46 results about "Spin 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.

Multi-echo radio frequency (“RF”) gradient based magnetic resonance imaging (“MRI”) is described. A gradient is established in the B1 RF field to enable B1-encoded pulse sequences, such as B1-encoded spin-echo pulse sequences. As a non-limiting example, the B1-field gradient can be established using a multi-echo frequency-modulated Rabi encoded echoes (“ME-FREE”) technique.

A time-efficient diffusion magnetic resonance imaging systems and methods are provided that can produce multiple diffusion-weighted images with different b-values in one repetition time, and / or multiple diffusion-weighted images with different diffusion times in one repetition time, both by utilizing a train of stimulated echoes. Each stimulated echo in the train of stimulated echoes is generated by a re-excitation radio-frequency (RE) pulse with a variable flip angle, following an initial 90° excitation RE pulse and a subsequent 90° restoration RE pulse.

The present invention relates to the field of magnetic resonance imaging, and particularly to a method and system for magnetic resonance imaging. The method includes: acquiring a spin echo sequence and a plurality of gradient echo sequences; performing fitting calculations based on the plurality of gradient echo sequences to obtain a fitting density quantitative map, a fitting longitudinal relaxation quantitative map, and a fitting quasi-transverse relaxation quantitative map; obtaining a gradient-weighted image based on the fitting density quantitative map, the fitting longitudinal relaxation quantitative map, and the fitting quasi-transverse relaxation quantitative map; obtaining a relaxation decay image based on the gradient-weighted image and the spin echo sequence; obtaining a transverse relaxation quantitative map based on the relaxation decay image; performing weighted summation based on the fitting density quantitative map, the fitting longitudinal relaxation quantitative map, the relaxation decay image, and the transverse relaxation quantitative map to obtain a magnetic resonance multi-parameter image. The present invention increases the types of multi-parameter maps, facilitating the rapid acquisition of multiple contrast images.

The invention discloses a method, system and equipment for determining the emulsification effect of a middle-phase microemulsion based on nuclear magnetic resonance, a medium and a product, and relates to the technical field of oil exploitation, and the method comprises the following steps: carrying out baseline correction, noise removal, normalization processing and Laplace inverse transformation on a spin echo intensity signal; obtaining an effective diffusion coefficient-effective transverse relaxation time combined distribution diagram, projecting the effective diffusion coefficient-effective transverse relaxation time combined distribution diagram in an effective diffusion coefficient direction, and solving by adopting a multi-peak Gaussian fitting model and a least square method according to the effective diffusion coefficients of different components to obtain an effective diffusion coefficient range; and integrating the effective diffusion coefficient-effective transverse relaxation time combined distribution diagram within the effective diffusion coefficient range so as to determine an effective transverse relaxation time distribution curve, obtaining a simulated oil peak area in a bicontinuous phase and a simulated oil peak area in an oil phase through integration, and calculating the emulsification effect of the middle-phase microemulsion. According to the method, the accuracy of calculating the emulsification effect of the to-be-detected middle-phase microemulsion can be improved.

Provided are a photon up-conversion film, a photon up-conversion body, a laminate, and an energy conversion device, which are capable of high-efficiency up-conversion, and methods of producing the same. The photon up-conversion film according to an embodiment of the present invention includes a color-forming portion containing at least: a sensitizing component capable of absorbing light in a first wavelength region λ1; and a light-emitting component capable of radiating light in a second wavelength region λ2 including wavelengths shorter than those of the first wavelength region λ1. A relaxation time of the photon up-conversion film measured by a spin-echo method through use of time-domain nuclear magnetic resonance (pulse NMR) at 298 K is less than 210 ms.

This disclosure provides a nuclear magnetic resonance (NMR) analysis method for establishing the chemical composition and condensed-state structure of fluorine-containing materials and its application. The method includes: placing fluorine-containing materials under different operating conditions in a single-sided NMR spectrometer; under a single-sided inhomogeneous magnetic field environment; presetting parameters for a spin echo pulse sequence; using the spin echo pulse sequence to excite fluorine and hydrogen nuclei in the fluorine-containing material to obtain coupled NMR signals of fluorine and hydrogen nuclei; determining echo peak data from the coupled NMR signals according to the preset parameters; processing the echo peak data according to the structural characteristics of the fluorine-containing material to obtain relaxation spectrum fingerprint data; performing data transformation on the relaxation spectrum fingerprint data to obtain transverse relaxation time data; and establishing a relaxation spectrum fingerprint database and a transverse relaxation time database of the coupling of fluorine and hydrogen nuclei in the fluorine-containing material based on the relaxation spectrum fingerprint data and transverse relaxation time data under different operating conditions.

The application discloses a kind of nuclear magnetic resonance spectrum peak position detection method, device and readable medium, by obtaining two-dimensional spectrum based on spin echo phase change spectrum, SEcho-Net neural network is constructed and trained, SEcho-Net neural network includes coding layer and decoding layer, coding layer includes indirect dimension down-sampling module and direct dimension down-sampling module, indirect dimension down-sampling module is used to compress two-dimensional spectrum based on spin echo phase change spectrum, and first feature vector is obtained, first feature vector is input in direct dimension down-sampling module and extracts key information related to spectrum peak position, and obtains key feature, and decoding layer includes direct dimension up-sampling module and step-by-step dimension reduction module, direct dimension up-sampling module is used to recover spectrum information from key feature, and second feature vector is obtained, and second feature vector is input in step-by-step dimension reduction module and carries out feature extraction, and obtains spectrum peak pure chemical shift position information.The method has low experimental requirements, and can accurately locate spectrum peak position.

Preventing blood flow artifacts from being increased in an imaging plane allows reduction of the blood flow artifacts in the cross section subsequently excited. In the imaging using a spin-echo (SE) pulse sequence, an excitation width of a 90° pulse is extended from an imaging plane to one side. This one side indicates a downstream side of the blood flow with respect to a vessel of interest. In imaging multiple slices, the order of measuring the multiple imaging slices is set along the direction in which the width is extended.

A magnetic resonance (MR) imaging system includes a main magnet configured to generate a magnetic field, gradients coils configured to generate time varying gradient magnetic fields, a radiofrequency (RF) transmit coil configured to generate RF signals, a controller configured to control the gradient and RF transmit coil based on a first sequence that includes a pulse gradient spin echo (PGSE) acquisition and an oscillating gradient spin echo (OGSE) acquisition, an RF receive coil configured to receive first MR signals generated in response to the PGSE and OGSE acquisitions, an image reconstructor configured to process the first MR signals and generate a first apparent diffusion coefficient (ADC) map for the PGSE acquisition and a second ADC map for the OGSE acquisition, and a processor configured to generate a seed point map based on the first and second ADC maps, wherein the seed point map visually distinguishes tumor and vasogenic edema.

The invention relates to the field of geophysical exploration, in particular to a nuclear magnetic logging data inversion system and method based on semi-supervised adversarial learning. Comprising a T2 spectrum reconstructor which is used for training by adopting a label logging data set to obtain a nonlinear mapping relation between a spin echo signal and a preliminary T2 spectrum, and processing a non-label logging data set according to the nonlinear mapping relation to generate a predicted T2 spectrum; the false label selector generates the confidence coefficient of the predicted T2 spectrum according to a false matching data set obtained by matching the actual spin echo signal with the predicted T2 spectrum and a labeled logging data set, and selects the predicted T2 spectrum as a false label according to the confidence coefficient; mixing a pseudo label and a predicted T2 spectrum, and taking the mixture, a label logging data set and a non-label logging data set as a training set of a T2 spectrum reconstructor; and the T2 spectrum reconstructor is trained by the training set to obtain a nonlinear mapping relation between the actual spin echo signal and the predicted T2 spectrum. According to the invention, high-precision and high-efficiency intelligent nuclear magnetic logging data T2 spectrum inversion under a limited label condition is realized.

The present invention provides a magnetic resonance imaging apparatus and a control method thereof. Even when parallel imaging is employed for imaging using a spin-echo pulse sequence, artifacts caused by FID signals are suppressed. When executing a spin-echo pulse sequence using an excitation RF pulse to excite nuclear spins and an inversion RF pulse to invert the excited nuclear spins as high-frequency magnetic field pulses, the high-frequency transmitting unit of the MRI apparatus changes the phase of the inversion RF pulse according to the phase encoding and the number of phase encodings assigned to each echo signal. Specifically, the phase of the inversion RF pulse is controlled to be a quadratic function of the phase encoding of the echo signal.

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.

Provided are a photonic up-conversion film, a photonic up-conversion body, a laminate, and an energy conversion device capable of high-efficiency up-conversion, and a method for manufacturing the same. The photonic up-conversion film of an embodiment of the present application has a color development portion that contains at least a sensitizing component capable of absorbing light in a first wavelength range λ1 and a luminescent component capable of emitting light in a second wavelength range λ2 shorter in wavelength than the first wavelength range λ1. With respect to the photonic up-conversion film, the relaxation time measured by the spin echo method using the time-domain nuclear magnetic resonance method (pulse NMR) at 298 K is less than 210 ms.

Disclosed in the present invention are a 3D navigator-based 3D gradient spin-echo diffusion imaging method, and a device. The method comprises: first, using a global saturation module to destroy previous residual transverse magnetization; second, by means of a diffusion encoding module, embedding a pair of trapezoidal cosine oscillation gradients or pulse gradients into radio frequency pulses of 90°x-180°y-90°-x, and separating diffusion encoding from signal acquisition; then using a fat saturation module to suppress a fat signal; using a 3D gradient spin-echo readout method to acquire an image signal; and finally, acquiring a 3D navigation echo signal in the last spin echo for correcting a phase error between multiple excitations. The present invention can effectively eliminate phase errors between multiple acquisitions and realize high-resolution whole-brain diffusion imaging. Compared with 2D echo planar imaging, the present invention increases the signal-to-noise ratio of diffusion magnetic resonance imaging, thereby supporting higher-resolution whole-brain 3D diffusion magnetic resonance imaging.

The invention relates to a radio frequency pulse flip angle determination method and device and computer equipment. And according to the actual scanning parameter and the signal amplitude function of the magnetic resonance scanning sequence, determining the candidate signal amplitude of each candidate flip angle corresponding to the radio frequency pulse under the actual scanning parameter, and according to the candidate signal amplitude of each candidate flip angle, determining a target flip angle corresponding to the radio frequency pulse. In the embodiment of the invention, the candidate signal amplitudes of the plurality of candidate flip angles under the actual scanning parameter are determined through the signal amplitude function, and the target flip angle of the radio frequency pulse under the actual scanning parameter is determined according to the plurality of candidate signal amplitudes, so that the flip angle of the radio frequency pulse in the spin echo sequence is optimized, the longitudinal magnetization vector is recovered more quickly, and the accuracy of the spin echo sequence is improved. Therefore, the signal amplitude generated by excitation each time is improved, and the signal-to-noise ratio of a magnetic resonance image is finally improved.

Single-sided MRI apparatuses, systems, and methods are disclosed. A method can include transmitting a frequency sweep excitation pulse comprising a low-to-high frequency sweep; phase encoding during the frequency sweep excitation pulse; and tuning the amount of phase accumulated during the frequency sweep excitation pulse from adjacent slices in the slab. The frequency sweep excitation pulse can be a chirp pulse. Encoding in this way can prevent spin echoes from drifting and prevent k-space truncation in certain instances. Moreover, the resultant images can be combined more efficiently.

Provided are a photon up-conversion film, a photon up-conversion body, a laminate, and an energy conversion device which are capable of highly efficient up-conversion, and methods for producing the same. A photon up-conversion film according to an embodiment of the present invention is provided with a color-developing section that contains at least a sensitizing component capable of absorbing light in a first wavelength range [lambda] 1 and a light-emitting component capable of emitting light in a second wavelength range [lambda] 2 having a shorter wavelength than the first wavelength range [lambda] 1. The relaxation time of the photon up-conversion film as measured by a spin-echo method using a time-domain nuclear magnetic resonance method (pulsed NMR) at 298 K is less than 210 ms.

Systems and methods of detecting a portion within tissue that has a variation of local magnetic susceptibility using an MRI device, including: transmitting a first spin-echo pulse sequence to the tissue, wherein the first spin-echo pulse sequence includes a first number of refocus pulses and a first TE value; transmitting a second spin-echo pulse sequence to the tissue, wherein the second spin-echo pulse sequence includes a second number of refocus pulses and a second TE value; obtaining a first image and a second image; determining one or more locations within the second image having a signal intensity that is different than the signal intensity of the same one or more locations within the first image; and identifying a portion of tissue that has a varied local magnetic susceptibility based on the determined one or more locations within the second image.

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 magnetic resonance (MR) imaging system includes a main magnet configured to generate a magnetic field, gradients coils configured to generate time varying gradient magnetic fields, a radiofrequency (RF) transmit coil configured to generate RF signals, a controller configured to control the gradient and RF transmit coil based on a first sequence that includes a pulse gradient spin echo (PGSE) acquisition and an oscillating gradient spin echo (OGSE) acquisition, an RF receive coil configured to receive first MR signals generated in response to the PGSE and OGSE acquisitions, an image reconstructor configured to process the first MR signals and generate a first apparent diffusion coefficient (ADC) map for the PGSE acquisition and a second ADC map for the OGSE acquisition, and a processor configured to generate a seed point map based on the first and second ADC maps, wherein the seed point map visually distinguishes tumor and vasogenic edema.

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.

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.

This invention provides a method, system, medium, and electronic device for locating epileptic lesions. The method includes the following steps: reconstructing a non-magnetic perturbation transverse relaxation rate (R2) image based on multi-echo spin echo data from the brain; constructing a paramagnetic brain iron image based on the multi-echo gradient echo data from the brain, the non-magnetic perturbation transverse relaxation rate (R2) image, and an amplitude attenuation kernel; updating the amplitude attenuation kernel based on the paramagnetic brain iron image; updating the paramagnetic brain iron image based on the updated amplitude attenuation kernel until both the paramagnetic brain iron image and the amplitude attenuation kernel converge; and locating the epileptic lesion based on the converged paramagnetic brain iron image. The epileptic lesion localization method, system, medium, and electronic device of this invention achieves epileptic lesion localization based on paramagnetic brain iron images, effectively improving localization accuracy and efficiency.

To provide single-sided MRI apparatuses, systems and methods.SOLUTION: A method includes: transmitting a frequency sweep excitation pulse comprising a low-to-high frequency sweep; phase-encoding during the frequency sweep excitation pulse; and tuning the amount of phase accumulated during the frequency sweep excitation pulse from adjacent slices in a slab. The frequency sweep excitation pulse can be a chirp pulse. Encoding in this way can prevent spin echoes from drifting and prevent k-space truncation in certain instances. Moreover, the resultant images can be combined more efficiently.SELECTED DRAWING: Figure 13

Magnetic resonance imaging (“MRI”) using a spin- and gradient-echo (“SAGE”) pulse sequence with blip up-down acquisition (“BUDA”) encoding enables distortion-free, high-resolution diffusion-weighted imaging and / or quantitative parameter mapping. Phase-encoding polarities are alternated across shots during a multi-shot acquisition. In each shot, multi-contrast data are acquired at echo times associated with a gradient echo, a mixed gradient-and-spin echo, and a spin echo. High in-plane resolution and distortion-free quantitative parameter maps can be generated, such as T2 maps. T2* maps, paramagnetic susceptibility maps, and diamagnetic susceptibility maps. Diffusion-weighted data can be acquired using diffusion encoding gradients and BUDA encoding, where multi-contrast data are acquired in the b=0 acquisition. Diffusion parameter maps can be generated from the b=0 and diffusion-weighted data.

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 method for MR imaging of an object (10) positioned in an examination volume of an MR device (1). The object of the invention is to achieve fast spiral MR imaging with a defined T2 contrast. The method of the invention comprises the following steps: generating a plurality of spin echoes by subjecting the object (10) to one or more shots of an imaging sequence, each shot comprising an RF excitation pulse (21) followed by a plurality of RF refocusing pulses (22), wherein a modulated readout magnetic field gradient (23, 24) is applied in each interval between consecutive RF refocusing pulses (22); acquiring MR signal data, wherein each spin echo is recorded in k-space along a spiral trajectory (31-33, 41-43) winding around a k-space origin at a continuously varying radial distance, wherein the trajectory (31, 41) of at least one spin echo has a different rate of change of the radial distance than the trajectories (32, 33, 42, 43) of the other spin echoes, at least in a central k-space region; and reconstructing an MR image based on the acquired MR signal data. The invention also relates to an MR device (1) and a computer program for an MR device (1).

The invention provides a magneto-optical pulse regulation and control-based SERF (single-electron radio frequency) gyroscope coupling spinning rapid overturning method, relates to the technical field of inertial navigation and quantum precision measurement, and adopts the magneto-optical pulse regulation and control-based SERF gyroscope coupling spinning rapid overturning method. Through cooperative control of rapid switching of a pi pulsed magnetic field and pumping light polarization driven by an electro-optical modulator (EOM) in the SERF atomic spin gyroscope, efficient and rapid overturning of a coupling spin system composed of alkali metal electron spin and inert gas nuclear spin in a self-compensation working state is realized. The method is suitable for periodic control of coupling spin polarization in a high-precision atomic spin gyroscope and suppression of system low-frequency drift errors.