Abstract: In some aspects, a downhole nuclear magnetic resonance (NMR) tool includes a magnet assembly and an antenna assembly. The NMR tool can operate in a wellbore in a subterranean region to obtain NMR data from the subterranean region. The magnet assembly produces a magnetic field in a volume about the wellbore. The antenna assembly produces excitation in the volume and acquires an azimuthally-selective response from the volume based on the excitation. The antenna assembly can include a transversal-dipole antenna and a monopole antenna.

Abstract: The flow-through NMR analyzer comprises: a solution feeding pipe for flowing a sample; a superconducting magnet that encloses a housing space, which is surrounded by a side wall of the solution feeding pipe, around an axis of the solution feeding pipe such that a static magnetic field is generated along the axis of the solution feeding pipe; a vacuum container which houses the superconducting magnet in a cooled state and which encloses the housing space around the axis of the solution feeding pipe; and an RF coil which applies high-frequency electromagnetic waves to the sample inside the housing space and which detects an NMR signal from the sample. The RF coil is integrally formed with the side wall of the solution feeding pipe in a region of the solution feeding pipe that is enclosed by the superconducting magnet and the magnetic field correcting coil.

Abstract: When a portion of a structure enclosing a local coil is inserted in a homogeneity region of a basic magnetic field of a magnetic resonance system, the local coil is operable to receive magnetic resonance signals originating from a specific detection zone for the local coil arrangement. At least one conductor is arranged in the structure. Field lines of a compensation magnetic field generated by current encircling the conductor form a compensation magnetic field angle with the basic magnetic field in an edge area of the detection zone. Return conductors complete an electric circuit containing the conductor and extend in the direction of the basic magnetic field and/or are arranged such that field lines of an interfering magnetic field counteracting the compensation magnetic field encircle the respective return conductor and form an interfering magnetic field angle with the basic magnetic field in the edge area.

Abstract: In a method for distortion correction in spiral magnetic resonance imaging, a first MR data set is acquired by scanning raw data space along a spiral trajectory beginning at a first point. A first complex MR image is determined from the first MR data set, which includes first phase information for image points of the first MR image. A second MR data set is acquired by scanning raw data space along the spiral trajectory beginning at a second point that differs from the first point. A second complex MR image is determined from the second MR data set, which includes second phase information for image points of the second MR image. A geometric distortion for image points of the first or second MR image is determined from the first and second phase information, for example with a PLACE method.

Abstract: Magnetic resonance reconstruction includes motion compensation. Inverse-consistent non-rigid registration is used to determine motion between shots. The motion is incorporated into reconstruction. The incorporation compensates for the motion resulting from the period over which the MR data is acquired.

Abstract: A multichannel RF switching device of an embodiment has a connector in which all or some of a plurality of terminals are configured to be connected to a plurality of coil elements, a matrix switch having a plurality of input ports arranged in a line and a plurality of output ports arranged in a line, and a wiring portion connecting the respective terminals configured to be connected to the plural coil elements with a plurality of input ports in use included in the plural input ports one-on-one, the input ports in use amounting to fewer than the total number of the input ports, wherein the wiring portion connects the respective terminals with the input ports in use one-on-one in such a way that a separation between adjacent two of all or some of the input ports in use is larger than a separation between adjacent two of the input ports.

Abstract: An apparatus for detecting magnetic resonance signals from a target, comprises a magnetic resonance sensor for responding to magnetic resonance signals from a target, and a shield member electrically isolated from the magnetic resonance sensor, the shield member being positioned relative to the magnetic resonance sensor such that when the magnetic resonance sensor faces the target, the shield member is behind the magnetic resonance sensor to at least partially shield the magnetic resonance sensor from magnetically coupling with sources other than the magnetic resonance signals.

Abstract: In a magnetic resonance (MR) method and system for correction of phase information in MR images of a predetermined volume segment of an examination subject, a basic magnetic field is applied and MR data of the predetermined volume segment are acquired and evaluated such that phase information is calculated for each image element of the predetermined volume segment. A navigator signal is acquired that detects an unintentional change of the basic magnetic field that is caused by movements of the examination subject or by the magnetic resonance system itself. The phase information is corrected with this navigator signal.

Abstract: A magnetic resonance sequence includes a repetitively applied radiofrequency pulse capable of causing a specific absorption rate (SAR) hot spot. The composition of the repetitive pulse is varied to generate versions of the repetitive pulse such that the SAR hot spot changes locations with subsequent applications of the repetitive pulse. To generate versions of the pulse, a pilot scan is performed to generate a patient model. A simulation of the SAR response to each of the versions of the repetitive pulse is performed to determine the location of SAR hot spot(s). A plurality of versions of the repetitive pulse is selected to be used in the magnetic resonance sequence.

Abstract: Provided is a total electrical nuclear-spin polarization device that is applicable to many narrow-gap semiconductor two-dimensional quantum structures such as InSb with a large g-factor and with a mobility having a normal value. A nuclear-spin polarization device 1 creates a state where the Landau-level separation and the Zeeman-level separation in a sample are equal to each other in a magnetic field, thereby crossing different spin states, and detects nuclear-spin polarization from a resistance change at the crossing point caused by the nuclear-spin polarization.

Abstract: A method for time synchronization of various components of a magnetic resonance system includes generating a series of amplitude-modulated radio-frequency pulses and associated gradient fields to deflect the magnetization of a slice detecting at least two spin signals, determining a phase difference between two of the spin signals, processing the phase difference in order to determine at least one time shift between two of the following variables that are generated by different components of the magnetic resonance system, an envelope of the amplitude-modulated radio-frequency pulses, a radio-frequency portion of the amplitude-modulated radio-frequency pulses, and one or more gradient fields, and synchronizing the associated components of the magnetic resonance system depending on the at least one time shift.

Abstract: A device for power measurement for the purposes of plausibility checking and/or calibration of a primary power measurement device on a power amplifier of a magnetic resonance device is provided. The device includes a circulator arranged between an output of the power amplifier and a switching device for connection of the power amplifier to a transmit antenna. A first input of the circulator is connected to the output of the power amplifier, a second input of the circulator is connected to the switching device, and a third input of the circulator is connected to a secondary power measurement device configured for measurement of a signal reflected on the open switching device or the transmit antenna.

Abstract: An object is to correct a magnetic field caused by an eddy current, which is generated due to application of a gradient magnetic field, not only in the application direction of the gradient magnetic field but also in a direction different from the application direction of the gradient magnetic field. In the present invention, in order to achieve this object, a compensation magnetic field which compensates for an eddy current magnetic field generated in each of an application direction of a test gradient magnetic field and a direction different from the application direction in each direction is calculated using the test gradient magnetic field. When generating an arbitrary gradient magnetic field, a compensation magnetic field which compensates for an eddy current magnetic field according to application of an arbitrary gradient magnetic field on the basis of the measured eddy current magnetic field in each direction is generated together with the arbitrary gradient magnetic field.

Abstract: The present embodiments include an antenna circuit that is adapted to supply and/or read out a plurality of antenna elements of an antenna assembly of a magnetic resonance imaging system. The antenna elements are decoupled by phase shifter elements and supplied with signals by the phase shifter elements. The antenna circuit may also be used to detect signals that are received by the antenna elements.

Abstract: A radio frequency (RF) body coil includes a first end ring, a second end ring, a plurality of rungs connected between the first and second end rings, at least one shim holder coupled to the first end ring, and a RF shim configured to be at least partially inserted within the shim holder, the RF shim being repositionable within the shim holder to vary an operational frequency of the RF body coil. A magnetic resonance imaging system and a method of tuning the RF body coil are also described.

Abstract: An RF coil device and an MRI apparatus allowing a connection relationship between input RF channels and output RF channels to be controlled by a smaller number of switch elements are provided. The RF coil device includes multiple coil segments and a multi-selection switch. Input terminals of the multi-selection switch are each connected to a different coil segment. An output terminal of the multi-selection switch leads to an RF output channel. A control terminal of the multi-selection switch is used to receive a control signal so as to select a coil segment for connection to the output terminal. Multiple coil segments connected to the input terminals are not in consecutive positions, and the number of coil segments by which any two of the multiple coil segments are spaced apart is no fewer than the maximum number of coil segments required for one MRI imaging less 1. The MRI apparatus includes the RF coil device.

Abstract: A method is disclosed for calculating an MR image of a target layer from an examination object, wherein the MR image is calculated using iterative reconstruction. In at least one embodiment, the method includes: acquiring MR data from an initial layer of the examination object, determining information produced by the examination object from the acquired MR data of the initial layer, determining a penalty term from the information produced by the examination object, and performing the iterative reconstruction of the MR image for the target layer taking into account the determined penalty term.

Abstract: In an imaging method and device for water/fat separation in MRI using a two-point Dixon FSE sequence, each refocusing RF pulse corresponds to two readout gradients of the same polarity, each being center-divided into a smaller rear part and a larger front part, and one rephasing gradient of opposite polarity. In running the FSE sequence, each echo signal acquired is subjected to an FFT, to reconstruct an image with water and fat in phase and an image with water and fat in opposed phases. Data of each echo signal are subjected to a partial Fourier transform; and the in-phase water/fat image and the opposite-phase water/fat image are subjected to a water/fat separation algorithm, to obtain a pure water image and a pure fat image.

Abstract: There is provided a technique for securing a large examination space in a tunnel type MRI device without inviting increase of manufacturing cost and without significantly reducing irradiation efficiency or uniformity of the irradiation intensity distribution in an imaging region. Between rungs of a partially cylindrical RF coil, which coil corresponds to a cylindrical RF coil of which part is removed, there are disposed half-loops generating magnetic fields, which are synthesized with magnetic fields generated by loops constituted by adjacent rungs of the partially cylindrical RF coil and rings connecting the rungs to generate a circularly polarized or elliptically polarized magnetic field. Further, high-frequency signals of the same reference frequency having a desired amplitude ratio and phase difference are supplied to the partially cylindrical RF coils and half-loops.

Abstract: A method for magnetic resonance imaging (MRI) using a radial cone k-space trajectory is provided. The radial cone k-space trajectory is defined by the application of a radial magnetic field gradient and one or more oscillating magnetic field gradients. The amplitude of the radial magnetic field gradient increases with time before decreasing with time. While the amplitude of the radial magnetic field gradient is decreasing, the one or more oscillating magnetic field gradients are applied. As a result, the radial cone k-space trajectory is one that is oriented along an axis and that extends outward from an origin along a substantially radial trajectory before extending outward from the origin while circumscribing a conical volume having a radius that increases nonlinearly with distance from the origin.