Patent classifications
G01R33/48
MAGNETIC RESONANCE IMAGING APPARATUS AND CONTROL METHOD THEREOF
Appropriate processing is executed in a method for excluding body motion data and image reconstruction according to a type and a characteristic of a body motion, so as to reduce an influence of the body motion, and prevent deterioration of image quality caused by exclusion of data generated during the body motion. An MRI apparatus includes a processing determination unit that collects k-space data and acquires body motion information from a sensor capable of detecting not only a respiratory motion but also general body motions, analyzes the body motion information obtained by the sensor, and branches and executes processing for subsequent data collection and image reconstruction according to the analysis result. The MRI apparatus determines, based on a temporal characteristic such as a duration and a frequency, and a spatial characteristic of the body motion, particularly a generation pattern in a k-space, body motion data to be excluded, and executes image reconstruction suitable for k-space data after exclusion of the body motion data.
Artefact reduction in magnetic resonance imaging
Techniques for compensating magnetic resonance imaging (MRI) data for artefacts caused by motion of a subject being imaged. The techniques include obtaining spatial frequency data obtained by using a magnetic resonance imaging (MRI) system to perform MRI on a patient, the spatial frequency data including first spatial frequency data and second spatial frequency data; determining a transformation using a first image obtained using the first spatial frequency data and a second image obtained using the second spatial frequency data; determining a residual spatial phase; correcting, using the transformation, second spatial frequency data and the residual spatial phase, to obtain corrected second spatial frequency data and a corrected residual spatial phase; and generating a magnetic resonance (MR) image using the corrected second spatial frequency data and the corrected residual spatial phase.
Single-shot pseudo-centric epi method for magnetization-prepared imaging
Provided is a method for generating MRI data including applying, by an MRI computing device, an RF excitation pulse, and completing, by the MRI computing device, a K-space by acquiring a plurality of phase encoding line groups, in a state in which any other RF excitation pulse is not applied after applying the RF excitation pulse, in which each of the plurality of phase encoding line groups includes a plurality of phase encoding lines, and an absolute value of an average phase encoding size of a phase encoding line group acquired earlier is not greater than an absolute value of an average phase encoding size of a phase encoding line group acquired later, among the plurality of phase encoding line groups.
CORRECTING THE MAGNETIC FIELD OF A MEDICAL APPARATUS WITH A GANTRY
A method of correcting a magnetic field of a medical apparatus (300) comprising a magnetic resonance imaging system (302). The MRI system includes a magnet (306) for generating the magnetic field within an imaging zone 318. The magnet generates a magnetic field with a zero crossing (346, 404) outside of the imaging zone. The medical apparatus further comprises a gantry (332) configured for rotating a ferromagnetic component (336, 510) about a rotational axis (333). The method comprises the step of installing (100, 200) a magnetic correcting element (348, 900, 1000) located on a radial path (344, 504) perpendicular to the rotational axis. The magnetic correcting element is positioned on the radial path such that change in the magnetic field within the imaging zone due to the ferromagnetic component is reduced. The method further comprises repeatedly: measuring (102, 202, 1204) the magnetic field within the imaging zone; determining (104, 204, 1206) the change in the magnetic field in the imaging zone; and adjusting (106, 206, 1208) the position of the magnetic correcting element along the radial path if the change in the magnetic field is above a predetermined threshold.
Cuttings Analysis For Improved Downhole NMR Characterisation
A method for combining nuclear magnetic resonance (NMR) analysis and digital rock physics (DRP) analysis based on drilling cuttings or other rock samples for improved downhole nuclear magnetic resonance validation and characterisation. A system for performing the method also is provided.
METHOD AND APPARATUS FOR RECONSTRUCTION OF MAGNETIC RESONANCE IMAGES WITH INCOMPLETE SAMPLING
A magnetic resonance (MR) image is created by executing an imaging sequence with an MR apparatus, wherein data in k-space are acquired using multiple receiving antennae, and reconstruction of all image points that correspond to all k-space points belonging to the imaging sequence takes place using a sensitivity profile of the receiving antennae in order to also take account of data at k-space points at positions at which no data were acquired. Data acquired at a number of positions of particular k-space points, the number of the particular k-space points being smaller than the number of all k-space points belonging to the imaging sequence. The aperture of each of the receiving antennae is configured such that, for acquisition of data at a respective k-space point, the spectral main lobe of the respective receiving antenna also extends over k-space points adjacent to the respective k-space point.
MRI METHOD FOR CALCULATING DERIVED VALUES FROM B0 AND B1 MAPS
The invention provides for a magnetic resonance imaging system (100, 300, 100) for acquiring magnetic resonance data (110, 1104) from a subject (118) within an imaging zone (108). The magnetic resonance imaging system comprises a memory (136) for storing machine executable instructions (160, 162, 164, 166, 316) and pulse sequence data (140, 1102). The pulse sequence data comprises instructions for controlling the magnetic resonance imaging system to acquire magnetic resonance data according to a magnetic resonance imaging method. The magnetic resonance imaging system further comprises a processor (130) for controlling the magnetic resonance imaging system. Execution of the machine executable instructions causes the processor to: acquire (1200) the magnetic resonance data by controlling the magnetic resonance imaging system with the pulse sequence data; calculate (1202) a B0 inhomogeneity map (148) by analyzing the magnetic resonance data according to the magnetic resonance imaging method, calculate (1204) a B1 phase map (150) and/or a B1 amplitude map (1106) by analyzing the magnetic resonance data according to the magnetic resonance imaging method; and calculate (1206) a second derivative (1110) of the B1 phase map and/or a second derivative of the B1 magnitude map 1 and/or a second derivative of the B0 in homogeneity map in at least one predetermined direction. The second derivative is calculated using a corrected voxel size in the at least one predetermined direction, wherein the corrected voxel size is calculated using a correction factor calculated from the derivative of the B0 inhomogeneity map.
Method of identifying chronic pain using low frequency fluctuations in nucleus accumbens
A method of identifying chronic pain in a patient including using functional magnetic resonance imaging (fMRI), performing a functional brain scan in the NAc (nucleus accumbens) of a patient brain including extracting activity from the NAc. Database information, which includes fMRI data obtained from healthy patients, may be compared to the extracted activity to determine if patient is a chronic pain patient. In patients with chronic pain, the method may be repeated to evaluate the effects of the treatment. A resting state brain scan may be performed initially, and a Fourier transform may be performed to obtain frequency content. The frequency bands of the method may be broken down to extract information in a 0.01-0.027 Hz frequency band.
REDUCTION OF EDDY CURRENTS DURING FLOW ENCODED MAGNETIC RESONANCE IMAGING
In a method and magnetic resonance (MR) apparatus for establishing imaging sequence parameter values with a reduced eddy current formation for flow-encoded magnetic resonance imaging, a number of different flow-encoded candidate raw datasets are acquired by executing a flow-encoded gradient measurement sequence with different imaging sequence parameter values from a test or calibration region of an examination object. Flow-encoded candidate image datasets are reconstructed from the different flow-encoded candidate raw datasets. A flow-encoded candidate image dataset is selected as a function of a background phase contrast established in a phase-contrast image assigned to the respective flow-encoded candidate image dataset. The imaging sequence parameter values assigned to the flow-encoded candidate image dataset are selected as parameter values for an imaging sequence for subsequent diagnostic flow-encoded magnetic resonance imaging.
Apparatus for generating field-free region, apparatus and method for nano magnetic particle image
Disclosed herein is an apparatus for imaging nano magnetic particles using a 3D array of small magnets. A field-free region generation apparatus includes a hexahedral housing having an opening formed in the first surface thereof such that a measurement head is inserted into a spacing area, a pair of rectangular-shaped magnets installed respectively on two surfaces facing each other, among four surfaces perpendicular to the first surface of the housing, and a pair of magnet arrays installed respectively on the first surface of the housing and on another surface facing the first surface, each of the magnet arrays including multiple small magnets arranged along the edge of the opening.