MR sequence. The additional data from the monitoring field probes are used for adjusting the MR sequence such as to correct for imperfections in the field response of the object detectors, and the additional data from the monitoring field probes are used in conjunction with the object signals for reconstruction of the images or spectra.

Abstract: A shielded birdcage-type radiofrequency (RF) resonance coil having a non-circular cross-sectional shape corresponding to a Cassinian oval. The placement of longitudinal conducting elements in the former of the coil is determined numerically by conformal mapping of the equally distributed positions of the conductors in a circular coil onto a Cassinian oval.