Siemens Aktiengesellschaft

Siemens Healthcare Gmbh

Siemens Medical Solutions Usa, Inc.

University of Virginia

Siemens Healthineers Ag

Alto Stemmer

Berthold Kiefer

Thorsten Feiweier

Cong Zhao

Marcel Dominik Nickel

Craig H Meyer

Matthias Fenchel

Josef Pfeuffer

Michael Deimling

Daniel Niederlöhner

John P Mugler, Iii

Vladimir Jellus

Michael Koehler

Michael Köhler

Thomas Kluge

Samuel W Fielden

Daniel Niederloehner

Uvo Hölscher

Uvo Hoelscher

Kirstin Jattke

Jun Bao

G Wilson Miller, Iv

Niels Oesingmann

William Curtis Howe

Rainer Kaim

Talissa A Altes

Eddy current induced magnetic fields (MF) are compensated in a magnetic resonance imaging system. An MR-sequence (M) includes a number of gradients. A dataset includes values of an amplitude and a time constant of eddy current fields of a number of gradients on at least one gradient axis. A number of points in time within the time period of the MR-sequence are defined. A number of constant currents are calculated for a number of coils of the magnetic resonance imaging system based on the dataset. The number of constant currents is designed to compensate at least at the one defined point in time (PT, PT). The calculated number of constant currents are applied on the related coils prior or during the application of the MR-sequence or a section of the MR-sequence.

Method and control unit for compensation of eddy current induced magnetic fields in magnetic resonance imaging

The present disclosure is directed to controlling a magnetic resonance imaging system for generating magnetic resonance image data from an object under examination, in which magnetic resonance raw data is captured, and at least one multi-slice STEAM pulse sequence is generated. The multi-slice STEAM pulse sequence comprises one excitation module for each slice, in each of which are generated a first slice-selective RF excitation pulse and a second slice-selective RF pulse, and one readout module for each slice for acquiring magnetic resonance raw data, which readout module comprises a third slice-selective RF pulse and further sequence elements for spatial encoding and for receiving RF signals. Between the excitation module and the readout module of a first slice is implemented at least one excitation module or one readout module for another slice.

MR imaging using an accelerated multi-slice steam sequence

In a method for operating a magnetic resonance (MR) facility during recording of MR data by using a MR sequence including a saturation module for a spin type to be saturated, in which a high-frequency saturation pulse is emitted between first and second spoiler gradient pulses, and multiple further gradient pulses apart from the spoiler gradient pulses, eddy current data is determined. The eddy current data describes eddy currents existing during emission of the saturation pulse and resulting from the further gradient pulses. Further, a pulse parameter of the first spoiler gradient pulse is selected based on the eddy current data such that the eddy currents generated by the first spoiler gradient pulse compensate for at least part of the eddy currents described by the eddy current data during emission of the saturation pulse. The facility is controlled to emit the first spoiler gradient pulse with the selected pulse parameter.

Method and system for operating a magnetic resonance facility

The disclosure relates to a method for triggered acquisition of a measured data set by a magnetic resonance system, to a corresponding computer program, to a corresponding data memory and to the corresponding magnetic resonance system. In the method, a cyclical signal is detected, which describes a cyclical change in a target object to be imaged. Cycles are automatically identified in this cyclical signal. Furthermore, at least one property of the cyclical signal is automatically determined. It is then automatically determined whether triggering of a single measurement for acquisition of some of the measured data set is permitted in an identified cycle of the cyclical signal. This determination is made as a function of the at least one determined property of the cyclical signal and a specified reference value of an acquisition parameter.

Method for triggered acquisition of a measured data set by a magnetic resonance system, computer program, data memory, and magnetic resonance system

In a method for filtering magnetic resonance (MR) image data, complex MR image data is acquired from a region to be imaged, and a sliding window averaging is applied to the complex MR image data to generate filtered MR image data. For each window position of the sliding window averaging: a phase variation of the complex MR image data of individual image points of a sliding window is estimated with a model using a linear phase progression, and filtered complex MR image data is generated based on the estimated phase variation of the complex MR image data. The generation of the filtered complex MR image data uses an average formation of the complex MR image data of the individual image points of the sliding window.

Linear phase-corrected local averaging of MR image data

Some aspects of the present disclosure relate to ultrashort-echo-time (UTE) imaging. In one embodiment, a method includes acquiring UTE imaging data associated with an area of interest of a subject. The acquiring comprises applying an imaging pulse sequence with a three-dimensional (3D) spiral acquisition and a nonselective excitation pulse. The method also includes reconstructing at least one image of the area of interest from the acquired UTE imaging data.

3D UTE imaging using variable-TE stack-of-spirals acquisition

In a method and magnetic resonance (MR) apparatus for performing an adjustment of the MR system, an examination object under is divided into at least one excitation volume. First adjustment parameters for the at least one excitation volume of the object, and second adjustment parameters for the at least one excitation volume of the object, which differ from the first adjustment parameters are determined. First MR signals are acquired from the at least one excitation volume using the first adjustment parameters. Second MR signals are acquired from an excitation volume using the second adjustment parameters. A first MR image of the at least one excitation volume is reconstructed using the first MR signal. A second MR image of the at least one excitation volume is reconstructed using the second MR signal.

Magnetic resonance apparatus and method for dynamic adjustment thereof with multiple adjustment parameters

In a method and apparatus for acquiring magnetic resonance (MR) data from a subject, excitation pulses and at least two refocusing pulses are applied to the subject in an MR scanner, and the MR scanner is operated to activate gradients in a readout direction that cause at least two gradient echoes to be formed between the at least two successive refocusing pulses, with a temporal distance between the at least two gradient echoes that produces a predetermined phase shift between a signal acquired from a first nuclei in the subject and a signal acquired from a second nuclei in the subject at times of the respective gradient echoes, and that include readout gradients associated respectively with a first and a last gradient echo, among said at least two gradient echoes, the readout gradients being asymmetrical.

Method and apparatus for acquiring magnetic resonance data

In a magnetic resonance imaging system and operating method for generating magnetic resonance image data of an object under examination, in order to acquire magnetic resonance raw data, an operating sequence is determined that has an excitation wherein an RF excitation pulse is radiated, and a readout procedure for receiving RF signals. In addition, a diffusion contrast gradient pulse sequence is generated that includes an uneven number of 2n+1 diffusion contrast gradient pulses switched in chronological succession, with the sum of the zeroth gradient moments of the diffusion contrast gradient pulses having the value zero and the sum of the first gradient moments of the diffusion contrast gradient pulses having the value zero. An RF refocusing pulse is switched between two of the diffusion contrast gradient pulses.

Method and magnetic resonance apparatus for speed-compensated diffusion-based diffusion imaging

In a method and a controller for generating a parameter map for a target volume in an examination object, that represents a field deviation from the resonance frequency of a first spectral component of tissue of object in a magnetic resonance tomography scanner, a spatial region of the object, which includes at least the target volume, is excited. At least three echo signals are formed, wherein a first echo time difference between two the echo signals is chosen such that the phase evolutions of the signals of a second spectral component of the tissue differ, during the first echo time difference, from the first spectral component substantially by 2&#x3c0;, and an echo time of at least a further one of the echo signals is chosen such that it lies between the echo times of the two echo signals having the first echo time difference. Raw data are then acquired from the three echo signals, and the parameter map is then generated therefrom.

Method and magnetic resonance apparatus for generating a parameter map to compensate local inhomogeneities in the basic magnetic field

In a method and magnetic resonance (MR) tomography system for generating image data of a subject to be examined, situated in an MR scanner, during a magnetic resonance measurement the subject is repeatedly moved back and forth relative to a magnet/gradient system of the MR scanning between a starting position and an end position. During this movement, portions of a total raw image data set, which is required for the reconstruction of image data for slices of an image stack in the subject, are in each case acquired in different sweeps from the starting position to the end position and/or from the end position to the starting position.

Magnetic resonance method and apparatus

In method for determining a radial k-space trajectory, having multiple spokes, of an MR control sequence, a first whole number (N) is selected from a first subset of whole numbers. A first constant angular increment (d&#x3a6;) between respective spokes of the radial k-space trajectory that are spatially adjacent in k-space is determined as the quotient of &#x3c0; and the first whole number N. Subsequently, a second constant angular increment (&#x394;k*d&#x3a6;) between spokes of the radial k-space trajectory that are measured sequentially in time is determined as the product from a second whole number (&#x394;k) and the first constant angular increment d&#x3a6;, wherein the second whole number &#x394;k is determined from a second subset of whole numbers. The first subset of whole numbers and/or the second subset of whole numbers are/is the set of prime numbers.

Dynamic method and apparatus for radial acquisition of magnetic resonance data

To enable improved reconstruction of magnetic resonance (MR) image data from MR scan data acquired from an examination object using dynamic shimming in an MR scanner that has a shim unit with at least one shim channel, an examination region of the object is divided into multiple sections, a B0 field of the examination region is scanned, and a B0 field map is thereby generated, a number of shim parameter sets are determined for the shim channel using the B0 field map, with a first shim parameter set of the number of shim parameter sets being determined for a first section of the multiple sections, and a second shim parameter set of the multiple shim parameter sets is determined for a second section of the multiple sections. MR scan data of the examination region are acquired, but before acquiring the MR scan data from the first section, the shim channel is adjusted using the first shim parameter set and, before acquiring the MR scan data from the second section, the shim channel is adjusted using the second shim parameter set. MR image data are reconstructed from the MR scan data using the first B0 field map and the number of shim parameter sets.

Method and apparatus for magnetic resonance imaging

A magnetic resonance control sequence with a pulse arrangement that acts selectively in at least two spatial directions in order to excite a limited rotationally symmetrical excitation profile within an examination subject has an RF excitation pulse formed as a sequence of multiple partial RF pulses, and gradient pulses in the two spatial directions that are coordinated with the partial RF pulses so that the RF energy introduction of different partial RF pulses in transmission k-space occurs on circular k-space transmission trajectories that are concentric to one another. The amplitude of the RF envelope of the partial RF pulses is constant during the duration of a traversal of each circular k-space trajectory. The control sequence can also be used in a calibration of a magnetic resonance system.

Method and device for determination of a magnetic resonance control sequence

To enable improved adjustment of at least one shim channel for magnetic resonance imaging of an examination region of an examination object by operation of a magnetic resonance apparatus that has a shim arrangement with a first shim channel volume having at least one first shim channel and a second shim channel volume having at least one second shim channel, the examination region is divided into multiple of sections, multiple first shim parameter sets are determined for the at least one first shim channel, with one first shim parameter set among the multiple first shim parameter sets being ascertained for each of the multiple sections, a second shim parameter set is ascertained for the at least one second shim channel, taking into account the ascertained multiple first shim parameter sets, and magnetic resonance image data of the examination region are acquired, but before this acquisition, the at least one second shim channel is adjusted using the second shim parameter set and the at least one first shim channel is adjusted for acquiring the magnetic resonance image data from a specific section of the multiple sections using a first shim parameter set ascertained for that specific section.

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Erlangen, Germany

Alto Stemmer