A guide map is created for use in placing a spectroscopic single voxel in a region of interest in single voxel magnetic resonance spectroscopy. An anatomical planning image of the region of interest is obtained through MRI. A spectroscopy voxel is stepped across the region of interest, characteristics of the magnetic field used in the MRI are measured at each location of the imaging voxel, and a guide-FWHM map indicative of the homogeneity/inhomogeneity of the magnetic field over the region of interest is derived using the measurements. The guide map is created by overlaying the guide-FWHM map on the anatomical planning image. A spectroscopic single voxel of a size corresponding to that of the spectroscopy voxel is placed within the region of interest as per the guide map. Then spectral data is acquired from the region of interest confined to the single voxel.

A method for generating a magnetic resonance image of an object in a magnetic resonance imaging (MRI) system, wherein the object contains at least one metallic implant is provided. The MRI system provides multiple excitations of at least part of the object. The MRI system reads out image signals from the object. The MRI system saves the readout image signals as image data. A field-map is generated from the image data using a goodness-of-fit process which uses a goodness-of-fit metric, matched-filter, and/or similar fitting techniques to fit expected signals from each excitation to the image data.

A dynamic field camera arrangement for monitoring electromagnetic field behavior in a spatial region comprises a main magnetic field and a radiofrequency (RF) field limited to a first RF band, particularly in an MRI or NMR apparatus. The arrangement comprises a magnetic field detector set comprising a plurality of low-frequency magnetic field detectors, each one of said magnetic field detectors comprising a magnetic resonance (MR) active substance, means for pulsed MR excitation of said substance and means for receiving an MR signal generated by said substance, wherein said pulsed excitation and said MR detector signal is in a second RF band that does not overlap said first RF band. The MR signal receiving means comprise a first RF filter which suppresses RF signal from said first RF band and transmits RF signal from said second RF band.

Phase variations of the transverse magnetization in magnetic resonance induced by superimposed physical phenomenae or by intrinsic deviations of the main magnetic B0 field are separated from Feature Space set by demodulation and deconvolution, either by electrical circuits or by equivalent computational methods, permitting mapping and measurement of these induced phase variations independent of Feature Space.

A method for establishing a magnetic resonance system actuation sequence is described. A first number of field distribution maps are acquired for slices of the measurement region, and a radiofrequency pulse train is established on the basis thereof for the magnetic resonance system actuation sequence. This acquisition of the first number of field distribution maps may be brought about on the basis of an acquisition scheme. A reduced number of field distribution representation maps are established on the basis of the acquired field distribution maps, which field distribution representation maps represent the first number of acquired field distribution maps in accordance with a predetermined optimization criterion, and the radiofrequency pulse train is established on the basis of the field distribution representation maps.

In a method and magnetic resonance apparatus for determining a shim setting in order to increase a homogeneity of the basic magnetic field of the scanner of the apparatus by operating a shim element, information is obtained concerning the dependence of an induced field of the shim element on a set shim setting. A first field map is recorded and a first shim setting for the shim element is determined based on the first field map. A second field map is recorded while the shim element is driven with the first shim setting. A field induced by the shim element by the first shim setting is determined based on the first field map and the second field map. A second shim setting for the shim element is determined based on the determined induced field and the acquired information.

A method and a system for measuring and calibrating an imaging magnetic field in a magnetic resonance apparatus are provided. The method includes: providing the imaging magnetic field, where the imaging magnetic field is adapted for scanning an object; sampling a signal corresponding to the imaging magnetic field; processing the signal to obtain an actual magnetic field intensity; and calibrating based on a difference between the actual magnetic field intensity and a target magnetic field intensity. The system includes: a magnetic component, adapted for scanning an object to be imaged; a sampling unit, adapted for sampling a signal corresponding to the imaging magnetic field; a processing unit, adapted for processing the signal to obtain an actual magnetic field intensity; a calibration unit, adapted for calibrating based on a difference between the actual magnetic field intensity and a target magnetic field intensity; and a control unit, adapted for controlling the system.

In a method and test apparatus for determining a deviation in the homogeneity of a basic magnetic field of a magnetic resonance scanner, test vessels are positioned in a test plane that first and second positions along a direction in the scanner, and measurement data are acquired with the test vessels at said respective positions. The acquired measurement data are provided to a processor, wherein a deviation of the homogeneity of the basic magnetic field is determined based thereon.

According to some aspects, a method of producing a permanent magnet shim configured to improve a profile of a B.sub.0 magnetic field produced by a B.sub.0 magnet is provided. The method comprises determining deviation of the B.sub.0 magnetic field from a desired B.sub.0 magnetic field, determining a magnetic pattern that, when applied to magnetic material, produces a corrective magnetic field that corrects for at least some of the determined deviation, and applying the magnetic pattern to the magnetic material to produce the permanent magnet shim. According to some aspects, a permanent magnet shim for improving a profile of a B.sub.0 magnetic field produced by a B.sub.0 magnet is provided. The permanent magnet shim comprises magnetic material having a predetermined magnetic pattern applied thereto that produces a corrective magnetic field to improve the profile of the B.sub.0 magnetic field.

A method for determining a position of a mobile device relative to a B0 field magnet along a z-coordinate axis, and a device and a magnetic resonance tomography unit for performing the method are provided. The device includes a magnetic field strength sensor arranged in a fixed relative position. A characteristic magnetic field strength B.sub.ref of the B0 field magnet that emerges for a plurality of x-y coordinate pairs with a same reference z-coordinate z.sub.ref is ascertained. The device is moved along the z-coordinate axis until the magnetic field strength sensor measures the characteristic magnetic field strength B.sub.ref.