Patent classifications
G01R33/5613
Controlled excitation and saturation of magnetisation transfer systems
The present invention relate to a system and associate method of MRI and MR spectroscopy which provide stable measurements of the relaxation times, T1 and T2, by using tailored multi-band RF pulses that direct control of the saturation conditions in the background pool of macro-molecular protons, and hence provide a flexible means to induce constant Magnetisation Transfer (MT) effects. In doing this, equal saturation of the background pool is obtained for all measurements independent of the parameters that may be changed, for example, the rotation rate used to obtain a desired flip angle, that is, the degree of change in the magnetisation of the free pool of protons.
METHOD FOR RECORDING DIAGNOSTIC MEASUREMENT DATA OF A HEAD OF AN EXAMINATION OBJECT IN HEAD IMAGING VIA A MAGNETIC RESONANCE DEVICE
A method is proposed for recording diagnostic measurement data of a head of an examination object in head imaging via a magnetic resonance device. The method comprises performing an overview scan of the head of the examination object, wherein overview measurement data is acquired in the overview scan and performing various diagnostic scans of the head of the examination object based on the acquired overview measurement data, wherein diagnostic measurement data is acquired in the various diagnostic scans.
SYSTEM AND METHOD FOR MAGNETIC RESONANCE NEUROGRAPHY USING INTRAVENOUS ULTRASMALL SUPRAPARAMAGNETIC IRON OXIDE PARTICLES
Some implementations provide a method for imaging one or more peripheral nerves in a region of a subject, which method includes: introducing a dose of an iron-based agent into the subject, wherein the dose causes a reduction of a T2 relaxation time of the subject's blood; and acquiring, from a magnetic resonance imaging (MRI) scanner, one or more fluid-sensitive MRI images of the region of the subject that has received the dose. The magnetic resonance (MR) signals from the subjects blood in the region is substantially reduced in response to the dose of the iron-based agent.
Method for recording a magnetic resonance image dataset, data medium, computer program product, and magnetic resonance installation
A method for recording a magnetic resonance image dataset includes providing a magnetic resonance sequence with a series of sequence blocks, and providing at least one correction term to compensate for a magnetic field change. The magnetic field change is produced as a change of an actual magnetic field compared to a setpoint magnetic field by gradient pulses. The magnetic field change is established via a transfer characteristic of the gradient system of the magnetic resonance installation. The at least one correction term is used to compensate for the magnetic field change, and at least one magnetic resonance image dataset is recorded with the magnetic resonance sequence using the correction term.
Systems and methods for magnetic resonance imaging
A method for magnetic resonance imaging (MRI) may include cause, based on a pulse sequence, a magnetic resonance (MR) scanner to perform a scan on an object. The pulse sequence may include a steady-state sequence and an acquisition sequence that is different from the steady-state sequence. The steady-state sequence may correspond to a steady-state phase of the scan in which no MR data is acquired. The acquisition sequence may correspond to an acquisition phase of the scan in which MR data of the object is acquired. The method may also include generating one or more images of the object based on the MR data.
Systems and methods for spiral-in-out low field MRI scans
Systems and methods for performing ungated magnetic resonance imaging are disclosed herein. A method includes producing magnetic resonance image MRI data by scanning a target in a low magnetic field with a pulse sequence having a spiral trajectory; sampling k-space data from respective scans in the low magnetic field and receiving at least one field map data acquisition and a series of MRI data acquisitions from the respective scans; forming a field map and multiple sensitivity maps in image space from the field map data acquisition; forming target k-space data with the series of MRI data acquisitions; forming initial magnetic resonance images in the image domain by applying a Non-Uniform Fast Fourier Transform to the target k-space data; and forming reconstructed images with a low rank plus sparse (L+S) reconstruction algorithm applied to the initial magnetic resonance images.
Dual echo steady state MR imaging using bipolar diffusion gradients
A method of magnet resonance (MR) imaging of an object including: subjecting an object in an examination volume of an MR device to a dual echo steady state imaging sequence, a free induction decay signal (FID) and an echo signal (ECHO) being generated in each interval between two successive RF pulses, wherein a pair of diffusion gradient waveforms (GDIF) of equal phase integral and opposed polarity is applied in the interval between the FID signal and the echo signal; —acquiring the FID signals and the echo signals in a number of repetitions of the imaging sequence with varying phase encoding; and —reconstructing a diffusion weighted MR image from the acquired FID signals and echo signals.
SELECTION OF FREQUENCY OFFSET FOR AN MRI SCAN
A frequency offset is selected based on similarity measures of multiple MRI images obtained from frequency scout measurements associated with multiple frequency offsets from a reference frequency of a magnetization excitation pulse. The similarity measure for each respective MRI image of the multiple MRI images is determined based on a comparison between at least one reference image and the respective MRI image. The at least one reference image is determined from the multiple MRI images based on spectrum information of each of the multiple MRI images. Such methods facilitate automatically determining/selecting a more optimal frequency offset for an MRI scan following a frequency scout scan, in particular, for an SSFP or a bSSFP pulse sequence, and thereby banding artifacts and/or flow-related artifacts can be reduced for the MRI scan.
Multi-echo radial look-locker imaging for simultaneous T1 and fat fraction quantification
A method for using a multi-echo magnetic resonance imaging (MRI) simultaneously quantify T1 and fat fraction in an anatomical region of interest includes performing a radial single shot multi-echo acquisition of the anatomical region of interest. The radial single shot multi-echo acquisition comprises applying a preparation pulse to invert longitudinal magnetization of the anatomical region of interest, and acquiring a plurality of radial readouts at different echo times (TE). A magnetization recovery curve is continuously sampled using the plurality of radial readouts to yield a plurality of radial spokes. The radial spokes for each TE are ground together to generate under-sampled k-space data for each TE. The under-sampled k-space data is reconstructed into a plurality of multi-echo images corresponding to the different echo times. One or more fitting algorithms are applied to the multi-echo images to generate a water-only T1 map and a proton density fat fraction (PDFF) measurement.
A METHOD FOR MULTI-COMPONENT ANALYSIS ON MRI MEASUREMENT DATA
It is an object of present invention to provide for a faster method of multi-component analysis. This object is achieved by a method for multi-component analysis on MRI measurement data, wherein a component is defined by one or more tissue component parameters among which preferably one is a T2 or T1 value. The method comprising steps of receiving the MRI measurement data, wherein the MRI measurement data comprises multiple signals corresponding to multiple voxels in an MRI image and wherein the MRI measurement data is acquired by means of a sequence encoding the one or more tissue component parameters; identifying components in the multiple voxels by minimizing a difference between the multiple signals and a linear combination of weighted simulated temporal signal evolutions, wherein different simulated temporal signal evolutions represent different components and are based on different values of the one or more tissue component parameters, and wherein the identification of the components is performed under the assumption that the possible components are the same for all of the multiple voxels and wherein a higher total number of components is penalized over a lower total number of components, and wherein the simulated temporal signal evolutions are weighted by a weight factor that is non-negative.