G01R33/56536

System and method for controlling undesired magnetic field effects in magnetic resonance imaging

A system and method are provided for determining a spatial distribution of susceptibility in a subject using a magnetic resonance imaging (MRI) system. The method includes directing the MRI system to acquire imaging data from an imaging volume within a subject, wherein the imaging volume is subject to both background fields (B.sub.B) originating outside the imaging volume and local fields (B.sub.L) originating from tissue within the imaging volume. The method also includes selecting a size and non-central compute point for an extended Poisson kernel to be applied to the imaging data, subtracting from a delta function to control the background fields (B.sub.B) but not the local fields (B.sub.L), and producing a susceptibility report attributable to the local fields (B.sub.L).

Method and magnetic resonance apparatus for reconstruction of a three-dimensional image data set from data acquired when a noise object distorted the magnetic field in the apparatus
10126400 · 2018-11-13 · ·

In a method for reconstruction of a three-dimensional image data set from magnetic resonance slice data of a target region acquired in target slices while a noise object distorting the magnetic field is present in the target region, for each target slice to be acquired, in addition to a central partition slice corresponding to the respective target slice, location, multiple partition slices adjacent to the central partition slice are acquired in a supplementary encoding direction perpendicular to the slice plane in multiple phase-encoding steps. A correction area and a standard reconstruction area of the target region are determined on the basis of a distortion criterion, obtained by evaluating the slice data that describes the distortion along the supplementary encoding direction. In the standard reconstruction area, only slice data are used, and in the correction area, slice data of partition slices outside the target slice are assigned to target slices in order to correct the distortion.

SYSTEM AND METHOD OF ROBUST QUANTITATIVE SUSCEPTIBILITY MAPPING

Exemplary quantitative susceptibility mapping methods, systems and computer-accessible medium can be provided to generate images of tissue magnetism property from complex magnetic resonance imaging data using the Bayesian inference approach, which minimizes a cost function consisting of a data fidelity term and two regularization terms. The data fidelity term is constructed directly from the complex magnetic resonance imaging data. The first prior is constructed from matching structures or information content in known morphology. The second prior is constructed from a region having an approximately homogenous and known susceptibility value and a characteristic feature on anatomic images. The quantitative susceptibility map can be determined by minimizing the cost function. Thus, according to the exemplary embodiment, system, method and computer-accessible medium can he provided for determining magnetic susceptibility information associated with at least one structure.

Metal resistant MR imaging

A method and apparatus for parallel MR imaging include the steps of: subjecting a portion of a body (10) to a first imaging sequence (21,22) of RF pulses and switched magnetic field gradients, wherein first MR signals (11,12) are acquired via at least two RF coils having different spatial sensitivity profiles within the examination volume, deriving the spatial sensitivity profiles of the at least two RF coils from the acquired first MR signals, subjecting the portion of the body to a second imaging sequence of RF pulses and switched magnetic field gradients, wherein second MR signals are acquired by parallel acquisition via the at least two RF coils with sub-sampling of k-space, andreconstructing a MR image from the acquired second MR signals and from the spatial sensitivity profiles of the at least two RF coils. A type and/or parameters of the first imaging sequence are selected automatically depending on the presence of a metal implant in the body. The selection of the type of the first imaging sequence is made between a gradient echo sequence, if no metal implants are present, and a spin echo sequence or a stimulated echo sequence, if a metal implant is present.

Method for magnetic resonance imaging

The present invention relates to a method for Magnetic Resonance Imaging to depict an object by an image having pixels representing volume element of the object. The method comprises: Immobilizing the object and acquiring a reference image at a first echo time immediately following an excitation, wherein said reference image is complex-valued, with a reference magnitude value and a reference phase value for each pixel; acquiring a target image of the object with said receiver coil at a pre-selected second echo time, wherein said target image is complex-valued, with a target magnitude value and a target phase value for each pixel; subtracting, pixel by pixel, the reference phase value from the target phase value to obtain a corrected phase value for each pixel; and obtaining said image from said target magnitude values and said corrected phase values.

METHOD AND MAGNETIC RESONANCE APPARATUS AUTOMATICALLY FILLING A MEASURING QUEUE WITH VARYING IMAGING PARAMETERS
20180306878 · 2018-10-25 · ·

In a method for performing MR measurements in an MR system on an object, MR signals of the object are acquired using an imaging sequence with a first set of imaging parameters. An amended copy of the imaging sequence is automatically created with a second set of imaging parameters, which has all the imaging parameters used in the first set, wherein the second set has at least one imaging parameter modified with respect to the first set that differs from the corresponding imaging parameter of the first set according to a defined amendment. The remaining imaging parameters of the second set correspond to the imaging parameters of the first set. The amended copy is automatically configured in a measurement queue in which all the imaging sequences are stored that are to be carried out in the future on the examination object are stored.

Robust principal component analysis for separation of on and off-resonance in 3D multispectral MRI

Accelerated 3D multispectral imaging (MSI) on a magnetic resonance imaging (MRI) system uses phase-encoding in two dimensions and frequency-encoding in the third. The method generates randomized k-space undersampling patterns that vary between different spectral bins to determine k-space samples to be acquired in each spectral bin; orders k-space samples into echo trains that determine gradient waveforms; initializes the gradient waveforms, RF waveforms, and timing information; plays the gradient and RF waveforms using the timing information to excite and refocus different spatial and spectral bin regions; acquires undersampled MRI signal data on the MRI system from the spatial and spectral bin regions; uses robust principal component analysis to reconstruct on-resonance images and off-resonance images represented as sets of low rank and sparse matrices from the undersampled MRI signal data; combines the on-resonance images and off-resonance images to yield a final image; and presents the final image on a display.

Magnetic resonance imaging apparatus

A magnetic resonance imaging apparatus includes an acquisition unit which acquires first data in which a tissue of interest has higher signal intensity than a background and second data in which the tissue of interest has lower signal intensity than the background, with regard to images of the same region of the same subject, and a generation unit which generates, on the basis of the first data and the second data, third data in which the contrast of the tissue of interest to the background is higher than those in the first and second data.

SYSTEM AND METHOD FOR CORRECTING ONE OR MORE ARTIFACTS WITHIN A MULTI-SPECTRAL MAGNETIC RESONANCE IMAGE

A method for correcting one or more artifacts within a multi-spectral magnetic resonance image is provided. The method includes acquiring a plurality of spectral bins each including a plurality of voxels and corresponding to a different frequency of MR signals emitted by an imaged object. The plurality of voxels of each spectral bin correspond to the frequency of the spectral bin so as to define a spatial coverage of the spectral bin. The method further includes expanding each spectral bin by increasing the spatial coverage of the spectral bin, and generating the multi-spectral magnetic resonance image based at least in part on the expanded spectral bins.

SYSTEMS AND METHODS FOR CALIBRATED MULTI-SPECTRAL MAGNETIC RESONANCE IMAGING
20180292491 · 2018-10-11 ·

Systems and methods are provided for performing a calibration pre-scan prior to acquiring data using a magnetic resonance imaging (MRI) system performing a multi-spectral imaging (MSI) acquisition. Information from the calibration scan is used to optimize the scanning and data collection during the MSI scan. As a result, scan times and motion artifacts are reduced. In addition, image resolution can also be increased, thereby improving image quality. As one example, the MSI acquisition can be a MAV-RIC acquisition. In general, the calibration data is used to determine the minimum number of spectral bins required to achieve acceptable image quality near a specific metallic implant or device.