Patent classifications
G01R33/5614
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.
Phase sensitive magnetic resonance angiography
The present invention includes a computerized method of detecting fluid flow in a vessel, the method comprising: obtaining at least one non-contrast enhanced magnetic resonance image from a magnetic resonance imager; performing a phase sensitive reconstruction of the at least one non-contrast enhanced magnetic resonance image using a processor; combining the phase sensitive reconstruction with a velocity selective preparation of the non-contrast enhanced magnetic resonance image, to determine using the processor, in a single acquisition, at least one of: a flow direction of a fluid in the vessel, a reduction or elimination of a background signal, body fat, water/fat separation, or differentiation of a fast moving flow signal from a slow moving flow signal in an opposite direction with suppression of the background signal; and storing or displaying at least one of flow direction or flow strength of the fluid flow in the vessel obtained from the single acquisition.
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.
Method and Device for Magnetic Resonance Imaging Pre-Scan, and Magnetic Resonance Imaging System
Techniques for MRI pre-scan method may automatically determine and apply a compensation frequency to correct for inhomogeneous magnetic fields, improving the efficiency and quality of clinical examinations. The method may include executing a first pulse sequence with an MRI system, acquiring multiple magnetic resonance signals at different offset frequencies from the same location, and recording corresponding k space data. Variations between the k space data may be calculated and used to determine the compensation frequency. By applying the compensation frequency to correct for inhomogeneous magnetic fields, artifacts in MRI images can be eliminated, resulting in higher quality images. This method offers a quantitative and automated solution for compensating for inhomogeneous magnetic fields during MRI pre-scans, improving the accuracy and efficiency of clinical examinations. The invention also includes a dedicated MRI pre-scan device. The system and method have broad applications in the field of medical imaging.
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.
Multicontrast synthetic late gadolinium enhancement imaging using post-contrast magnetic resonance fingerprinting
Methods and systems generate synthetic late gadolinium enhancement (LGE) magnetic resonance images using a magnetic resonance fingerprinting (MRF) acquisition. From a single acquisition, MRF image data is obtained, including co-registered T.sub.1 and T.sub.2 tissue property maps. Different tissue regions of interest are identified, such as viable myocardium, scar, and blood and T.sub.1 and T.sub.2 values for each are determined. Based on these, different sets of pulse sequence parameters are determined, e.g., using different synthetic image contrast models receiving the MRF image data. Synthetic LGE images at different contrasts are generated as a result, including a synthetic bright-blood LGE image, a synthetic dark-blood/gray-blood LGE image, and a synthetic optimized imaged.
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.
MRI system, and method and device for determining waveform of oblique scanning
The present disclosure relates to an MRI system and a method and device for determining a waveform of oblique scanning. Specifically, provided are a magnetic resonance imaging system, a method and device for determining a gradient waveform of oblique scanning, and a computer-readable storage medium. The method includes: generating an initial physical axis gradient waveform on a physical axis, the physical axis including a first physical axis, a second physical axis, and a third physical axis, wherein gradient waveforms on the three physical axes have the same inflection time; converting the initial physical axis gradient waveform into a logical axis gradient waveform, an inflection point of the logical axis gradient waveform being the same as the inflection time of the initial physical axis gradient waveform; re-converting the logical axis gradient waveform into a physical axis gradient waveform; and using, during the oblique scanning of magnetic resonance imaging, the converted physical axis gradient waveform to drive a gradient amplifier.
System and method for improved magnetic resonance fingerprinting using inner product space
A system and method is provided for improved magnetic resonance fingerprinting (MRF) data dictionary matching using an MRF dictionary having entries with an inner product storing tissue properties.