A method for estimating a magnetic field deviation, a magnetic resonance device, and a computer program product are disclosed. In accordance with the method, at least one gradient value is provided, wherein each gradient value describes a gradient strength of the respective gradient magnetic field, e.g., the setpoint gradient magnetic field. The magnetic resonance device generates a main magnetic field in a main magnetic field direction. The at least one value of a deviation is estimated by applying the at least one gradient value to a magnetic field model. In this case, in accordance with a magnetic field model, a deviation of the gradient magnetic field from a setpoint gradient magnetic field is described by at least one vectorial component in a spatial direction deviating from the main magnetic field direction.

A MRI device including a main field unit for establishing a main magnetic field (MF) in an imaging region, a gradient coil assembly for generating a gradient field in the imaging region, a RF arrangement for sending excitation signals to and receiving MR signals from the imaging region, a field camera for determining MF information in the imaging region, the field camera comprising multiple MF sensors arranged at measurement positions enclosing the imaging region, and a controller. The controller is configured to receive sensor data for each measurement positions, from the sensor data, calculate the MF information for the imaging region, and implement a calibration and/or correction measure depending on the MF information. The field camera may be a vector-field camera acquiring vector-valued sensor data describing the MF at each measurement positions three-dimensionally. The controller may determine the MF information to three dimensionally describe the MF in the imaging region.

A dielectric pad and method of fabricating a dielectric pad for improving signal-to-noise ratio and image quality in MRI procedures. The dielectric pad includes a composition of TiO.sub.2, BaTiO.sub.3, or SiC mixed with a solvent to produce a flexible and stretchable pad for MRI use. The flexible and stretchable pad is configured to conform to various body shapes, to be wrap-able, and to be wearable for MR imaging procedures.

A dielectric pad and method of fabricating a dielectric pad for improving signal-to-noise ratio and image quality in MRI procedures. The dielectric pad includes a composition of TiO.sub.2, BaTiO.sub.3, or SiC mixed with a solvent to produce a flexible and stretchable pad for MRI use. The flexible and stretchable pad is configured to conform to various body shapes, to be wrap-able, and to be wearable for MR imaging procedures.

A MRI device including a main field unit for establishing a main magnetic field (MF) in an imaging region, a gradient coil assembly for generating a gradient field in the imaging region, a RF arrangement for sending excitation signals to and receiving MR signals from the imaging region, a field camera for determining MF information in the imaging region, the field camera comprising multiple MF sensors arranged at measurement positions enclosing the imaging region, and a controller. The controller is configured to receive sensor data for each measurement positions, from the sensor data, calculate the MF information for the imaging region, and implement a calibration and/or correction measure depending on the MF information. The field camera may be a vector-field camera acquiring vector-valued sensor data describing the MF at each measurement positions three-dimensionally. The controller may determine the MF information to three dimensionally describe the MF in the imaging region.

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 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 bridge member containing MR responsive material is provided in an open space between body parts to establish a correspondence between the body parts. The MR responsive material generates magnetic resonance signals in response the RF excitation, so that between the separate body parts via the bridge member magnetic resonance signal are obtained from positions between which there is at most a limited spatial variation of the main magnetic field, so that phase ambiguities between the signals from these positions are avoided. Thus, chemical shift separation, notably water-fat separation though a region-of-interest containing several (both) body parts may rely on a smoothness condition imposed on the spatial distribution of the main magnetic field. This avoids artefacts, such as water-fat swaps when separating water and fat contributions in the reconstructed magnetic resonance image.

A magnet arrangement having a hollow-cylindrical magnet element that has an axial length L.sub.z,M and an inner radius R.sub.in, is constructed from magnet segments arranged concentrically around the z-axis, and has a Halbach magnetization. At least one ring-shaped magnet element has a notched, hollow-cylindrical cutout extending circumferentially around the z-axis symmetrically with respect to the plane z=0, the axial extent L.sub.z,A of the cutout being less than the axial length L.sub.z,M of the magnet element. The cutout has a radial depth T.sub.A and an axial length L.sub.z,A<L.sub.z,M between the z-positions z=−z.sub.A to z=+z.sub.A. The radial depth T.sub.A and the axial length L.sub.z,A of the cutout are to ensure that the remaining inhomogeneity of the homogenous magnetic field B.sub.0 in a predefined measurement volume having an axial plateau length L.sub.P in the center of the magnet arrangement does not exceed 10 ppm.

A magnet arrangement having a hollow-cylindrical magnet element that has an axial length L.sub.z,M and an inner radius R.sub.in, is constructed from magnet segments arranged concentrically around the z-axis, and has a Halbach magnetization. At least one ring-shaped magnet element has a notched, hollow-cylindrical cutout extending circumferentially around the z-axis symmetrically with respect to the plane z=0, the axial extent L.sub.z,A of the cutout being less than the axial length L.sub.z,M of the magnet element. The cutout has a radial depth T.sub.A and an axial length L.sub.z,A<L.sub.z,M between the z-positions z=−z.sub.A to z=+z.sub.A. The radial depth T.sub.A and the axial length L.sub.z,A of the cutout are to ensure that the remaining inhomogeneity of the homogenous magnetic field B.sub.0 in a predefined measurement volume having an axial plateau length L.sub.P in the center of the magnet arrangement does not exceed 10 ppm.