19 results about "Fast spin echo" patented technology

The invention provides a brain low-frequency conductivity tensor modeling method, a brain low-frequency conductivity tensor modeling system, a medium and electronic equipment. The method comprises the following steps: acquiring a phase image of a fast spin echo sequence of a brain; acquiring a high-frequency conductivity image of the brain based on the phase image; collecting a diffusion weighted amplitude image of the brain based on a multi-excitation diffusion weighted sequence; based on the diffusion weighted amplitude image, using a multi-interlayer model to obtain diffusion microstructure parameters of the brain; generating a low-frequency conductivity tensor image of the brain based on the high-frequency conductivity image and the diffusion microstructure parameters; generating a digital head model based on the brain magnetization preparation fast gradient echo sequence; and generating a craniocerebral low-frequency conductivity tensor model based on the low-frequency conductivity tensor image and the digital head model. According to the brain low-frequency conductivity tensor modeling method and system, the medium and the electronic equipment, more accurate target point planning is provided for the tTIS.

The invention relates to a magnetic resonance imaging electromagnetic parameter distribution scanning and calculation method, which comprises the following steps that a fast spin echo sequence I is adopted to scan a target body, parameters are (alpha1, TE0, TR0 and Bw1), alpha is a deflection angle, TE is echo time, TR repetition time and Bw receiving bandwidth; scanning a target body by adopting a fast spin echo sequence II, wherein parameters are (alpha2, TE0, TR0 and Bw1); scanning a target body by adopting a fast spin echo sequence III, wherein parameters are (alpha2, TE0, TR0 and Bw2); and scanning the homogeneous water model by adopting the fast spin echo sequences I, II and III. And under the condition that the magnetic vector precession meets the conditions that the amplitudes are comparable when the phases are the same and the phases are differentiable when the amplitudes are the same, each magnetic field and electric field parameter is calculated based on the homogeneous water model data. According to the invention, decoupling of the proton density and the sensitive field of the signal is realized, so that magnetic resonance weighted quantization imaging becomes possible.

Described herein are methods for imaging magnetic resonance imaging (MRI) agents containing nanoconstructs therein using diffusion weighted fast spin echo (FSE) or gradient and spin echo (GRASE) methods.

The invention discloses a single-coil multi-layer parallel magnetic resonance imaging method based on multiple excitation in a low field, and the method comprises the steps: achieving the multi-layer parallel excitation through a multi-band pulse, and carrying out the 0-pi phase modulation of the multi-band pulse; constructing a fast spin echo sequence of secondary phase modulation; performing imaging by using the fast spin echo sequence subjected to secondary phase modulation; and reconstruction is carried out through an odd-even echo classification method, and a scanning result graph is obtained. Aiming at the common problem of low signal to noise ratio of low-field magnetic resonance imaging in practical application, based on hardware characteristics of a single coil of low-field magnetic resonance equipment and actual requirements of repeated scanning, a series of SMS related technologies such as an FSE fast spin echo sequence, Hadamard pulse coding, multi-band pulse and secondary phase modulation are combined; and the signal-to-noise ratio of the low-field FSE sequence is effectively improved.

The present invention provides a method, system, medium, and electronic device for modeling a low-frequency conductivity tensor of the brain. The method includes the following steps: acquiring a phase image of a fast spin echo sequence of the brain; acquiring a high-frequency conductivity image of the brain based on the phase image; acquiring a diffusion-weighted amplitude image of the brain based on a multi-excitation diffusion-weighted sequence; acquiring diffusion microstructure parameters of the brain using a multi-layer model based on the diffusion-weighted amplitude image; generating a low-frequency conductivity tensor image of the brain based on the high-frequency conductivity image and the diffusion microstructure parameters; generating a digital skull model based on a magnetization-prepared fast gradient echo sequence of the brain; and generating a low-frequency conductivity tensor model of the brain based on the low-frequency conductivity tensor image and the digital skull model. The method, system, medium, and electronic device for modeling a low-frequency conductivity tensor of the brain of the present invention provide more accurate target planning for tTIS.

Some implementations relate to methods, systems, and computer-readable media for medical imaging. A method includes providing as input to the neural network, a first image and a second image, wherein the first image and the second image are reconstructed from a fast spin echo (FSE) magnetic resonance (MR) imaging sequence, determining, using the neural network, a dense displacement field based at least on the first image and the second image, obtaining, using the neural network, a transformed image based on the first image and the dense displacement field, wherein the transformed image is aligned with the second image, computing a registration loss value based on comparison of the transformed image and the second image, and adjusting one or more parameters of the neural network based on the registration loss value.

The application provides a small animal sciatic nerve magnetic resonance coil and an imaging method, and the method comprises the following steps: filling a high-concentration sugar syrup solution at the bottom of the magnetic resonance coil and performing constant temperature control; placing a small animal in a prone position in the high-concentration sugar syrup solution and discharging air in the gap between the lower limbs and below the abdomen of the small animal; after performing magnetic resonance positioning scanning to determine the main sequence scanning range, starting the main sequence scanning, suppressing the flow tissue signal through a pre-pulse combination, exciting the tissue by using a radio frequency pulse with preset parameters, acquiring echo signals by combining a fast spin echo technology and filling K space, and obtaining scanning original data; performing preprocessing on the scanning original data and accurate segmentation of the sciatic nerve and spinal nerve to obtain a segmentation result; and completing three-dimensional model reconstruction, optimization and multi-modal fusion visualization based on the segmentation result to obtain an image scanning result. The application is suitable for small animals, is accurate in imaging, can effectively suppress various kinds of artifacts, and can be widely applied to sciatic nerve imaging scenarios of small animals.

A non-localized efficiency shimming technique is used to generate radio frequency (RF) shimming values for imaging with a multi-channel transmit RF coil that minimizes subject-specific imperfections in the transmit magnetic field (B1+) and reduces or eliminates signal dropout in the acquired images, while keeping the coil working in an optimal mode with a high transmit efficiency. The non-localized efficiency shimming can be used for both small and large fields-of-view where a specific ROI does not need to be specified. The static non-localized efficiency shim is advantageous for turbo spin echo (TSE) imaging of smaller anatomical targets, whereas the dynamic non-localized efficiency shim is advantageous for larger fields-of-view, such as in human torsos.

Systems and methods for suppressing image artifacts in multi-shot magnetic resonance (MR) images are disclosed. The techniques described herein include initiating a pulse train for a segment of a multi-shot fast spin-echo imaging procedure by applying an excitation radio frequency (RF) pulse, and transmitting a plurality of RF refocusing pulses for the segment. Each refocusing pulse of the plurality of RF refocusing pulses may have a respective phase that increases by a predetermined phase offset with each successive refocusing pulse of the segment. The techniques include generating k-space data based on a respective plurality of echoes detected by the MR system in response to the plurality of RF refocusing pulses.

The application discloses an infant brain T2 weighted magnetic resonance imaging optimization method based on a fast spin echo sequence. First, T1, T2 and PD quantitative imaging of the infant brain from 0 to 24 months old is collected to obtain T1, T2 and PD values of the infant brain white matter and gray matter regions, and according to the relationship characteristics of the infant brain white matter T2 value and the gray matter T2 value, the infant is divided into different month groups. Then, based on the 3D T2 weighted imaging of the variable flip angle fast spin echo sequence, the signal intensity of the infant brain white matter and gray matter under different refocusing flip angle chains is calculated through an extended phase graph algorithm, and the best flip angle chain design scheme of each group is determined with the maximum white matter / gray matter contrast as the target. The application fills the blank of the infant brain T2 weighted imaging optimization, formulates the best flip angle chain optimization scheme of different month groups, and thus significantly improves the contrast of the infant brain T2 weighted imaging.

The invention relates to a magnetic resonance weighted imaging contrast quantification and relaxation time inversion method, and belongs to the technical field of magnetic resonance imaging. According to the method, human tissues are scanned through three groups of parameter differentiated fast spin echo sequences, interference factors such as equipment characteristics, proton density and deflection angles are eliminated by using parameter relevance among the sequences, a weighted weight is obtained through calculation of an amplitude image ratio, and finally accurate T1 and T2 relaxation values are obtained through inversion. The core innovation of the method lies in that quantification of weighted imaging is realized through scientific design of sequence parameters: ultra-long TR0 and ultra-short TE0 are adopted to construct a reference amplitude image, and an amplitude ratio and relaxation time are directly correlated through mathematical derivation in combination with a moderate comparison sequence of TR1 and TE1. According to the method, the subjective limitation of traditional weighted imaging is broken through, the image detail resolution is higher, the individual evaluation difference and the deviation between equipment can be effectively reduced, and a reliable quantitative basis is provided for early lesion detection, longitudinal curative effect tracking and group data comparison.

In a magnetic resonance imaging method, a first adjustment parameter is determined for presetting an initial contrast of a magnetic resonance image; a second adjustment parameter is determined for obtaining an optimized contrast of the magnetic resonance image and a specified data acquisition time of a blade artifact correction sequence; an optimized echo signal evolution curve is determined according to the first adjustment parameter and the second adjustment parameter; an actual variable flip angle train is calculated according to the optimized echo signal evolution curve; and the actual variable flip angle train is applied to a two-dimensional fast spin echo sequence, and the blade artifact correction sequence corresponding to the second adjustment parameter is used to acquire magnetic resonance signals and enable the magnetic resonance image to satisfy the optimized contrast.

The invention relates to the technical field of medical image diagnosis, in particular to a black blood T2 weighted fast spin echo imaging method and system under a free breathing condition. According to the black blood imaging method based on reverse dual inversion recovery (RDIR) and single excitation fast spin echo (SS-FSE), artificial intelligence assisted compressed sensing (ACS) is introduced to improve the reconstruction quality. The slice selective reversal pulse is moved forward to the previous cardiac cycle, so that myocardial signal loss is effectively reduced; scanning time can be remarkably shortened and motion artifacts can be reduced by adopting single excitation. And in combination with the ACS, a high-resolution T2 weighted black blood image can be obtained under high and under-sampling conditions, and the method is particularly suitable for edema evaluation of children under free breathing.

The present invention discloses a method and device for correcting geometric distortion of MRI images, which relates to the field of medical image processing, and includes the steps of: acquiring echo planar imaging diffusion weighted imaging and fast spin echo diffusion weighted imaging from a magnetic resonance imaging device; performing preprocessing on the echo planar imaging diffusion weighted imaging and the fast spin echo diffusion weighted imaging to obtain preprocessed images. Main technical solutions and effects: Since geometric distortion will directly affect the accurate presentation of anatomical structures and lesion areas in MRI images, the present invention can provide more real and accurate image data by effectively correcting the geometric distortion in the echo planar imaging diffusion weighted imaging images, thereby improving the diagnostic accuracy of doctors, helping doctors better judge the location, size and shape of lesions, and further formulating more reasonable treatment plans.

Embodiments of the present invention disclose a fast positive contrast magnetic resonance imaging method and apparatus based on variable flip angles. The method includes: performing two data acquisitions on the same slice of the same target to respectively obtain fast spin echo data without echo readout gradient offset as original acquisition data, and fast spin echo data with echo readout gradient offset as offset acquisition data; on the same slice of the same target, determining the target local magnetic field generated by the metal device in the target area based on the phase difference and sampling parameters between the original acquisition data and the offset acquisition data; calculating a target susceptibility matrix according to the target local magnetic field and a pre-constructed target optimization function to achieve positive contrast magnetic resonance imaging. Embodiments of the present invention implement image reconstruction of a local field map combined with a susceptibility map through a magnetic resonance image reconstruction method of sparse under-sampling and background field removal, and further implement imaging of a metal device with a large susceptibility.

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 for operating a magnetic resonance tomograph for spatially resolved spin resonance measurement of an object, in particular a living object, which is arranged in a static magnetic field B0, whereby an alignment of the object's spins and a longitudinal net magnetization Mz along the direction Z of the static magnetic field results, and wherein a transverse magnetization component Mxy is generated or changed, in particular by generating a spin flip from the Z direction by a desired flip angle, in particular by 90 degrees, by means of at least one high-frequency excitation pulse (1) in spin resonance, wherein spin echo signals from at least one desired volume element of the object are measured using a sequence of high-frequency pulses (4, 5, 7) and switched gradient magnetic fields (2, 3, 6).wherein the at least one volume element is determined by several gradient magnetic fields superimposed at least temporarily on the homogeneous magnetic field B0, wherein the sequence of high-frequency pulses comprises a first (4) and a second high-frequency rephasing pulse (5), in particular a first (4) and second high-frequency rephasing pulse (5) directly after the generation of a transverse magnetization component by means of a high-frequency excitation pulse (1), wherein from the second high-frequency rephasing pulse (5) onwards both a spin echo and a stimulated echo are generated, wherein in addition to a gradient magnetic field (6) in the frequency coding direction, which is switched on during the measurement acquisition to acquire a line of the raw data space, an additional gradient magnetic field (8) in the frequency coding direction is switched on, which generates echo signals or echo signal components newly generated by the high-frequency rephasing pulses (5, 7),in particular, those not attributable to a refocusing of the original spin echo after the first radio frequency rephasing pulse (4) and / or of the original stimulated echo after the second radio frequency rephasing pulse (5), are shifted out of the raw data space or raw data line acquired in a subsequent measurement, characterized in that, during an evolution time (Tau) between the first (4) and second radio frequency rephasing pulse (5), T2*-induced relaxation processes act on a transverse magnetization component present after the first radio frequency rephasing pulse (4), and a magnetization component present in the longitudinal direction after the first radio frequency rephasing pulse (4) remains unaffected, wherein the absolute time between the first (4) and second radio frequency rephasing pulse (5) is extended by the evolution time beyond the duration of an echo interval,which is present between subsequent equidistant high-frequency rephasing pulses (5, 7).

Disclosed herein is a method of imaging at least a part of a subject (318). The method comprises receiving (200) k-space data (122) acquired according to a fast spin echo magnetic resonance imaging protocol. The method further comprises reconstructing (202) an initial magnetic resonance image (124) from the k-space data. The method further comprises receiving (204) a free induction decay artifact image (128) in response to inputting the initial magnetic resonance image into an image processing neural network (126). The image processing neural network is configured for filtering free induction decay artifacts from fast spin echo magnetic resonance images. The method further comprises generating (206) a clinical magnetic resonance image (130), through a combination of at least a portion of the free induction decay artifact image and the initial magnetic resonance image. The method further comprises providing (208) the clinical magnetic resonance image.

A computer-implemented method for operating a magnetic resonance device for acquiring magnetic resonance data is provided. The method may include providing (e.g., determining) a three-dimensional, slab-selective turbo spin echo sequence having at least one echo train is used, each echo train comprising an excitation module with an excitation pulse preceding a readout module. The readout module may include multiple refocusing pulses and associated readout intervals. The excitation pulse may be at least partly implemented as a variable rate selective excitation pulse. The readout module may immediately succeed the excitation module.