Abstract: A magnetic resonance (MR) apparatus comprises magnet means for generating a main magnetic field in a sample region, encoding means for generating encoding magnetic fields superimposed to the main magnetic field, RF transmitter means for generating MR radiofrequency fields, driver means for operating said encoding means and RF transmitter means to generate superimposed time dependent encoding fields and radiofrequency fields according to an MR sequence for forming images or spectra; and acquisition means for acquiring an MR signal from said object. The magnet means comprise a primary magnetic field source providing a static magnetic field B0 and at least one secondary magnetic field source providing an adjustable magnetic field B?.

Abstract: A magnetic resonance (MR) apparatus comprises magnet means for generating a main magnetic field in a sample region, encoding means for generating encoding magnetic fields superimposed to the main magnetic field, RF transmitter means for generating MR radiofrequency fields, driver means for operating said encoding means and RF transmitter means to generate superimposed time dependent encoding fields and radiofrequency fields according to an MR sequence for forming images or spectra; and acquisition means for acquiring an MR signal from said object. The magnet means comprise a primary magnetic field source providing a static magnetic field B0 and at least one secondary magnetic field source providing an adjustable magnetic field B?.

Abstract: A magnetic resonance imaging system includes a gradient system and a processor for controlling the magnetic resonance imaging system.

Abstract: The invention relates to a magnetic resonance imaging system (100). The magnetic resonance imaging system (100) comprises a gradient system and a processor (124) for controlling the magnetic resonance imaging system (100). Execution of machine executable instructions causes the magnetic resonance imaging system (100) to: acquire by coil elements (114) first magnetic resonance data simultaneously from a group of passive local probes 5 (302, 312, 402, 702, 901), wherein the first group of passive local probes (302, 312, 402, 702, 901) comprises a plurality of passive local probes (302, 312, 402, 702, 901) located spaced apart from each other; disentangle contributions to the first magnetic resonance data from the individual local probes, calculate for the magnetic resonance imaging system (100) a gradient impulse response function of the gradient system using the first magnetic resonance data 10 from the local probes; determine correction factors using the gradient impulse response function.

Abstract: A magnetic resonance (MR) apparatus comprises magnet means for generating a main magnetic field in a sample region, encoding means for generating encoding magnetic fields superimposed to the main magnetic field, RF transmitter means for generating MR radiofrequency fields, driver means for operating said encoding means and RF transmitter means to generate superimposed time dependent encoding fields and radiofrequency fields according to an MR sequence for forming images or spectra; and acquisition means for acquiring an MR signal from said object. The magnet means comprise a primary magnetic field source providing a static magnetic field B0 and at least one secondary magnetic field source providing an adjustable magnetic field B?.

Abstract: 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.

Abstract: A method of determining the position of at least one magnetic field probe located within a pre-defined volume of interest within a magnetic resonance (MR) imaging or spectroscopy arrangement comprises applying a spatially and temporally variable magnetic reference field having a unique time-course at every point in said volume of interest during a preselected time window. An MR signal is acquired from said magnetic field probe during said time window, and the position of the probe is determined from the probe MR signal.

Abstract: A method for acquiring an image or spectrum of a subject or object residing within the magnetic field of a magnetic resonance apparatus, comprises the steps of: executing a predetermined pulse sequence for applying gradient magnetic fields and for coupling in electromagnetic excitation pulses to induce nuclear magnetic resonance within the subject or object; detecting an electromagnetic signal resulting from said magnetic resonance; and constructing at least one image or magnetic resonance spectrum of said subject or object from said detected electromagnetic signal. According to the invention, said coupling in of the electromagnetic excitation pulse and/or said detecting of the electromagnetic signal are carried out substantially by means of travelling electromagnetic waves.

Abstract: A method for acquiring an image or spectrum of a subject or object residing within the magnetic field of a magnetic resonance apparatus, comprises the steps of: executing a predetermined pulse sequence for applying gradient magnetic fields and for coupling in electromagnetic excitation pulses to induce nuclear magnetic resonance within the subject or object; detecting an electromagnetic signal resulting from said magnetic resonance; and constructing at least one image or magnetic resonance spectrum of said subject or object from said detected electromagnetic signal. According to the invention, said coupling in of the electromagnetic excitation pulse and/or said detecting of the electromagnetic signal are carried out substantially by means of travelling electromagnetic waves.

Abstract: A method of processing magnetic resonance imaging signals from a plurality of receiver coils of a magnetic resonance imaging system, comprises the steps of receiving from said plurality of receiver coils a corresponding plurality of original signals in the time-domain forming an n-dimensional signal vector ?k wherein n is the number of receiver coils; linearly combining said original signals so as to obtain a plurality of transformed signals forming an m-dimensional transformed signal vector ??k wherein m is smaller than n and wherein said step of linearly combining is represented by a linear transformation matrix A; and reconstructing an image from said plurality of transformed signals.

Abstract: A magnetic field probe comprises a sample (4) that exhibits magnetic resonance at an operating frequency, an electrically conductive structure (8) surrounding the sample for receiving a magnetic resonance signal therefrom, and a solid jacket (12) encasing the sample and the conductive structure. The jacket is made of a hardened two-component epoxy system containing a paramagnetic dopant dissolved therein, with the concentration of the dopant being chosen such that the jacket has a magnetic susceptibility that is substantially identical to the magnetic susceptibility of the conductive structure.

Abstract: A novel magnetic resonance imaging method is described, wherein undersampled magnetic resonance signals are acquired by a receiver antenna system having spatial sensitivity profiles and the image being reconstructed from the undersampled magnetic resonance signals and the spatial sensitivity profiles. The reconstruction of the image is provided by an optimization of a cost function which accounts for any of noise statistics, signal statistics, and the spatial response function, the latter of which is defined by the spatial signal response from the object to be imaged, separately for each individual pixel.

Abstract: This invention describes the combination of SSFP, a method for accelerating data acquisition, and an eddy current compensation method. This synergistic combination allows acquisition of images with high signal-to-noise ratio, high image contrast, high spatial and temporal resolutions, and good immunity against system instabilities. k-t BLAST and k-t SENSE are the preferred method for accelerating data acquisition, since they allow high acceleration factors, but other methods such as parallel imaging and reduced field-of-view imaging are also applicable. Typical applications of this invention include cine 3D cardiac imaging, and 2D real-time cardiac imaging.

Abstract: This invention describes the combination of SSFP, a method for accelerating data acquisition, and an eddy current compensation method. This synergistic combination allows acquisition of images with high signal-to-noise ratio, high image contrast, high spatial and temporal resolutions, and good immunity against system instabilities. k-t BLAST and k-t SENSE are the preferred method for accelerating data acquisition, since they allow high acceleration factors, but other methods such as parallel imaging and reduced field-of-view imaging are also applicable. Typical applications of this invention include cine 3D cardiac imaging, and 2D real-time cardiac imaging.

Abstract: A novel magnetic resonance imaging method is described, wherein undersampled magnetic resonance signals are acquired by a receiver antenna system having spatial sensitivity profiles and the image being reconstructed from the undersampled magnetic resonance signals and the spatial sensitivity profiles. The reconstruction of the image is provided by an optimization of a cost function which accounts for any of noise statistics, signal statistics, and the spatial response function, the latter of which is defined by the spatial signal response from the object to be imaged, separately for each individual pixel.

Abstract: A novel magnetic resonance (MR) imaging or spectroscopy method is presented, in which a main magnetic field is generated in an object by a main magnet and superimposed magnetic fields and adiofrequency fields are generated according to an MR sequence for forming images or spectra. Object signals are acquired from the object with at least one object detector during execution of the MR sequence. Further, additional data are acquired from at least one monitoring field probe positioned in the vicinity of and surrounding the object, during execution of the MR sequence. The additional data from the monitoring field probes are used for adjusting the MR sequence such as to correct for imperfections in the field response of the object detectors, and the additional data from the monitoring field probes are used in conjunction with the object signals for reconstruction of the images or spectra.

Abstract: In a magnetic resonance imaging method an echo train is generated of successive magnetic resonance signals from an object to be examined.

Abstract: In a magnetic resonance imaging system the receiver antennae system includes receiver coils which are electromagnetically coupled with a relative coupling degree in the range (?, 0.5), preferably in the range (?, 0.2).

Abstract: In SENSitivity Encoding (SENSE), the reconstructed images are susceptible to amplified noise and/or artifacts if the underlying matrix inversion procedure is ill-conditioned. In this work, we propose to firstly apply the conventional SENSE algorithm to obtain an initial estimate. This initial estimate undergoes filtering to improve the signal-to-noise ratio. Then, it is fed back to the reconstruction as a reference image to estimate the amount of aliasing that may arise from regularization. We derive the optimal regularized solution that minimizes the weighted sum of artifact and noise power.

Abstract: Successive magnetic resonance images are reconstructed from the respective sets of magnetic resonance signals of the dynamic series on the basis of the identified distribution of likelihood of changes and optionally the static reference image. The magnetic resonance signals are acquired by way of a receiver antennae system having a spatial sensitivity profile and in an undersampled fashion and the successive magnetic resonance images are reconstructed optionally also on the basis of the spatial sensitivity profile.