Patent classifications
G01R33/5613
Computer-implemented method of building a database of pulse sequences for magnetic resonance imaging, and a method of performing magnetic resonance imaging using such a database
A computer-implemented method of building a database of pulse sequences for parallel-transmission magnetic resonance imaging, includes a) for each of a plurality of subjects, determining an optimal sequence for the subject; b) for each subject, computing the values of the or of a different cost or merit function obtained by playing the optimal sequences for all the subjects; c) aggregating the subjects into a plurality of clusters using a clustering algorithm taking the values, or functions thereof, as metrics; d) for each cluster, determining an averaged optimal sequence for the cluster; e) receiving, as input, a set of features characterizing an imaging subject, comprising at least a morphological feature of the subject; f) associating the subject to one pulse sequence of the database based on the set of features using the computer-implemented classifier algorithm; and g) performing magnetic resonance imaging using the pulse sequence. A magnetic resonance imaging apparatus for carrying out steps e)-g) of such a method is also provided.
SYSTEM AND METHOD FOR RECORDING A POSITRON EMISSION TOMOGRAPHY IMAGE DATA SET
In a method for recording a PET image data set, an overall recording area is moved continuously through the FOV at a constant movement speed, an attenuation map of the overall recording area being used to reconstruct the PET image data record from the PET raw data. The magnetic resonance data of a slice of the patient currently located within the FOV and movement status information relating to a cyclical movement of the patient are recorded simultaneously with recording the PET raw data. A movement status class is assigned to the PET raw data and the magnetic resonance data in each case. Using the magnetic resonance data assigned to the different movement status classes, attenuation maps of the patient are determined for the different movement status classes and applied to the PET raw data assigned to the corresponding movement status class to reconstruct the PET image data set.
Synchronization devices and methods for synchronizing imaging systems and stimulation systems
Examples described herein may provide for pre-triggering imaging scans (e.g. fMRI scans) using an electronic timer synchronized to a stimulation system.
Method and computer for producing a pulse sequence for controlling a magnetic resonance imaging apparatus
In a method and magnetic resonance apparatus for generating a B.sub.0 map of a region of interest, a magnetic resonance data set containing a number of image data sets is obtained and provided in a computer, wherein the image data sets are recorded using at least two measurement sequences and the mutually corresponding pixels of the image data sets each represent a time-dependent signal evolution. A B.sub.0 map of the region of interest is generated by the computer from the image data sets, wherein the B.sub.0 value of a pixel of the B.sub.0 map is determined from the associated signal evolution.
Magnetic resonance imaging using additional gradient pulses
Method for MR imaging of an acquisition region during a patient examination. In order to determine a point spread function, in a prior measurement for each of additional gradient output directions, the method includes choosing, in the acquisition region, a slice lying outside of an isocenter of the MR device, which slice extends in a plane perpendicular to the additional gradient output direction under consideration; following a respective slice-selective excitation of the selected slice, acquiring first calibration data using the additional gradient pulse of the additional gradient output direction under consideration, and acquiring second calibration data omitting the additional gradient pulse in each case along a k-space line, wherein a same timing sequence of additional gradient pulse and readout time window is used as in the MR sequence; and calculating, from the first and second calibration data, the point spread function for the additional gradient output direction under consideration.
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.
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.
Automated cardiac volume segmentation
Systems and methods for automated segmentation of anatomical structures, such as the human heart. The systems and methods employ convolutional neural networks (CNNs) to autonomously segment various parts of an anatomical structure represented by image data, such as 3D MRI data. The convolutional neural network utilizes two paths, a contracting path which includes convolution/pooling layers, and an expanding path which includes upsampling/convolution layers. The loss function used to validate the CNN model may specifically account for missing data, which allows for use of a larger training set. The CNN model may utilize multi-dimensional kernels (e.g., 2D, 3D, 4D, 6D), and may include various channels which encode spatial data, time data, flow data, etc. The systems and methods of the present disclosure also utilize CNNs to provide automated detection and display of landmarks in images of anatomical structures.
Low-field diffusion weighted imaging
Methods and apparatus for operating a low-field magnetic resonance imaging (MRI) system to perform diffusion weighted imaging, the low-field MRI system including a plurality of magnetics components including a B.sub.0 magnet configured to produce a low-field main magnetic field B.sub.0, at least one gradient coil configured to, when operated, provide spatial encoding of emitted magnetic resonance signals, and at least one radio frequency (RF) component configured to acquire, when operated, the emitted magnetic resonance signals. The method comprises controlling one or more of the plurality of magnetics components in accordance with at least one pulse sequence having a diffusion-weighted gradient encoding period followed by multiple echo periods during which magnetic resonance signals are produced and detected, wherein at least two of the multiple echo periods correspond to respective encoded echoes having an opposite gradient polarity.
System and method for semi-projective quantitative flow imaging using accelerated arterial spin-labeled cine MRI
A system and method for controlling a magnetic resonance imaging (MRI) system to create magnetic resonance (MR) cine angiograms of a subject. The method includes controlling the MRI system to acquire MR data from the subject by performing at least one cine acquisition pulse sequence having a plurality of acquisition RF pulse modules applied at constant intervals throughout a cardiac cycle, and at least one labeling pulse sequence including a first and a second /2 module and a labeling RF pulse module for labeling a region of inflowing arterial flow through a vessel of interest. The method further includes reconstructing the MR data to form a series of cine frames that form a cine angiogram, subtracting at least one cine frame from other cine frames reconstructed from the MR data, and displaying the MR cine angiogram of the vessel of interest.