Abstract: MRI techniques provide robust imaging in the presence of inhomogeneity in the B1 (RF) and/or B0 magnetic fields. The techniques include using a magnetization prep sequence that includes an adiabatic half passage (AHP) followed by a spin-lock pulse, followed by a reverse AHP, after which a data acquisition sequence can be applied. The AHP and reverse AHP can have amplitude and frequency modulated to sweep through a region of frequency space. The RF amplitude of the AHP and reverse AHP can be designed to be equal to the spin-lock amplitude. Quantification of a magnetization relaxation parameter (e.g., T1rho) can use a modified relaxation model that accounts for relaxation effects during the reverse AHP. A dual-acquisition technique in which the reverse AHP of the second magnetization prep sequence has opposite frequency modulation to the reverse AHP of the first magnetization prep sequence can also be used.

Abstract: In a method and magnetic resonance imaging apparatus having a scanner that for acquires a magnetic resonance dataset, a magnetic resonance sequence is provided to a computer and is converted in the computer into a digital sequence execution signal that includes a target gradient waveform in the form of a time-discrete target gradient signal the computer calculates a pre-GIRF gradient signal by applying a digital pre-emphasis filter to the target gradient signal. The computer transmits the pre-GIRF gradient signal to the magnetic resonance system scanner and) the scanner executes the digital sequence execution signal containing the pre-GIRF gradient signal in order to acquire magnetic resonance raw data.

Abstract: A system and method is provided for acquisition of magnetic resonance fingerprinting (“MRF”) data that includes determining a non-locally sequential sampling pattern for a Cartesian grid of k-space, performing a series of sequence blocks using acquisition parameters that vary between sequence blocks to acquire MRF data from a subject using the Cartesian grid of k-space and the determined non-locally sequential sampling pattern, assembling the MRF data into a series of signal evolutions, comparing the series of signal evolutions to a dictionary of known signal evolutions to determine tissue properties of the subject, and generating a report indicating the tissue properties of the subject.

Abstract: A computer that determines coefficients in a representation of coil sensitivities and MR information associated with a sample is described. During operation, the computer may acquire MR signals associated with a sample from the measurement device. Then, the computer may access a predetermined set of coil magnetic field basis vectors, where weighted superpositions of the predetermined set of coil magnetic field basis vectors using the coefficients represent coil sensitivities of coils in the measurement device, and where the predetermined coil magnetic field basis vectors are solutions to Maxwell's equations. Next, the computer may solve a nonlinear optimization problem for the MR information associated with the sample and the coefficients using the MR signals and the predetermined set of coil magnetic field basis vectors.

Abstract: A method for magnetic resonance fingerprinting with out-of-view artifact suppression includes acquiring MRF data from a region of interest in a subject. The MRF data is acquired using a non-Cartesian, variable density sampling trajectory. The MRF data includes data from within a desired field-of-view and data from outside the desired field-of-view. The method also includes generating a set of coil images based on the MRF data with a field-of-view larger than the desired field-of-view, determining a noise covariance based on the MRF data from outside the desired field-of-view, generating a coil combined image using an adaptive coil combination determined based on the noise covariance, applying the adaptive coil combination to the MRF data to grid each frame of the MRF data and generate MRF data with out-of-view artifact suppression. The method also includes identifying at least one property of the MRF data and generating a report.

Abstract: A method is disclosed for phase contrast magnetic resonance imaging (MRI) comprising: acquiring phase contrast 3D spatiotemporal MRI image data; inputing the 3D spatiotemporal MRI image data to a three-dimensional spatiotemporal convolutional neural network to produce a phase unwrapping estimate; generating from the phase unwrapping estimate an integer number of wraps per pixel; and combining the integer number of wraps per pixel with the phase contrast 3D spatiotemporal MRI image data to produce final output.

Abstract: Methods, devices, systems and apparatus for dynamic imaging based on echo planar imaging (EPI) sequence are provided. In one aspect, a method includes: obtaining first pre-scanned k-space data by performing a pre-scan for a subject based on a first EPI sequence and pre-scanning parameters, obtaining a pre-scanned image and second pre-scanned k-space data according to the first pre-scanned k-space data, performing a dynamic scan for the subject based on a second EPI sequence and dynamic scanning parameters to generate dynamically-scanned k-space data associated with each of a plurality of dynamic periods in the dynamic scan, and for each of the dynamic periods, generating a residual image according to the dynamically-scanned k-space data of the dynamic period and the second pre-scanned k-space data, and adding the pre-scanned image and the residual image to obtain a dynamic image of the dynamic period.

Abstract: A therapeutic apparatus comprising a radiotherapy apparatus for treating a target zone and a magnetic resonance imaging system for acquiring magnetic resonance imaging data. The radiotherapy apparatus comprises a radiotherapy source for directing electromagnetic radiation into the target zone. The radiotherapy apparatus is adapted for rotating the radiotherapy source at least partially around the magnetic resonance magnet. The magnetic resonance imaging system further comprises a radio-frequency transceiver adapted for simultaneously acquiring the magnetic resonance data from at least two transmit-and-receive channels. The therapeutic apparatus further comprises a processor and a memory containing machine executable instructions for the processor.

Abstract: A method of magnetic resonance (MR) imaging of an object includes: generating MR signals by subjecting the object to a number N of shots of a multi-echo imaging sequence comprising multi-slice RF pulses for simultaneously exciting two or more spatially separate image slices, with a phase offset in the slice direction being imparted to the MR signals; acquiring the MR signals that are received in parallel via a set of at least two RF coils having different spatial sensitivity profiles; and reconstructing a MR image for each image slice from the acquired MR signals using a parallel reconstruction algorithm, wherein the MR signal contributions from the different image slices are separated on the basis of the spatial encodings of the MR signals according to the spatial sensitivity profiles of the RF coils and of the phase offsets attributed to the respective image slices and shots.

Abstract: According to one embodiment, a magnetic resonance imaging apparatus includes processing circuitry. The processing circuitry acquires a first resonance frequency distribution of a first tissue and a second resonance frequency distribution of a second tissue which is different from the first tissue. The processing circuitry calculates a center frequency of a frequency-selective pulse that suppresses or emphasizes either one of the first tissue and the second tissue in accordance with the first and second resonance frequency distributions. The processing circuitry collects a magnetic resonance signal after the frequency-selective pulse is applied at the calculated center frequency.

Abstract: The present invention is directed to inductively feeding a RF coil (9) for magnetic resonance imaging (MRI), and in particular to a system comprising a RF coil (9) for magnetic resonance imaging and at least one feeding coil (14) for inductively feeding the RF coil (9) with an RF signal, and further to a method for inductively feeding a RF coil (9) for magnetic resonance imaging with at least one RF signal. According to the invention, in this system, the at least one feeding coil (14) is configured and arranged for feeding the RF signal into a conductive coil element (10) of the RF coil (9) at a first position and at a second position, the first position being different from the second position, wherein the direction of the magnetic field of the RF signal at the first position is different from the magnetic field of the RF signal at the second position. In this way, the invention provides for an inductive RF feeding of a resonator which can be achieved in a compensated way, i.e.

Abstract: The invention also relates to a MRI apparatus for obtaining images of a target volume of a human and/or animal subject using magnetic resonance imaging (MRI), said MRI apparatus at least comprising: a housing defining a target area for accommodating said human and/or animal subject; at least one main magnet unit and at least one magnetic gradient unit for applying—during use—one or more magnetic field gradients along three independent orthogonal spatial axes in said target area, as well as at least one radiofrequency (RF) pulse generation unit for applying one or more sets of RF pulses towards said target area; a RF receiving unit for acquiring MRI signals possibly having multi-channel spatially sensitive characteristics; and a computer processing unit for processing said acquired MRI signals and for producing said magnetic resonance image data.

Abstract: A system and method generate a synthetic image with switchable image contrast components for a biological object. The method includes: a) using first and second quantitative MRI acquisition techniques for measuring a value of first or second quantitative parameters Q1, Q2 for the biological object and generating first and second quantitative maps, the first and second quantitative MRI acquisition techniques generate first and second contrast-weighted images; b) using the first and second quantitative maps, and the first and second contrast weighted images as inputs in a model configured for generating a synthetic image M with arbitrary sequence parameters P1, P2, P3, according to: M=|Cif(Q1,Q2,P1,P2,P3)| wherein Ci with i=1, 2, are contrast components for the generation of the synthetic image M coming from respectively the first (i=1) and second (i=2) contrast-weighted images (i=1) and f is a function of Q1, Q2, P1, P2 and P3; and c) displaying the synthetic image M.

Abstract: A magnetic resonance imaging system (100) for acquiring magnetic resonance data (141) from an imaging zone (108) includes a memory (134, 136) for storing machine executable instructions (150, 152, 154, 156) and pulse sequence commands (140). The pulse sequence commands cause the magnetic resonance imaging system to provide at least one spatially selective saturation pulse (408, 410) to at least one selected volume (124, 124?) that is at least partially outside of a region of interest (123) and within the imaging zone. The magnetic resonance imaging system performs a non-selective inversion (412) of spins in the region of interest followed by a readout (414) of the magnetic resonance data which is reconstructed (202) into an image (142).

Abstract: A system and method is provided for correcting receiver bias during quantitative proton density mapping with magnetic resonance fingerprinting (MRF). The method comprises acquiring MRF data from a region of interest in a subject by performing a pulse sequence using a series of varied sequence blocks to elicit a series of signal evolutions. The method further comprises comparing the MRF data to a MRF dictionary to simultaneously map proton density and another tissue property from the region of interest, the proton density map having a proton density signal and a receiver sensitivity profile signal. The method also includes quantifying the proton density signal and the receiver sensitivity profile signal using parameters provided by the proton density map and the tissue property map, and generating a quantitative map from the region of interest based on the proton density signal.

Abstract: A new method is developed for ultrafast, high-resolution magnetic resonance spectroscopic imaging (MRSI) using learned spectral features. The method uses Free Induction Decay (FID) based ultrashort-TE and short-TR acquisition without any solvent suppression pulses to generate the desired spatiospectral encodings. The spectral features for the desired molecules are learned from specifically designed “training” data by taking into account the resonance structure of each compound generated by quantum mechanical simulations. A union-of-subspaces model that incorporates the learned spectral features is used to effectively separate the unsuppressed water/lipid signals, the metabolite signals, and the macromolecule signals. The unsuppressed water spectroscopic signals in the data can be used for various purposes, e.g., removing the need of additional auxiliary scans for calibration, and for generating high quality quantitative tissue susceptiability mapping etc.

Abstract: A magnetic resonance fingerprinting (MRF) method for determining parameter values in pixels of an examination object can use a magnetic resonance system with, for example, a constant magnetic field strength (e.g. of less than 1.5 tesla or a constant magnetic field strength of less than 0.5 tesla). The MRF method can be adapted for conditions that prevail with such low-field magnetic resonance systems, thus enabling the parameter values to be advantageously determined efficiently while simultaneously maintaining a high degree of quality.

Abstract: In a method and apparatus for characterizing an obstacle within an examination object using a medical image data set by the use of a database containing at least one data class, a trained artificial neural network defines and develops relationships between different obstacles, features and medical imaging data sets. A data entry of a data class is assigned by the neural network to the obstacle within the examination object and the obstacle within the examination object is characterized in an electronic output by this data entry.

Abstract: An image corrected for body motion with high accuracy in a short time when performing retrospective body motion correction on an MRI image is provided, and the time from imaging to image display is reduced. A body motion corrector of an MRI apparatus has a weighting factor calculator that calculates a three-dimensional weighting factor based on signals received by multi-channel receive coils. A processing space converter converts three-dimensional frequency space data of a measurement signal and the three-dimensional weighting factor respectively into hybrid space data and a two-dimensional weighting factor. A synthesized signal calculator calculates a synthesized signal by convolution integration of the hybrid space data and the two-dimensional weighting factor; and a body motion position detector detects a body motion occurrence position in the hybrid space from the hybrid space data and the synthesized signal.

Abstract: A coil assembly includes: a radio frequency (RF) coil operable to be placed over a portion of a subject; a quarter-wave transformer coupled to the RF coil and configured to transform a characteristic impedance of the RF coil; and a diode placed behind the quarter-wave transformer and away from the RF coil, wherein the diode is operable to: (i) when the diode is forward biased, the diode turns the quarter-wave transformer into an open circuit such that the power amplifier drives the RF coil with sufficient electrical power for the RF coil to transmit an RF pulse into the portion of the subject; and (ii) when the diode is provided zero or reverse bias, the diode turns the quarter-wave transformer into a short circuit such that the RF coil is detuned from a Lamor frequency of nuclei of interest immersed in the main magnet.

Abstract: A method of measuring a tissue parameter such as proteoglycan content and other relevant tissue parameters, e.g. tissue pH, in a tissue or an organ of a subject includes generating first and second frequency magnetic resonance data using T1? scans at different frequencies, wherein the frequencies are symmetric. The method also includes combining the first frequency magnetic resonance data and the second frequency magnetic resonance data to remove a number of contributions from a number of relaxation mechanisms other than chemical exchange, thereby obtaining chemical exchange-specific magnetic resonance data indicative of the tissue parameter in the tissue or the organ. The chemical exchange-specific magnetic resonance data may be used to measure the proteoglycan content in the tissue or organ.

Abstract: The invention relates to a method of MR imaging of an object. It is an object of the invention to enable MR imaging using the stack-of-stars acquisition scheme with an enhanced control of the contrast of the reconstructed MR image. The method of the invention comprises the steps of: a) generating MR signals by subjecting the object (10) to a number of shots of a multi-echo imaging sequence comprising RF pulses and switched magnetic field gradients, wherein a train of echo signals is generated by each shot; b) acquiring the echo signals according to a stack-of-stars (i.e.

Abstract: Provided are an ultra-low field nuclear magnetic resonance device and a method for measuring an ultra-low field nuclear resonance image. The ultra-low field nuclear magnetic resonance device includes an AC power supply configured to supply a current to a measurement target in such a manner the current flows to the measurement target, magnetic field measurement means disposed adjacent to the measurement target, and measurement bias magnetic field generation means configured to apply a measurement bias magnetic field corresponding to a proton magnetic resonance frequency of the measurement target. A vibration frequency of the AC power supply matches the proton magnetic resonance frequency of the measurement target, and the magnetic field measurement means measures a nuclear magnetic resonance signal generated from the measurement target.

Abstract: A method for the magnetic resonance examination of a measurement object is described, in which a measurement sequence is used in which the magnetic resonance response to the transmitted signal during transmission is measured. It is provided that a correction signal corresponding to the transmitted signal be generated and be used for correction of the response signal. To this end, the correction signal is modulated by a phase value and an amplitude value. The phase value and the amplitude value are automatically and iteratively customized for optimum correction of the response signal by an optimization method using a respective present state value of the measurement signal. Further, a radio-frequency unit (1) is described that can be used to carry out the method according to the invention.

Abstract: A magnetic resonance imaging (MRI) system, comprising a magnetics system having a plurality of magnetics components configured to produce magnetic fields for performing magnetic resonance imaging, electromagnetic shielding provided to attenuate at least some electromagnetic noise in an operating environment of the MRI system, and an electrical conductor coupled to the electromagnetic shielding and configured to electrically couple to a patient during imaging of the patient by the MRI system. The magnetics system may include at least one permanent B0 magnet configured to produce a B0 magnetic field for an imaging region of the MRI system. The B0 magnetic field strength may be less than or equal to approximately 0.2 T.

Abstract: A fat saturation method for a magnetic resonance imaging system having a main magnet providing a magnetic field B0 The method includes: driving a shim coil assembly with a first set of shimming currents to sufficiently alter a B0 field inhomogeneity of the magnetic field B0 within a region that includes a first imaging volume of interest such that water saturation inside the region is reduced from before the first set of shimming currents are applied; applying a fat saturation pulse to the region; identifying the first imaging volume of interest from the region; driving the shim coil assembly with a second set of shimming currents to alter the B0 field inhomogeneity of the magnetic field B0 within the first imaging volume of interest such that the B0 field inhomogeneity within the first imaging volume of interest is reduced; and obtaining magnetic resonance signals from the first imaging volume of interest.

Abstract: A plurality of stimulations is transmitted to tissue or other material using one or more transmitters. The plurality of signals associated with the excited tissue and the transmitted stimulations are measured. The measured signals are processed to generate field-related quantities, such as B1+ and/or MR signal maps. Field-related quantities are generated also from simulation, by calculating the one or more incident fields from a simulator model of the one or more transmitters and assuming a given distribution of electrical properties in the tissue or other material. Field-related quantities generated from simulation and experimental procedures are compared to each other. The assumed electrical properties distribution is updated and the procedure is repeated iteratively until the difference between simulated and experimental field-related quantities is smaller than a threshold.

Abstract: In a method for generating an MR image of an object, k-space of the MR image is separated into blades. In each blade, parallel k-space lines are provided which are separated in a phase encoding direction (PED). Each blade has a different rotation angle around a common center relative to the remaining blades. A spatial extent of the object is determined. For the blades, the extent of the object in the corresponding PED is determined. A blade specific extent of a field of view (FOV) in the PED is determined for each of the blades based on the corresponding extent of the object in the PED. The extent of the FOV in the PED differs for at least one of the blades from the extent of the remaining blades, and sampling the k-space with the blades with the determined blade specific FOV as determined for each of the blades.

Abstract: An apparatus to provide power for operating at least one gradient coil of a magnetic resonance imaging system. According to some aspects, the apparatus comprises a plurality of power terminals configured to supply different voltages of a first polarity, and a linear amplifier configured to provide at least one output to power the at least one gradient coil to produce a magnetic field in accordance with a pulse sequence, the linear amplifier configured to be powered by one or more of the plurality of power terminals, wherein the one or more of the plurality of power terminals powering the linear amplifier is selected based, at least in part, on the at least one output.

Abstract: A processor controls an MRI system with pulse sequence commands to acquire magnetic resonance data according to a magnetic resonance fingerprinting protocol during multiple pulse repetitions. The pulse sequence commands control the magnetic resonance imaging system to cause gradient induced spin rephasing at least twice during each of the multiple pulse repetitions, and to acquire at least two magnetic resonance signals during each of the multiple pulse repetitions. Each of the at least two magnetic resonance signals is measured during a separate one of the gradient induced spin rephasing. The magnetic resonance data includes the at least two magnetic resonance signals acquired during each of the multiple pulse repetitions. The processor further at least partially calculates a B0-off-resonance map using the magnetic resonance data, and generates at least one magnetic resonance parametric map by comparing the magnetic resonance data with a magnetic resonance fingerprinting dictionary.

Abstract: The present invention relates to a method for performing electrical impedance tomography (EIT) by an MR system, wherein during the MR measurement continuous RF signals for an EIT measurement are emitted by at least one RF coil of the MR system, and continuous RF signals modulated by the object undergoing examination are received by the receiving coils of the MR system. An image of the object undergoing examination is determined, based on the modulated continuous RF signals, by an EIT technique.

Abstract: Methods, systems and circuits evaluate a subject's risk of developing type 2 diabetes using defined mathematical models of short term risk (STR) and longer term risk of progression. The evaluations can stratify risk for patients having the same glucose measurement, particularly those with intermediate or low (normal) fasting plasma glucose (FPG) values. The STR or IR (insulin resistance) model(s) may include an inflammatory biomarker such as an NMR derived measurements of GlycA and a plurality of selected lipoprotein components of at least one biosample of the subject. Embodiments of the invention also provide methods, systems and circuits that generate STR scores as a marker of beta-cell dysfunction or impairment.

Abstract: The present invention relates to orthopaedic implants and has particular relevance to determining the placement of fixation apparatus or devices, such as screws, which are used to fix implants to the bone or bones with which the implants are to be connected. More particularly, the invention relates to a method for determining placement of a fixation apparatus for fixing an orthopaedic implant to bone, and the method comprising: selecting a plurality of fixation locations; using a bone density model to determine bone density associated with each location; and selecting a combination or permutation of the fixation locations dependent on the determined bone density.

Abstract: Described here are systems and methods for producing images of a subject using magnetic resonance imaging (“MRI”) in which data are acquired using a sparse approximate encoding scheme for controlled aliasing techniques. As one example, the sparse approximate encoding can be used for a Wave-CAIPI encoding scheme, which can enable faster image reconstruction using fewer computational resources, in addition to reducing noise in the reconstructed images relative to those reconstructed from data acquired using a Wave-CAIPI encoding scheme without sparse approximate encoding.

Abstract: A method is provided for determining an orientation of nerve fibres relative to a non-physiological electric field. Patient medical image data is acquired, which describes a patient medical image of an anatomical body part of a patient's body. The anatomical body part includes nerve tissue comprising white matter nerve fibres. Diffusion image data is acquired, which describes a diffusion-enhanced image of the anatomical body part. Atlas data is acquired, which describes a spatial distribution of grey value-based tissue classes in a model body part representing a model of the anatomical body part. Based on the patient image data, the diffusion image data, and the atlas data, fibre orientation data is determined. The fibre orientation data describes an orientation of the white matter nerve fibres. Electric field orientation data is acquired, which describes an orientation of the non-physiological electric field.

Abstract: Systems and methods for magnetic resonance imaging (“MRI”) that address the geometric distortions and blurring common to conventional echo planar imaging (“EPI”) sequences, and that provide new temporal signal evolution information across the EPI readout, are described. Echo planar time-resolved imaging (“EPTI”) schemes are described to implement an accelerated sampling of a hybrid space spanned by the phase encoding dimension and the temporal dimension. In general, each EPTI shot covers a segment of this hybrid space using a zigzag trajectory with an interleaved acceleration in the phase-encoding direction. The hybrid space may be undersampled and a tilted reconstruction kernel used to synthesize additional data samples.

Abstract: A magnetic resonance imaging apparatus according to the present embodiment includes processing circuitry and imaging control circuitry. The processing circuitry selects a human body model corresponding to a subject from human body models. The processing circuitry estimates local specific absorption rates (SARs) at evaluation points determined using the selected human body model, based on the selected human body model and an amplitude and/or phase of the RF pulse in an imaging protocol for magnetic resonance imaging scheduled to be performed on the subject. The processing circuitry determines whether or not the estimated local SARs fall below a local reference value. The imaging control circuitry executes the imaging protocol by using an amplitude and phase of the RF pulse which make the local SARs fall below the local reference value.

Abstract: In a method and magnetic resonance apparatus for generating at least one combination image dataset, a first image dataset is acquired with a turbo spin echo sequence, wherein the echo signals are timed so that the spins of two spin species in the region to be examined are in-phase. A second image dataset is acquired with a turbo spin echo sequence, wherein the echo signals are timed so that the spins of two spin species in the region to be examined have opposed phase. The first image dataset and the second image dataset are combined to form a combination image.

Abstract: A magnetic resonance imaging apparatus according to an embodiment includes a processor. The processor acquires a plurality of pieces of k-space data with undersampling in at least one of axes of k-space and in a certain axis different from the axes of k-space. The processor rearranges the pieces of k-space data into a second order different from a first order in which the pieces of k-space data are acquired. The processor performs a reconstruction process on a rearranged k-space data group to generate an image group.

Abstract: The present invention relates to a device and method for reconstructing low-frequency conductivity images using MRI without current injection. In the device according to the present invention, low-frequency conductivity is deduced using high-frequency conductivity obtained using MR-EPT, the calculated directional tensor of ions from the water diffusion tensor in a subject, and the volume fractions and diffusion coefficients of the intracellular/extracellular spaces, and low-frequency conductivity images are reconstructed based on the deduced low-frequency conductivity. According to the present invention, low-frequency conductivity images in a subject to be measured such as the human body and an object may be reconstructed using an MRI device without applying current to the subject.

Abstract: Reference data is acquired by a slice multiplexing technique on the basis of which calibration data is determined and used to separate measurement data that has been acquired in collapsed form also by a slice multiplexing technique from at least two slices and still has to be separated into single-slice measurement data. As a result, both the reference data and the measurement data to be separated are acquired from several slices simultaneously in each case and hence during the same physiological state of motion in each case. This reduces the sensitivity to motion of a separation of the measurement data performed on the basis of the reference data.

Abstract: A method of MR imaging of a body (10) of a patient reduces contrast blurring in PROPELLER imaging combined with multi-echo acquisitions.

Abstract: A method and system for determining a magnetic field map in a MR system based on position of a movable patient support of the MR system are provided, wherein a first resulting field map including position dependent information about a magnetic field distribution in a homogeneity volume including an examination volume of the MR system is provided when the movable patient support is located at a first position, wherein a stationary field map including information about a magnetic field distribution in the homogeneity volume is provided, which is independent of the position of the movable patient support, wherein a position dependent field map including information about a magnetic field distribution in the homogeneity volume mainly influenced by a position of the movable patient support is determined using the stationary field map and the first resulting field map, and wherein a second resulting field map in the homogeneity volume is determined when the movable patient support is located at a second position di

Abstract: An apparatus to provide power for operating at least one gradient coil of a magnetic resonance imaging system. According to some aspects, the apparatus comprises a plurality of power terminals configured to supply different voltages of a first polarity, and a linear amplifier configured to provide at least one output to power the at least one gradient coil to produce a magnetic field in accordance with a pulse sequence, the linear amplifier configured to be powered by one or more of the plurality of power terminals, wherein the one or more of the plurality of power terminals powering the linear amplifier is selected based, at least in part, on the at least one output.

Abstract: In a protocol parameter selection method and corresponding device, when previewing a current sequence in multiple predetermined sequences, a corresponding reference performance index radar chart is displayed in a standard radar chart, according to a reference value of each performance index in multiple performance indices obtained in advance on the basis of the current sequence. The standard radar chart is a radar chart generated using the multiple performance indices as components and using as a standard a standard value of each performance index obtained in advance on the basis of at least one sequence. The method and device also include determining, as a sequence required for scanning, a current sequence selected according to the reference performance index radar chart and a performance index currently of interest.

Abstract: The pericardiocentesis needle is fitted with sensors, such as at least one electrode or at least one magnetic field sensor, and preferably both a proximal and a distal electrodes or multiple magnetic field sensors. These electrodes or other sensors are coupled to an electrophysiology mapping system configured to display cardiac structures on a display. The electrodes or other sensors on the needle cause a position, and preferably also orientation, of the needle, and especially the tip of the needle, to be visualized on a display of the electrophysiology mapping system, in accurate position relative to adjacent cardiac structures. In other embodiments other transcutaneous devices such as dilators and sheaths can be similarly fitted with electrodes or other sensors for visualization of such other devices within a display of an EP mapping system.

Abstract: A circuit for sensing the driving current of a motor, the circuit comprising: a driver configured to generate a driving current for each phase of a multiple-phase motor, the instantaneous sum of all the driving currents being zero; a current sensor for each phase of the multiple-phase motor, each current sensor configured to measure the driving current of that phase and comprising a plurality of current sensor elements arranged with respect to each other such that each current sensor element has the same magnitude of driving current systematic error due to magnetic fields external to the driving current to be measured; and a controller configured to, for each phase of the multiple-phase motor, generate an estimate of the driving current of that phase to be the measured driving current of that phase minus 1/n of the total of the measured driving currents for all phases, n being the number of phases of the multiple-phase motor.

Abstract: A computer-implemented method of building a database of pulse sequences for parallel-transmission magnetic resonance imaging, includes a) for each of a plurality of subjects, determining an optimal sequence for the subject; b) for each subject, computing the values of the or of a different cost or merit function obtained by playing the optimal sequences for all the subjects; c) aggregating the subjects into a plurality of clusters using a clustering algorithm taking the values, or functions thereof, as metrics; d) for each cluster, determining an averaged optimal sequence for the cluster; e) receiving, as input, a set of features characterizing an imaging subject, comprising at least a morphological feature of the subject; f) associating the subject to one pulse sequence of the database based on the set of features using the computer-implemented classifier algorithm; and g) performing magnetic resonance imaging using the pulse sequence.

Abstract: A local shimming system for magnetic resonance imaging and the method thereof, wherein the shimming method comprises the following steps: collecting B0 field map information using two-dimensional gradient echo (301); calculating and evaluating the homogeneity of B0 (302); optimizing the current of each channel shim coil (303); determining whether the minimum standard deviation value of ?f is obtained (304); outputting an optimal current combination values and setting an optimum current value corresponding to each channel of the shim coil on the current control software (305); and testing and evaluating the homogeneity of B0 to achieve the shimming goal (306).

Abstract: Methods and apparatuses for processing MR signal are disclosed herein. An exemplary method comprises: when acquired K-space signals are amplified, assigning a first amplification gain to signals within a first signal region in the K space, and assigning a second amplification gain to signals within a second signal region in the K space.