Patent classifications
G01R33/4824
Magnetic resonance imaging apparatus
In one embodiment, a magnetic resonance imaging apparatus includes: a scanner that includes a static magnetic field magnet configured to generate a static magnetic field, a gradient coil configured to generate a gradient magnetic field, and a WB (Whole Body) coil configured to apply an RF pulse to an object; and processing circuitry. The processing circuitry is configured to: set (i) a pulse sequence in which a sequence element is repeated, the sequence element including at least an inversion pulse and (ii) a data acquisition sequence executed after a delay time from the inversion pulse; and cause the scanner to execute the pulse sequence by using virtual gating.
MR fingerprinting having adjustable measurement time
MR fingerprinting method in which an MR pulse sequence succession is output multiple times. The MR pulse sequence succession has MR pulse sequences of a same type output successively in time and differing in terms of a pulse sequence parameter that is varied according to a predefined scheme. During the first output, raw data from a region of interest (ROI) of an object is acquired in a short time interval by the raw data being acquired at a low information density. The total information density of the acquisition is increased with each repetition of the output. After the acquisition, image data from the ROI is reconstructed based on the acquired raw data. MR-parameter value datasets associated with reference image data and having MR parameter values, are determined by comparing the reconstructed image data with the reference image data. MR parameter maps are determined based on the determined MR parameter values.
Generation of measurement data from a target volume of an examination subject using a magnetic resonance system
In a method and system for the generation of measurement data required k-space is read out in the readout direction in k-space rows such that at least a first k-space row of the k-space rows does not cover the k-space to be read out in the readout direction in full and at least a second k-space row of the k-space rows covers the k-space to be read out in locations in the readout direction at which the first k-space row does not cover the k-space to be read out. Measurement data that is missing in the k-space is completed in this way on the basis of recorded echo signals stored as measurement data.
Magnetic resonance imaging method and device based on balanced steady state free precession sequence
Techniques are disclosed based on balanced steady state free precession sequence. The techniques include determining a readout gradient of climbing period, platform period, and descent period, and performing a balanced steady state free precession sequence in which the readout gradient is applied in the readout direction, the analog-to-digital conversion module for collecting k-space data is activated during the climbing period maintained in the on state during the platform period, and deactivated during the descent period. The technique includes converting the k-space data collected by the analog-to-digital conversion module into uniform k-space data and generating a magnetic resonance image based on the uniform k-space data. The techniques yield more running time of the readout gradient for data acquisition, reduce the data reading time, and shorten the scanning time. The techniques also reduce the accumulated phase of the field non-uniformity in the echo interval to reduce black band artifacts.
SYSTEMS AND METHODS FOR LOW-FIELD FAST SPIN ECHO IMAGING
A magnetic resonance imaging (MRI) system and method for acquiring magnetic resonance (MR) images using a pulse sequence implementing driven equilibrium and quadratic phase cycling techniques is provided. The method includes, during a pulse repetition period of a pulse sequence and using a quadratic phase cycling scheme, applying a first RF pulse to deflect a net magnetization vector associated with the subject from a longitudinal plane into a transverse plane; after applying the first RF pulse, applying a first sequence of RF pulses each of which flips the net magnetization vector by approximately 180 degrees within the transverse plane; and after applying the first sequence of RF pulses, applying a second RF pulse to deflect the net magnetization vector from the transverse plane to the longitudinal plane.
Magnetic resonance imaging method and magnetic resonance imaging system
The present disclosure is directed to MRI techniques. The techniques include occupying a central region of a first k-space with full sampling along a Cartesian trajectory, occupying a peripheral region of the first k-space with undersampling along a non-Cartesian trajectory; acquiring sensitivity distribution information of receiving coils; based on a sensitivity distribution chart, merging the Cartesian data of the central region according to multiple channels to obtain a third k-space; based on the sensitivity distribution chart, applying parallel imaging and compressed sensing to the undersampled non-Cartesian trajectory to reconstruct an image, obtaining a second k-space by transformation, and when the second k-space and third k-space are synthesized, using a central region of the second k-space to replace the third k-space of a corresponding region to obtain a k-space suitable for image reconstruction.
METHODS FOR MULTI-SLICE AND MULTI-CONTRAST MAGNETIC RESONANCE IMAGING WITH JOINT IMAGE RECONSTRUCTION AND COMPLEMENTARY SAMPLING SCHEMES
Image reconstruction methods for multi-slice and multi-contrast magnetic resonance imaging with complementary sampling schemes are provided, comprising: data acquisition using complementary sampling schemes between slices or/and contrasts) in spiral imaging or Cartesian acquisition; joint calibrationless reconstruction of multi-slice and multi-contrast data via block-wise Hankel tensor completion.
Method for acquiring measurement data using a magnetic resonance system with correction of k-space trajectories
In a method for acquiring measurement data using a magnetic resonance (MR) system having a gradient unit, frequency-dependent parameters characterizing the gradient unit of the MR system are accessed (e.g. loaded from a memory), a k-space trajectory of a RESOLVE (Readout Segmentation Of Long Variable Echo trains) sequence planned for a MR measurement is accessed, MR measurement data is acquired based on the planned k-space trajectory and reconstructing image data from the MR measurement data, and an electronic signal is provided that represents the reconstructed image data as an output of the MR system. The k-space trajectory may have a frequency component in at least one direction. The planned k-space trajectory may be corrected based on at least one frequency component of the planned k-space trajectory and the frequency-dependent parameters.
System and method for automated transform by manifold approximation
A system may transform sensor data from a sensor domain to an image domain using data-driven manifold learning techniques which may, for example, be implemented using neural networks. The sensor data may be generated by an image sensor, which may be part of an imaging system. Fully connected layers of a neural network in the system may be applied to the sensor data to apply an activation function to the sensor data. The activation function may be a hyperbolic tangent activation function. Convolutional layers may then be applied that convolve the output of the fully connected layers for high level feature extraction. An output layer may be applied to the output of the convolutional layers to deconvolve the output and produce image data in the image domain.
Method and device for magnetic resonance imaging, and corresponding computer program product
In a Method and a device for magnetic resonance imaging of a subject using a spoiled gradient echo sequence, a B.sub.0 magnetic field strength of at most 1.5 T is used during the sequence. As part of the sequence a slice select gradient acting as a spoil gradient is played out. Substantially simultaneously with the slice select gradient a predetermined RF pulse is played out in the sequence, wherein a time-bandwidth product of the RF pulse is set so that a majority of the energy of the RF pulse is transmitted in its central main lobe.