Patent classifications
G01R33/5616
METHOD AND MAGNETIC RESONANCE APPARATUS FOR ACQUIRING MAGNETIC RESONANCE DATASET WITH REDUCED SUSCEPTIBILITY ARTIFACTS IN THE RECONSTRUCTION IMAGE
In a method and apparatus for recording a magnetic resonance dataset of a volume of interest of an object, at least one gradient moment is calculated as a function of at least one jump in susceptibility that is present in the volume of interest, between two sections of the volume of interest. An excitation pulse is radiated and at least one compensation moment is activated in a part volume of the volume of interest, for the at least partial compensation of a gradient moment caused by the jump in susceptibility. The signal generated by the excitation pulse is read out.
MR imaging with suppresion of flow artifacts
At least two gradient echo signals are generated at two different echo times by subjecting a portion of a body (10) in an MR examination region (1) to an imaging sequence of RF pulses and switched magnetic field gradients. The 0th moment of the readout magnetic field gradient essentially vanishes at the time of a first gradient echo while the 1st moment of the readout gradient is non-zero. Both the 0th and 1st moments of the readout magnetic field gradient essentially vanish at a time of a second gradient echo. Gradient echo signals are acquired. Acquiring the gradient echo signals is repeated for a plurality of phase encoding steps. A first MR image is reconstructed from the gradient echo signals of the first gradient echo and a second MR image is reconstructed from the gradient echo signals of the second gradient echo. Ghosting artefacts in the first and/or second MR image are identified by comparing the first and second MR images.
MAGNETIC RESONANCE APPARATUS AND METHOD FOR DYNAMIC ADJUSTMENT THEREOF WITH MULTIPLE ADJUSTMENT PARAMETERS
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.
Method and magnetic resonance apparatus for echo planar imaging with data entry into k-space along a zigzag trajectory
In a method and apparatus for echo planar magnetic resonance (MR) imaging sequence of phase encoding gradient fields and a sequence of readout gradient fields are applied in order to produce a well-defined zigzag-type trajectory for entering raw data into k-space. Zigzag-type trajectories can be achieved that have flanks without curvature, or without significant curvature. Cartesian methods for image reconstruction of parallel MR imaging are applied to echo planar MR imaging with such zigzag-type trajectories.
METHOD, CONTROLLER, AND MAGNETIC RESONANCE APPARATUS FOR MODEL-FREE DETERMINATION OF IMAGE REGIONS WITH ANOMALOUS DIFFUSION USING DIFFUSION-WEIGHTED MAGNETIC RESONANCE IMAGE DATA
In a magnetic resonance apparatus and a method and controller for operating such an apparatus, first and second diffusion-weighted image data are reconstructed from first and second diffusion-encoded raw data that were respectively acquired using different diffusion-encoding gradient pulse sub-sequences. The different sub-sequences differ by respectively having a different parameter that characterizes the respective sub-sequence as a function of time. The first and second reconstructed image data are compared and a deviation of the image data from normal Gaussian diffusion behavior is determined model-free on the basis of the comparison result.
Magnetic resonance imaging device, calculation device for generation of imaging parameter set, and imaging parameter set generation program
An MRI device for executing an imaging operation at least three times or more with a different combination of at least a repetition time and a flip angle in the same imaging sequence, includes: a receiving unit which receives information specifying an imaging target and a constraint condition relating to an imaging time or quantitative value accuracy; and a scan parameter set generation unit which calculates at least three or more scan parameter sets having a different combination of at least the repetition time and the flip angle on the basis of the constraint condition. The MRI device uses three or more scan parameter sets generated by the optimal scan parameter set generation unit and calculates quantitative values (T1, T2,and the like) of the imaging target from a plurality of images obtained by the imaging operation.
MAGNETIC RESONANCE IMAGING APPARATUS AND METHOD THEREOF
A magnetic resonance imaging (MRI) apparatus for obtaining a magnetic resonance (MR) image, based on a multi-echo sequence, and a method of the MRI apparatus are provided. The MRI apparatus includes a data obtainer configured to obtain first echo data, based on an echo that is generated at a first echo time, and obtain second echo data, based on an echo that is generated at a second echo time later than the first echo time, the first echo data including a part overlapping a part included in the second echo data in a k-space. The MRI apparatus further includes an image processor configured to reconstruct the MR image, based on the first echo data and the second echo data.
Method for simultaneous multi-slice magnetic resonance imaging
A method for multi-slice magnetic resonance imaging, in which image data is acquired simultaneously from multiple slice locations using a radio frequency coil array, is provided. By way of example, a modified EPI pulse sequence is provided, and includes a series of magnetic gradient field “blips” that are applied along a slice-encoding direction contemporaneously with phase-encoding blips common to EPI sequences. The slice-encoding blips are designed such that phase accruals along the phase-encoding direction are substantially mitigated, while providing that signal information for each sequentially adjacent slice location is cumulatively shifted by a percentage of the imaging FOV. This percentage FOV shift in the image domain provides for more reliable separation of the aliased signal information using parallel image reconstruction methods such as SENSE. In addition, the mitigation of phase accruals in the phase-encoding direction provides for the substantial suppression of pixel tilt and blurring in the reconstructed images.
SIMULTANEOUS DYNAMIC CONTRAST ENHANCED AND DYNAMIC SUSCEPTIBILITY MAGNETIC RESONANCE IMAGING USING MAGNETIC RESONANCE FINGERPRINTING
Described here are systems and methods for generating quantitative perfusion parameter maps based on multiple different relaxation parameter maps that are simultaneously produced from images acquired using contrast-enhanced magnetic resonance imaging (“MRI”) techniques.
Systems and methods for magnetic resonance imaging
Methods and apparatus for operating an MRI system is provided. The disclosure provides a diffusion-prepared driven-equilibrium preparation for an imaging volume and acquiring 3-dimensional k-space data from said prepared volume by a plurality of echoplanar readouts of stimulated echoes. An excitation radio-frequency signal and first and second inversion RF signals are provided to define a field-of-view (FOV).