27 results about "Gradient echo" patented technology

The embodiment of the invention provides a magnetic resonance imaging method and related equipment. The magnetic resonance imaging method comprises the following steps: applying a multi-spin echo sequence in each magnetization reset period, and collecting a group of multi-spin echo data sets until M groups of multi-spin echo data sets are obtained; after each magnetization reset period, a T1rho preparation pulse with spin locking duration is applied, then a multi-gradient echo sequence is applied, a group of multi-gradient echo data sets are collected until M groups of multi-gradient echo data sets are obtained, and the M groups of multi-spin echo data sets and the M groups of multi-gradient echo data sets correspond to M different spin locking durations respectively; and performing fitting operation on the M groups of multi-spin echo data sets and the M groups of multi-gradient echo data sets to generate a quantitative atlas. According to the technical scheme, the problems that a traditional T1rho sequence is long in scanning time, low in signal-to-noise ratio and single in contrast ratio are effectively solved, and the technical effects of time multiplexing and multi-contrast imaging are achieved.

The invention is suitable for the technical field of magnetic resonance chemical exchange saturation transfer imaging, and provides a magnetic resonance chemical exchange saturation transfer imaging method, device, equipment, product and storage medium. A gradient echo sequence is adopted to collect saturated water molecule signals, and the collected water molecule signals are stored in a K space; and wave control coding is introduced in the acquisition process, and a CEST image is reconstructed based on a water molecule signal of a K space. The introduction of wave control coding can reduce the scanning time. Due to the fact that the wave control coding sampling efficiency is high, a larger matrix size can be supported within the same time, high-resolution imaging is achieved, the partial volume effect can be relieved, and CEST quantitative accuracy is improved.

A method according to the invention for acquiring T2*-weighted measurement data of a test object using a magnetic resonance system comprises the steps: - irradiating a first RF excitation pulse to excite spins in a first layer in the test object, - switching gradients to generate at least one gradient echo signal, - after an echo time following the irradiation of the first RF excitation pulse, acquiring a first gradient echo signal from the first layer, - after the irradiation of the first RF excitation pulse and before the elapsed echo time following the first RF excitation pulse, irradiating at least one further RF excitation pulse to excite spins in a further layer,wherein, before the application of a further RF excitation pulse and after each RF excitation pulse preceding the further RF excitation pulse, a pre-rephasing gradient of a moment corresponding to the further RF excitation pulse following the pre-rephasing gradient is switched, - recording generated further gradient echo signals from further layers. By switching the pre-rephasing gradients according to the invention, gradient echo signals of the spins of different layers excited by the first RF excitation pulse and the at least one further RF excitation pulse can be separated. Thus, the echo time TE, which elapses until a first gradient echo signal is measured after the first RF excitation pulse, can be used to generate and measure further gradient echo signals in further layers after the first gradient echo signal, which increases the readout efficiency.

This application discloses a magnetic resonance chemical exchange saturation transfer imaging method, system, device, and storage medium. The method includes: applying a radio frequency saturation pulse for a first preset time to a region to be detected; applying a radio frequency echo pulse to the region to be detected and acquiring several gradient echo signals generated after activation by the radio frequency echo pulse; and using radial sampling to read the gradient echo signals along a preset direction to generate a magnetic resonance image. Through this method, this application effectively shortens the signal acquisition time by using gradient echo readings, effectively suppresses motion artifacts by using radial acquisition, and applies post-processing methods such as fitting to the acquired chemical exchange saturation transfer imaging spectral data to achieve water-lipid signal separation and extract and analyze the target signal.

A method for generating an image of a subject with a magnetic resonance imaging (MRI) system includes receiving MR image data acquired with the MRI system, wherein the MR image data comprises first gradient echo data and second gradient echo data and determining a linear phase error estimate. The linear phase error estimate may be based on all of the MR image data or a subvolume thereof, and may include calculating a pixel phase error for each of a plurality of pixels within the MR image data and determining a mean of the pixel phase error. Corrected MR image data is generated based on the linear phase error estimate, and then a water image and / or a fat image based on the corrected MR image data.

Disclosed herein is a medical system (100) comprising a magnetic resonance imaging system (102). The execution of the machine executable instructions (140) causes a computational system (132) to: control (200) the magnetic resonance imaging system with multi-echo gradient echo pulse sequence commands to acquire the k-space data (144), form (202) a first k-space data group (146) by aggregating a first selected k-space data portion, form (204) a second k-space data group (148) by aggregating a second selected k-space data portion, form (206) at least one additional k-space data group (150) by aggregating an additional selected k-space data portion; reconstruct (208) a first Dixon water image (152) from the first k-space data group, reconstruct (210) a second Dixon water image (154) from the second k-space data group, and reconstruct (212) an additional magnetic resonance image (156) from each of the at least one additional k-space data group.

This application discloses a system and method for processing precise synthetic CT images of the spine based on deep learning algorithms for axial spondyloarthritis. The system includes: a data acquisition unit for acquiring three-dimensional T1-weighted multi-gradient echo sequences, T2-weighted sequences, and water-lipid separation sequences obtained from magnetic resonance imaging of the target user's spine; a spatial registration unit for inputting multi-sequence data into a deformable registration network to perform spatial registration of multimodal features; a feature processing unit for fusing the registered multimodal features and performing dual-domain splitting based on an anatomical attention gating mechanism to obtain skeletal features and soft tissue features; and an image fusion unit for synthesizing synthetic CT images with HU values ​​corresponding to the target user's spine based on skeletal features and soft tissue features, achieving radiation-free, high-precision CT image acquisition, which can meet the diagnostic and grading requirements of axial spondyloarthritis while reducing the impact of radiation on the target user.

An ablation calculation method and an ablation calculation system, the ablation calculation method comprising: scanning a target to be measured using a gradient echo sequence containing i different echo times, obtaining a phase map corresponding to the echo time, i being a positive integer greater than or equal to 2 (S101); selecting at least two groups of phase maps corresponding to different echo times to obtain corresponding temperature difference maps (S102); obtaining a temperature map according to the temperature difference maps (S103); calculating an ablation condition according to the temperature map (S104); and the ablation calculation system comprising an ablation calculation module capable of executing the ablation calculation method.

A method of acquiring magnetic resonance (MR) data from a subject using a magnetic resonance imaging (MRI) system includes generating, for each of at least one level in the subject, a first pre-saturated RF pulse having a first flip angle, generating, after each first pre-saturated RF pulse, a series of first gradient echo sequences, and calculating a B0 value for each of the at least one level. A second pre-saturated RF pulse having a second flip angle is generated for each of the at least one planes in the subject, then a series of second gradient echo sequences is generated, and B1 is calculated for each of the at least one planes based on the first gradient echo sequences and the second gradient echo sequences.

The application discloses a kind of optimization methods of residual magnetism measurement process in magnetic resonance imaging system, adopt positive and negative combination gradient as test gradient, the difference of the action of spin echo and gradient echo is combined with magnetic field inhomogeneity, the change of magnetic field uniformity caused by test gradient is measured, then the change of echo peak caused by the change is used to measure the strength of residual magnetism.The method avoids the reference test under the condition that test gradient is zero, overcomes the adverse effects of magnetic hysteresis on reference signal, ensures that the magnetic field distribution state when collecting echo signal in measurement process is determined and stable, eliminates the influence of test sequence on test result, so as to improve the accuracy and stability of residual magnetism measurement result.The method of the application is simple and easy to operate, can measure the spatial anisotropy of residual magnetism, can be used to evaluate the influence of residual magnetism on imaging space positioning, and is especially suitable for judging whether permanent magnetic resonance imaging system meets the requirements of space positioning for monitoring and navigation in interventional therapy.

The invention provides a magnetic resonance parameter determination method and device, electronic equipment and a computer program product, and the method comprises the steps: scanning a scanning object through employing a plurality of gradient echo sequences of different repetition times, and obtaining a magnetic resonance image corresponding to the gradient echo sequence of each repetition time; the radio frequency flip angles set by the plurality of gradient echo sequences are the same; performing nonlinear fitting according to a plurality of different repetition times, a radio frequency flip angle set by the gradient echo sequence, the signal intensity of each magnetic resonance image and a preset signal model to determine a longitudinal relaxation time constant, the independent variables of the signal model including the repetition time and the longitudinal relaxation time constant, the dependent variable of the signal model is the signal intensity of the magnetic resonance image. Therefore, the gradient echo sequences with the same flip angle and different repetition times are adopted for scanning, and nonlinear fitting is performed based on the steady-state signal model, so that the longitudinal relaxation time constant can be quickly and accurately determined without long waiting time.

The application discloses a kind of quantitative magnetic susceptibility imaging method and device based on radial sampling, comprising: by magnetic resonance scanner executes three-dimensional gradient echo multi-echo sequence, and the three-dimensional k space multi-echo data of tissue is collected in radial sampling mode;The three-dimensional k space multi-echo data collected is corrected and density is compensated to obtain the three-dimensional k space multi-echo data and corrected track RT after track correction and density compensation;The three-dimensional k space multi-echo data and corrected track RT after track correction and density compensation are input into non-uniform fast Fourier transform reconstruction complex image, to obtain corresponding amplitude diagram and phase diagram;Phase diagram is unwound and background field is removed, to obtain corresponding local field;By improved sparse linear equation and least square method ILSQR algorithm inversion local field, corresponding magnetic susceptibility distribution diagram is generated.The method and device of the application reduce the influence of motion artifact, improve imaging quality and diagnostic accuracy.

The invention relates to a method of MR imaging of a body (10) of a patient located in an examination volume of an MR device (1). It is an object of the invention to provide a method which enables a geometrically corrected MR-only radiotherapy planning with a minimum number of scans. The method of the invention comprises the following steps: acquiring first MR imaging data representing at least one region of the body (10); analyzing the first MR imaging data to delineate at least one anatomical structure within the body region; acquiring second MR imaging data of the body region using a multi-point Dixon sequence; deriving a B0 map from the second MR imaging data; analyzing the B0 map to determine at least one low-fidelity region of the B0 map; performing a B0 mapping using a multi-shot gradient echo sequence limited to at least one region which fully or partially overlaps with the delineated anatomical structure and the low-fidelity region to refine the B0 map; and, correcting geometric distortions in the first and / or second MR imaging data using the refined B0 map. Furthermore, the invention relates to an MR device (1) for performing the method and to a computer program to be executed on an MR device (1).

The application discloses a reconstruction method of planar echo imaging, comprising the following steps: S1, collecting planar echo data and multi-echo gradient echo data of a region to be imaged respectively; S2, performing inverse geometric correction on the multi-echo gradient echo data to generate corrected data; and S3, performing image reconstruction according to the corrected data and the planar echo data to generate an imaging image. The application has the beneficial effect that the correction of the planar echo image is realized by collecting multi-echo gradient echo data and calculating a B0 field, the problem of possible artifacts in the calibration process of the planar echo imaging in the prior art is avoided, and the image of the planar echo imaging is clearer. Meanwhile, the multi-echo gradient echo data is used for coil sensitivity correction, the scanning speed is higher, and the calibration time can be effectively shortened.

This invention provides a magnetic resonance imaging (MRI) apparatus and its control method. In contrast-enhanced MRI, it improves the ability to depict tissues reached by the contrast agent and shortens the overall imaging time. The imaging unit of the MRI apparatus is equipped with a gradient echo pulse sequence for acquiring T1-emphasis images containing fat-suppressing pulses. The control unit performs the following control: the imaging unit repeats the pulse sequence for a given time from the time the contrast agent is administered to the subject, generating images of multiple phases at different arrival locations of the contrast agent. At this time, starting from the phase about to reach the target tissue, a preparatory pulse is added before the pulse sequence to suppress signals from the contrast agent present outside the target tissue (cells).

The invention discloses a magnetic resonance cis-diamagnetic source separation imaging method based on self-supervised learning, and belongs to the field of medical imagines.The method comprises the steps that a total magnetic susceptibility image and a transverse relaxation rate image are obtained through multi-gradient echo data; constructing a deep learning model fused with physical constraints, taking the two images as input, and training the model in a self-supervised mode to learn intermediate parameters changing along with space; and finally, calculating according to the parameters and a physical relational expression to obtain a high-precision paramagnetic substance distribution diagram and a high-precision diamagnetic substance distribution diagram. According to the method, a time-consuming spin echo sequence does not need to be additionally collected, the scanning time is remarkably shortened, and more accurate and efficient quantitative separation and analysis of brain iron deposition and myelin sheath change are achieved.

The invention relates to a magnetic resonance imaging method, device and equipment, a readable storage medium and a program product. The method comprises the following steps: acquiring a to-be-scanned imaging sequence; the to-be-scanned imaging sequence is a gradient echo sequence; the gradient echo sequence comprises a pre-dispersed phase gradient and a readout gradient applied after the pre-dispersed phase gradient; pre-scanning the detection object by using the to-be-scanned imaging sequence to obtain pre-scanning data; the pre-scanning data are data without phase coding; determining a low-energy region and a high-energy region of the K space according to the pre-scanning data; in response to the fact that an echo signal truncation region corresponding to the to-be-scanned imaging sequence is located in a high-energy region, reversing the polarity of the readout gradient and the polarity of the pre-dispersed phase gradient in the to-be-scanned imaging sequence to obtain an adjusted scanning imaging sequence; and performing imaging scanning on the detection object by using the adjusted scanning imaging sequence to obtain imaging data. By adopting the method, the quality of the magnetic resonance image can be improved.

A medical imaging method is disclosed herein. The method includes receiving (202) gradient echo magnetic resonance imaging data (123) describing a breast region (319) of a subject (318). The method also includes receiving (202) DIXON magnetic resonance imaging data describing the breast region. The DIXON magnetic resonance imaging data and the gradient echo magnetic resonance imaging data are spatially matched. The method also includes generating (204) a breast microcalcification magnetic resonance image (128) by inputting the gradient echo magnetic resonance imaging data and the DIXON magnetic resonance imaging data to a breast microcalcification image reconstruction module (122). The breast microcalcification image reconstruction module is configured to output a breast microcalcification magnetic resonance image in response to inputting the gradient echo magnetic resonance imaging data and the DIXON magnetic resonance imaging data. The breast microcalcification magnetic resonance image describes a location of breast microcalcification, wherein the gradient echo magnetic resonance imaging data is a phase image.

The application discloses a kind of based on short gradient echo's quantitative susceptibility imaging acceleration scanning method, belong to medical image scanning field, comprising: design suitable for short echo data scanning parameter;Construct the denoising diffusion probability model containing forward noise and reverse denoising process, the reverse denoising process embeds wavelet transform module;Extract short echo data from the full echo data of multiple gradient echo sequence, train the denoising diffusion probability model based on the short echo data, obtain the trained denoising diffusion probability model;In magnetic resonance imaging system, the scanning parameter is configured;Based on the short echo quantitative susceptibility imaging data of configured scanning parameter acquisition;The short echo quantitative susceptibility imaging data of acquisition is input into the trained denoising diffusion probability model, and reconstructs quantitative susceptibility image.The application can greatly reduce the existing quantitative susceptibility reconstruction scanning time by scanning parameter setting and deep learning model optimization reconstruction, and keep consistent image quality.

The application discloses a remanence measuring method based on magnetic resonance echo phase shift difference. In the method, the test direction is the same as the scanning direction, the difference between the action of the magnetic field non-uniformity on the spin echo and the gradient echo is utilized, the change of the magnetic field uniformity caused by the test gradient is measured, and the remanence intensity is measured by using the difference between the phase changes of the two echoes caused by the change. The method overcomes the problem that the multi-path gradient is not completely balanced to affect the test gradient and further affect the remanence measurement, eliminates the influence of the flat echo signal peak shape and the peak value drop on the measurement accuracy and stability, and guarantees the effectiveness of the test in the non-coordinate axis direction. In addition, the method does not need additional measuring instruments, the measuring process is simple and easy to implement, and the spatial anisotropy of the remanence can be measured. The method can be used for evaluating the influence of the remanence on the imaging space positioning, and is particularly suitable for judging whether the permanent magnetic resonance imaging system meets the requirements of the space positioning for monitoring and navigation in the interventional treatment.

A method for acquiring magnetic resonance (MR) data from a subject with a magnetic resonance imaging (MRI) system includes generating a first pre-saturation RF pulse having a first flip angle for each of at least one slice in the subject, generating a series of first gradient echo sequences following each first pre-saturation RF pulse, and calculating a B0 value for each of the at least one slice. A second pre-saturation RF pulse having a second flip angle is generated for each of the at least one slice in the subject, followed by a series of second gradient echo sequences, and a B1 is calculated for each of the at least one slice based on the first gradient echo sequences and the second gradient echo sequences.

The invention provides a craniocerebral multi-frequency conductivity tensor modeling method and system, a medium and electronic equipment. The method comprises the following steps: generating craniocerebral high-frequency conductivity based on a craniocerebral ultra-short echo sequence; diffusion microstructure parameters of the brain are obtained based on the multi-excitation diffusion weighted sequence; generating a low-frequency conductivity tensor of the brain based on the high-frequency conductivity and the diffusion microstructure parameters; generating a multi-frequency conductivity tensor based on the high-frequency conductivity and the low-frequency conductivity tensor; preparing a rapid gradient echo sequence based on the magnetization of the brain to generate a digital head model; and generating a craniocerebral intermediate frequency conductivity tensor model based on the multi-frequency conductivity tensor and the digital head model. According to the craniocerebral multi-frequency conductivity tensor modeling method and system, the medium and the electronic equipment, the individualized craniocerebral multi-frequency conductivity tensor model can be accurately constructed, so that support is provided for target planning and dose evaluation of a tumor treatment field.

The present disclosure provides a single-plane magnetic resonance imaging system including multiple components. The present disclosure also provides a method for generating multidimensional images by using the imaging system. The present disclosure also provides a method for applying multiple xSPEN readout gradients to the single-plane magnetic resonance imaging system disclosed herein. Several techniques exist for acquiring dynamic magnetic resonance (MR) images. Images can be acquired and generated in a small time window by rapidly sampling the entire k-space using a fast pulse sequence. For example, a spiral orbital gradient echo sequence can be used to sample the entire k-space in tens of milliseconds. Another approach uses small flip angle excitation to rapidly acquire lines in k-space. These approaches can also be combined with undersampling to further speed up image acquisition.

The invention discloses a resting state local brain function index description method based on a T2 * time sequence and an abnormal brain activity positioning device. According to the resting state local brain function index description method, a multi-echo gradient echo sequence is adopted for magnetic resonance data collection, multiple signals of different echo time are collected after radio frequency pulse excitation each time, T2 * values at all time points are fitted by applying a single-index attenuation model, T2 * time sequences are spliced in sequence, and the rest state local brain function indexes are obtained. And then low-frequency amplitude ALFF and a local consistency ReHo index are calculated, a resting state local brain function is described, and support is provided for accurate and reliable positioning of abnormal brain activities. The abnormal brain activity positioning device positions abnormal brain activities by comparing resting state local brain function indexes of different subjects. According to the method, the signals are automatically separated into the nerve correlation signals and the physiological noise through a physical model, and the method has specificity discovery capability and higher repeatability in a deep brain area and an area with serious magnetic sensitive artifacts.

The application provides a kind of brain multi-frequency conductivity tensor modeling method, system, medium, electronic equipment, the method comprises the following steps: based on the high-frequency conductivity of brain of brain's ultra-short echo sequence generation;Based on the diffusion microstructure parameter of brain of multi-shot diffusion weighted sequence acquisition;Based on the low-frequency conductivity tensor of the high-frequency conductivity and the diffusion microstructure parameter generation brain;Based on the high-frequency conductivity and the low-frequency conductivity tensor generation multi-frequency conductivity tensor;Based on the digital head model of magnetization preparation fast gradient echo sequence generation head;Based on the multi-frequency conductivity tensor and the digital head model generation brain frequency conductivity tensor model.The brain multi-frequency conductivity tensor modeling method, system, medium, electronic equipment of the application can accurately construct individualized brain multi-frequency conductivity tensor model, to provide support for tumor treatment field target planning and dose evaluation.

The present application belongs to the technical field of magnetic resonance imaging, and relates to a method for measuring remanence in a magnetic resonance imaging system by using double echo. In the method, gradient echo and spin echo are measured continuously after a test gradient is applied, the difference in the effect of magnetic field inhomogeneity on the two echoes is used to measure the change in magnetic field homogeneity before and after a high-intensity gradient magnetic field is applied, and the change in echo peak value caused by the change is used to measure the strength of remanence. The method of the present application does not require additional measuring instruments, the measuring process is simple and easy to implement, and the spatial anisotropy of remanence can be measured. The measuring method simultaneously obtains gradient echo and spin echo in one scan, simplifies the test process, and can avoid the difference in the initial state of the two echoes caused by the magnetic hysteresis effect, thereby reducing the measurement error. The method can evaluate the influence of remanence on spatial positioning in imaging, and is particularly suitable for judging whether a permanent magnetic resonance imaging system meets the requirements of monitoring and navigation on spatial positioning in interventional therapy.

A method for generating an image of a subject with a magnetic resonance imaging (MRI) system includes receiving MR image data acquired with the MRI system, where the MR image data includes first gradient echo data and second gradient echo data, and determining a linear phase error estimate. The linear phase error estimation may be based on all MR image data or a sub-volume thereof, and may include calculating a pixel phase error for each of a plurality of pixels within the MR image data and determining an average value of the pixel phase errors. The corrected MR image data is generated based on a linear phase error estimate, and then a water image and / or a fat image is generated based on the corrected MR image data.