An apparatus for detecting and repairing a ring artifact in a multi-spectral magnetic resonance image includes an image processor, which is configured to obtain an off-resonance magnetic field map and a deblurred composite image, to calculate a spatial gradient of the image based on the magnetic field map, to kernel search the spatial gradient, to mask the image, based on the kernel search, in order to identify voxels affected by a ring artifact, and to apply a filter in order to smooth intensities of the voxels identified by the image mask.

A technology of improving image quality of a calculation image or parameter estimation accuracy even in a case where a method of simultaneously generating calculation images of a plurality of parameters is used is provided. Thus, by utilization of a reconstructed image in an optimal resolution of each parameter to be estimated, a value of the parameter is estimated and a calculation image that is a distribution of the value of the parameter is acquired. A reconstructed image in an optimal resolution is acquired by adjustment of a resolution of a reconstructed image acquired in an optimal resolution of an estimation parameter with the highest optimal resolution among parameters to be estimated in scanning. Alternatively, in scanning, only a reconstructed image used for calculation of a predetermined parameter to be estimated is acquired in an optimal resolution of the parameter to be estimated.

A susceptometer includes: a substrate; a plurality of electrodes including: a first pair of electrodes disposed on the substrate; a second pair of electrodes disposed on the substrate, the second pair of electrodes arranged collinear with the first pair of electrodes to form a set of aligned electrodes; and a third pair of electrodes disposed on the substrate, the third pair of electrodes arranged noncollinearly with set of aligned electrodes; and a solenoid circumscribingly disposed around the electrodes to: receive the sample such that the solenoid is circumscribingly disposed around the sample; receive an alternating current and produce an primary magnetic field based on the alternating current; and subject the sample to the primary magnetic field.

Disclosed is a magnetic resonance imaging apparatus that calculates a susceptibility map using a weighting image that reflects a phase variation with high accuracy. The weighting image is calculated from a phase image obtained from a complex image obtained by MRI. First, a region used in calculation of the phase variation is set as a calculation region, and then, a standard deviation or a variance of pixel values of the phase image in the calculation region is set as the phase variation. Further, the phase variation is converted into a weight that monotonically decreases in a broad sense as the phase variation increases to obtain the weighting image.

An apparatus and method are provided for performing phase unwrapping for an acquired magnetic resonance (MR) image. The method includes modelling the MR phase in the MR image using a Markov random field (MRF) in which the true phase (t) and the wrapped phase (w) are modelled as random variables such that at voxel i of said MR image (t)(i)=(w)(i)+2n(i), where n(i) is an unknown integer that needs to be estimated for each voxel i. The method further includes constructing a graph consisting of a set of vertices V and edges E and two special terminal vertices representing a source s and sink t, where there is a one-to-one correspondence between cuts on the graph and configurations of the MRF, a cut representing a partition of the vertices V into disjoint sets S and T such that sS and tT. The method further includes finding the minimum energy configuration, E(n(i)|(w)) of the MRF on the basis that the total cost of a given cut represents the energy of the corresponding MRF configuration, where the cost of a cut is the sum of all edges going from S to T across the cut boundary. The method further includes using the values of n(i) in the minimum energy configuration to perform the phase unwrapping from (w) to (t) for the MR image. A confidence may be computed for each voxel using dynamic graph cuts. The unwrapped phase from two MR images acquired at different times may be used to estimate a field map from the phase difference between the two MR images. The field map may be converted into a deformation field which is then used to initialize a non-rigid image registration of the acquired MR image against a reference image. The deformation field of the non-rigid registration is controlled to be smoother where the confidence is high.

A material for a magnetic resonance installation is provided, wherein the material includes a support material and a magnetic doping material which is admixed in a specific proportion. The doping material exhibits an anisotropic susceptibility. In respect of the anisotropic susceptibility, the doping material exhibits a mean orientation along a predefined direction. An essentially homogeneous intermixture of the support material and the doping material is present within a volume of the material which is smaller than 1 mm.sup.3.

A system and method for generating MR phase contrast images near metal include an MRI apparatus that includes an MRI system having a plurality of gradient coils and an RF transceiver system and an RF switch controlled by a pulse module to transmit RF signals to an RF coil assembly. The MRI apparatus also includes a computer programmed to acquire a plurality of three-dimensional (3D) MR data sets and to generate a plurality of frequency images based on the plurality of 3D MR data sets. Each 3D MR data set is acquired using a central transmit frequency and a central receive frequency set to an offset frequency value that is distinct for each 3D MR data set. The computer is also programmed to convert the plurality of frequency images to a plurality of time domain images and to generate a phase image based on the plurality of time domain images.

An MRI system acquires a susceptibility-weighted image by acquiring a first RF echo signal in a first echo time for providing an image exclusive of susceptibility-weighting and acquiring a second RF echo signal in a second echo time longer than the first echo time for providing an image including susceptibility-weighting. A compensation gradient field is applied for compensating for field inhomogeneity and in response, a third RF echo signal is acquired in a third echo time longer than the second echo time. First, second and third images are generated in response to data derived from the first, second and third RF echo signals respectively and data of the first, second and third images is combined to provide image data representing an image compensating for magnetic resonance signal attenuation in the second image.

An example implementation of a method for mapping tissue magnetic susceptibility includes acquiring magnetic resonance (MR) images acquired at multiple echo times, where the MR images correspond to a subject comprising at least two species of protons, and where each species has a different chemical shift in its respective resonance frequency. The method also includes determining, for each species, an estimated chemical shift value, determining an estimated map of magnetic field inhomogeneity based on the estimated chemical shift values, determining an estimated susceptibility distribution of the subject and an error of each estimated chemical shift value based on the estimated map of magnetic field inhomogeneity and prior information regarding the subject, and generating an image of the subject based on the estimated susceptibility distribution.

A material for use in a magnetic resonance system includes a carrier material and a doping material. The carrier material and the doping material are admixed in a specific proportion. A volume of the material smaller than 1 mm.sup.2 contains a substantially homogeneous intermixing of the carrier material and the doping material.