Patent application number | Description | Published |
20090128148 | NMR tomography method based on NBSEM with 2D spatial encoding by two mutually rotated multipole gradient fields - A nuclear magnetic resonance (NMR) imaging method | 05-21-2009 |
20090302838 | MR method for selective excitation - A magnetic resonance method for using radio frequency pulses for spatially selective and frequency selective or multidimensionally spatially selective excitation of an ensemble of nuclear spins with an initial distribution of magnetization in a main magnetic field aligned along a z-axis, wherein a spin magnetization with a given target distribution of magnetization is generated, and for refocusing the spin magnetization, is characterized in that the radio frequency pulse is used as a sequence of sub-pulses of independent duration, courses of gradients and spatial and/or spectral resolution, comprising one or more large angle RF pulses with tip angles greater than or approximately equal to 15°, which generate a gross distribution of magnetization approximating the target distribution of magnetization or a desired modification of the distribution of magnetization with a mean deviation less than or approximately equal to 15°, wherein the actual effect of the LAPs on the distribution of spin magnetization before the radio frequency pulse is used is calculated by integration of the Bloch equations without small angle approximation, and one or more small angle RF pulses=SAPs with tip angles less than or approximately equal to 15° reducing the difference between the target distribution of magnetization and the gross distribution of magnetization caused by the LAPs. | 12-10-2009 |
20100102819 | Sense Shimming (SSH): a fast approach for determining B0 field inhomogeneities using sensitivity encoding - The pursuit for ever higher field strengths and faster data acquisitions has led to the construction of coil arrays with high numbers of elements. With the SENSE technique it has been shown, how the sensitivity of those elements can be used for spatial image encoding. A method in accordance with the present invention, largely abstains from using encoding gradients. The resulting sensitivity encoded free induction decay (FID) data is then not used for imaging, but for determining field inhomogeneity distribution. The method has therefore been termed SSH for Sense SHimming. | 04-29-2010 |
20110080169 | Method for position dependent change in the magnetization in an object in a magnetic resonance experiment - A method for position dependent change in the magnetization in an object, according to a requirement in a magnetic resonance measurement, wherein radio-frequency pulses are irradiated in conjunction with supplementary magnetic fields that vary in space and over time and are superposed on the static and homogeneous basic field of a magnetic resonance measurement apparatus along a z-direction, is characterized in that non-linear supplementary magnetic fields are used, whose spatial gradient of the z-component is not constant at least at one instant of the irradiation, and that the radio-frequency pulses to be irradiated are calculated in advance, wherein progressions over time of the field strengths of the supplementary magnetic fields in the region of the object that are calculated and/or measured position-dependently are included in this calculation. This enables change in the magnetization with an at least locally spatially higher resolution and/or shorter irradiation duration of the RF pulses and supplementary magnetic fields than is feasible with linear supplementary magnetic fields produced by conventional gradient systems. In particular, this is possible under the technical and physiological conditions that currently constrain the performance of the known methods using linear supplementary fields. | 04-07-2011 |
20110148410 | Method for data acquisition acceleration in magnetic resonance imaging (MRI) using receiver coil arrays and non-linear phase distributions - A method for accelerating data acquisition in MRI with N-dimensional spatial encoding has a first method step in which a transverse magnetization within an imaged object volume is prepared having a non-linear phase distribution. Primary spatial encoding is thereby effected through application of switched magnetic fields. Two or more RF receivers are used to simultaneously record MR signals originating from the imaged object volume, wherein, for each RF receiver, an N-dimensional data matrix is recorded which is undersampled by a factor R | 06-23-2011 |
20110241678 | Method for homogenizing resolution in magnet resonance tomography measurements using non-linear encoding fields - A method for magnetic resonance (=MR) imaging, wherein non-linear gradient fields are applied for the purpose of spatial encoding to acquire images of an object to be imaged and wherein the magnet resonance signal radiated from the object to be imaged is sampled on grids in time, to thereby obtain sampling points, is characterized in that the object to be imaged is mapped completely in regions of stronger gradient fields by increasing the density of the sampling points in the center of k-space, and additional sampling points are specifically acquired in the outer regions of k-space according to a k-space sampling pattern depending on the desired distribution of the resolution in the measurement, wherein the MR measurement is calculated with the additional sampling points. An MR imaging method is thereby provided by means of which homogenized resolution is achieved in the MR measurements using non-linear gradient fields for spatial encoding. | 10-06-2011 |
20120025822 | Method of MR (=magnetic resonance) with spatial encoding to generate an image of spectroscopic data - A method of MR with spatial encoding to generate an image or spectroscopic data of an object of investigation inside an MR apparatus comprises the steps of (a) selecting a volume of interest within the object of investigation, (b) applying an RF pulse to generate a transverse magnetization within the object of investigation, (c) preparing a nonlinear phase distribution within the object of investigation by application of spatially encoding magnetic fields (SEMs), the SEMs comprising of a nonlinear gradient field or a combination of linear and nonlinear gradient fields, (d) effecting primary spatial encoding through application of SEMs, and (e) recording MR signals originating from the object of investigation. Step (c) or (d) thereby comprises applying a sequence of at least two SEMs, at least one of which contains a nonlinear field gradient and at least two of the SEMs having different field geometries. The sequence of SEMs is applied at a point in time from and including the excitation of the object of interest in step (b) up to and including the recording of the MR signals in step (e), to thereby introduce a temporal shift of the signals arising from spatially different locations within the selected volume of interest, that is to thereby introduce a shift of local spatial frequency components. A sampling window for recording of the respective MR signals is set and signals originating from the volume of interest are recorded in step (e) and undesired signals originating from outside the volume of interest are suppressed. | 02-02-2012 |
20120249137 | Method of dynamically compensating for magnetic field heterogeneity in magnetic resonance imaging - A method to compensate for the magnetic field heterogeneity inside an object of investigation in a MR device obtains an uncorrected magnetic field distribution of the object and executes an MR sequence with a desired k-space coverage by applying RF pulses to generate a transverse magnetization within the object. MR signal data is recorded, magnetic field shimming parameters are dynamically updated and MR signal data are reconstructed to produce images or localized spectroscopic data. Artifacts in a reconstructed image resulting from an uncorrected magnetic field distribution are suppressed by temporally separating MR signals originating from at least two different sub-volumes within a volume of transverse magnetization by generating a nonlinear phase distribution within the object and by dynamically updating shimming parameters to compensate for the field inhomogeneity distributions within the different sub-volumes in the volume of transverse magnetization. | 10-04-2012 |
20120262171 | Method of magnetic resonance imaging for the selection and recording of curved slices - A method of MR imaging applies a magnetic field B | 10-18-2012 |
20120268124 | Method for quasi-continous dynamic motion correciton in magnetic resonance measurements - A method of MR imaging and spectroscopy reduces artifacts occurring due to the motion of an object to be represented, wherein the object position is determined quasi-continuously during the runtime of the MR acquisition, which includes one or more partial acquisitions (TA), and wherein motion correction is performed, which comprises dynamic adaptation of the frequency and phase settings of the RF system of the tomograph and of the orientation and amplitudes of the gradients during the runtime of the MR acquisition according to the current object position. The motion correction is thereby applied during a signal weighting period, during a signal read-out period, or between and/or during the two stated periods and the adaptations for motion correction are performed without interrupting or slowing the temporal progression of the MR acquisition. In this way, artifacts due to motion of the object to be represented can be further reduced. | 10-25-2012 |
20130102879 | Method For Correcting Susceptibility-Induced Image Artifacts In MRI After Prospective Motion Correction - A method of magnetic resonance imaging (MRI) is characterized by the following steps: a) forming a susceptibility model ( | 04-25-2013 |
20140035576 | Method and apparatus for accelerating magnetic resonance imaging - A method of MRI entails recording and storing MR signals from an object to produce an old set of data. A further measurement of the object is then initiated at a later time to record new MR data, whereby k-space is undersampled in the further measurement. The old data are corrected for changes in the new position of the object, for changes in the sensitivity and exact spatial positioning of the receiver coils as well as for changes in the actual field shimming. The old and new data are then combined to create a new, high resolution image of the object. | 02-06-2014 |
20140125335 | Method for magnetic resonance imaging - A method of MRI for reduction of motion artifacts in 3D MR data acquisition with multiple segments comprises: the complete acquisition being divided into two parts: basic acquisition and complementary acquisition. Basic acquisition is performed at the beginning. Complementary acquisition is performed after the basic acquisition is finished. View Reordering is prepared for basic acquisition and complementary acquisition separately. Motion monitoring is performed regularly during the data acquisition. Whenever motion is detected, data acquisition stops. Image reconstruction is performed when motion occurs in the phase of complementary acquisition. The final reconstructed image is free of motion artifacts. | 05-08-2014 |