51 results about "Radial sampling" patented technology

A probe with an integral filtered vent and sampling port has a hollow shaft configured as a drill bit which in use passes through the lid of a drum containing waste products within a liner. The hollow shaft has a penetrating tip and at lest two radial bores, one of which is positioned to open to the space within the liner and the other of which is positioned to open to the space above the liner and between the liner and drum lid. The shaft has a head with a pocket which contains a filter element, the head also having a radial sampling port with a septa seal. In order to sample head space gases, a hypodermic needle is pushed through the septa seal into the longitudinal bore of the hollow shaft, and then withdrawn, allowing the septa seal to close behind the needle. The probe is especially useful for sampling nuclear waste stored within drums having liners. This is because the probe has a first radial port adjacent the penetrating tip thereof which samples gas within the liner and a second radial port disposed between the liner and lid for sampling gas which has escaped past the liner.

Exemplary method, system and computer-accessible medium can be provided which facilitates an acquisition of radial data, which can be continuous, with an exemplary golden-angle procedure and reconstruction with arbitrary temporal resolution at arbitrary time points. According to such exemplary embodiment, such procedure can be performed with a combination of compressed sensing and parallel imaging to offer a significant improvement, for example in the reconstruction of highly undersampled data. It is also possible to provide an exemplary procedure for highly-accelerated dynamic magnetic resonance imaging using Golden-Angle radial sampling and multicoil compressed sensing reconstruction, called Golden-angle Radial Sparse Parallel MRI (GRASP).

In some embodiments, the present application discloses utilizing a continuous spoiled gradient echo sequence with 3D radial trajectory and 1D self-gating for respiratory motion detection. In certain embodiments, data acquired are retrospectively sorted into different respiratory phases based on their temporal locations within a respiratory cycle, and each phase is reconstructed via a self-calibrating CG-SENSE program.

In a magnetic resonance imaging method and apparatus, sensitivity encoding (SENSE) with radial sampling trajectories combines the gridding principle with conjugate-gradient least-squares (CGLS) iterative reconstruction. Radial k-space is mapped to a larger matrix by a resealing factor to eliminate the computational complexity of conventional gridding and density compensation. To improve convergence rate of high spatial frequency signals in CGLS iteration, a spatially invariant de-blurring k-space filter uses the impulse response of the system. This filter is incorporated into the SENSE reconstruction as preconditioning. The optimal number of iterations represents a tradeoff between image accuracy and noise over several reduction factors.

The invention discloses a fast and precise MRI (Magnetic Resonance Imaging) reconstruction method. The method comprises steps: scanning is carried out in a target visual field to obtain K space full sampling data; the K space full sampling data are sampled by using radial sampling to obtain under sampling data; the under sampling data are subjected to multi-loop data recovery to obtain an MRI image; and double-density dual-tree complex wavelet transform is used as a sparse basis, and according to the priori information of the MRI image under the double-density dual-tree complex wavelet transform, an FISTA algorithm is combined for image reconstruction. The reconstruction method can better depict image details and information, and the quality of the recovered image is improved.

The contrast of an image captured by imaging using a multi-echo sequence by radial sampling is improved.Images are simultaneously captured by using a multi-echo sequence by radial sampling, and echo signal groups of one or more blocks measured by executing the imaging using the multi-echo sequence are divided into a plurality of partial echo signal groups.Using the partial echo signal groups, images with different contrasts are reconstructed.

The invention discloses a method and device for processing radar echo sampling data. The method includes the following steps that when a frame of radar echo sampling data is received, according to the number of radial sampling points of the radar echo sampling data and the number of peripheral sampling points of the radar echo sampling data, bilinear interpolation is conducted in the radial direction and / or the circumference direction to supplement missing sampling points, and according to rounding errors, an interpolation threshold compensation method is provided. The device includes an interpolation threshold compensation module, an inhibition image flashing module and an echogram display module. By means of the method and the device, an effective solution is provided for image display leaking point compensation, image flickering and satellite map overlay positioning and other problems in digital echo display in the prior art, the speed is high and the implementation efficiency is high.

An exemplary system, method and computer-accessible medium can be provided for generating an image(s) of a tissue(s) that can include, for example, receiving magnetic resonance imaging information regarding the tissue(s) based on a golden-angle radial sampling procedure, sorting and synchronizing the MRI information into at least two dimensions, and generating the image(s) of the tissue(s) based on the sorted and synchronized information. The tissue(s) include cardiac tissue and respiratory-affected tissue. The MRI information can include a motion of the cardiac tissue and a motion of the respiratory tissue.

The invention discloses a myocardium T1 quantifying method. The method includes the steps that after electrocardiograph gating trigger delay, non-layer-selection inversion pulses are applied; real-time interlaced collection of at least two layers of images is carried out with a fast spoiled gradient echo low-angle shot sequence of a radial sampling trajectory, and the inversion recovery process of signals is captured; a sampling line in diastole is selected to serve as a K space center line; with the selected sampling line as the center, the sampling line is symmetrically selected to carry out image reconstruction according to the size of a reconstruction window; a T1 quantifying graph is fitted with restructured images. The invention further discloses a device based on the method. By means of the method and the device, multiple layers of T1 quantifying images can be collected in one time of breathholding, the whole heart can be covered in two or three times of breathholding, and thus time waste and patient discomfort caused by breathholding are reduced.

The invention provides an optimization-based measurement matrix imaging method. The method comprises the steps: 01) carrying out Fourier transform on a target image to obtain K-space data; 02) carrying out sampling on the K-space data through a sampling matrix to obtain sampled signals for transmission; 03) carrying out sparse transformation on the target image to enable a reconstructed signal to be K-sparse; 04) obtaining sparse coefficients through the sampled signals; and 05) carrying out processing on the sparse coefficients through a fast iteration threshold algorithm to obtain a reconstructed image, wherein the sampling matrix is obtained by carrying out superposition on a random radial sampling matrix and a similar circular ring sampling matrix, and is a variable-density radial similar circular ring matrix meeting non-coherence characteristics with the sparse matrix. The variable-density radial similar circular ring matrix in the method has high randomness and easily meets the non-coherence characteristics with the sparse matrix, so that an image recovery effect is good.

A system and method for evaluating subjects using MRI and a contrast agent that overcomes the low sensitivity nature of previous detection methods is provided by using a 3D golden-angle-based radial sampling approach. In one configuration, direct detection of metabolic H217O generated from mitochondrial respiration may be imaged. Radial encoding allows for the use of ultra-short echo-time to compensate for signal loss due to the short T2 relaxation time of 17O and other contrast agents. In addition, the golden-ratio-based sampling scheme has the flexibility of enabling various undersampling schemes and retrospective selection of temporal resolution for dynamic imaging. A 3D radial sampling scheme may also give rise to additional SNR gain by further shortening the echo-time.

The invention relates to a method for generating a variable resolution digital elevation model. The method comprises the following steps of: establishing an east-north-sky right-handed coordinate system according to a measured topographic region, establishing a new plane coordinate system X'O'Y' in an XOY plane by using a measurement station point as a center, and establishing a polar coordinate system by using the original point of the new plane coordinate system as a pole and the direction far away from the center of the measurement station point as a polar axis; acquiring a three-dimensional data discrete point of the measured topographic region under the east-north-sky right-handed coordinate system; determining an angle sampling range in the polar coordinate system according to the measured topographic region, setting angle sampling intervals, and calculating the quantity of elevation sampling points required in the angle range; determining a radial sampling range along each angle direction, determining radial sampling change rates and sampling intervals, and calculating the quantity of the elevation sampling points required in the radial direction; and acquiring polar coordinates of all the elevation sampling points within the angle sampling range and the radial sampling range, constructing an irregular triangulation network according to the data discrete point, and calculating through interpolation to obtain elevation values of all the elevation sampling points. The method can be widely applied to data storage and expression during topographic and geomorphic measurement.

The invention relates to a thermal simulation furnace with heating / cooling controllable structure and capable of sampling halfway, comprising a furnace shell, a furnace lining arranged in the furnace shell, a soaking screen arranged at the inner cavity of the furnace lining, a radial sampling device arranged at the opening on the top of the soaking screen, a heating element, a thermocouple, a cooling pipe, and a control device, wherein a plurality of soaking screen cooling paths distributed uniformly are arranged on the outer wall of the soaking screen to form the soaking screen with a cooling structure. The furnace provided by the invention comprises a furnace plug with a crossing sampling structure and the soaking screen with hollow flanges and the cooling paths, and is characterized in that the furnace can be used with a computer for numerical simulation production, the heating efficiency can be accurately controlled, the cooling efficiency can be accurately controlled, the adjusting range of the cooling speed is large, the furnace can be used in each period for sampling for test, the amount of sample is large, the temperature field in the furnace is not influenced, the uniformity of temperature in the furnace is good, and the surface of the workpiece and the internal temperature can be monitored when the temperature is raising and lowering.

The invention provides a magnetic resonance interventional imaging method and system based on low rank and sparse decomposition, and a medium, and the method comprises the steps of: 1, continuously collecting k space data in a golden angle radial sampling mode in an interventional process; 2, grouping the collected k space data; and 3, reconstructing a magnetic resonance intervention image by adopting a method based on low-rank and sparse decomposition and framelet transformation. According to the method, based on grouped k space collection and reconstruction, reconstruction can be carried out under the condition that little data is acquired, the time resolution is high, and the real-time performance is good.

The invention provides a motion signal extracting method and device for self-gating three-dimensional cardiac imaging, and relates to the technical field of three-dimensional cardiac imaging. The method includes the steps that according to the TureFISP sequence, cardiac cine imaging data are obtained by adopting a multi-echo three-dimensional radial mixed collecting mode; signal values of multiple points are obtained from radial sampling lines of all collecting layers in the cardiac cine imaging data, and average values of the signal values of the multiple points are determined to serve as navigation signals; the navigation signals are subjected to inverse Fourier transformation to be transformed into an image domain, and heartbeat and breathing motion mixed signals are obtained through weighting; the heartbeat and breathing motion mixed signals are filtered through a band-pass filter to obtain heartbeat signals and breath signals; according to the heartbeat signals and the breath signals, the cardiac cine imaging data are arrayed and synchronized again to generate three-dimensional cardiac images. The problem that in the prior art, the quality of the rebuilt cardiac cine images is affected as obtained motion signals are inaccurate is solved.

The invention discloses a heart magnetic resonance imaging method based on a multi-scale low-rank model, and provides a new method for heart magnetic resonance imaging researching. A radial sampling track is adopted to realize undersampling of heart K space data, and full heart data radial undersampling is realized, and thereafter magnetic resonance data acquisition speed is accelerated, and then scanning time of a magnetic resonance device is reduced. The minimization expression of the heart magnetic resonance data based on multi-scale low-rank decomposition is used to improve the precision of the magnetic resonance imaging. A convex optimization problem of a reconstructed image is solved by an alternating direction multiplier method, and a speed of magnetic resonance imaging reconstruction is improved, and therefore the texture of the result of the reconstructed image is clear, and the edge is smooth.

The invention relates to the technical field of magnetic resonance imaging, and discloses a magnetic resonance dynamic imaging method, a device and a readable medium. The magnetic resonance dynamic imaging method comprises the following steps: step 1: filling the K space with a sampling mode of subsection acquisition between different respiratory cycles after receiving a trigger signal, and sampling data in the K space with a sampling mode of golden angle radial sampling trajectory in each cardiac cycle, wherein the golden angle radial sampling trajectory is approximated by an uniform radial sampling trajectory with the number of projections meeting a Fibonacci number; step 2: reconstructing an image on the two dimensions including the projection of radial sampling and the cardiac cycle with a-f BLAST method. The method of the present invention adopts the special uniform radial sampling trajectory (with the number of projections being a Fibonacci number) to approximate the golden angleradial sampling trajectory, breaking the limit of the uniform radial sampling of circular offset as the sampling mode, and can be applied in the golden angle radial sampling trajectory commonly usedin the dynamic imaging.

The present invention obtains high-quality images even in a case of measurement with a radial sampling method. For this purpose, pre-measurement is performed to extract only a component different for each blade from among shift amounts from among echo signals, and a shift amount in k-space of an echo signal by the said component is reflected to a reconstruction process. In the pre-measurement, echo signals are obtained respectively by applying readout gradient magnetic field pulses that change the polarity to the positive and negative and that have the same pulse shape as readout gradient magnetic field pulses to be used in an image acquisition sequence. A shift amount is obtained for each axis of X, Y, and Z of an MRI apparatus as a variation amount of a phase difference between both the echo signals.

The invention discloses a dynamic magnetic resonance image reconstruction method based on improved robust tensor principal component analysis. Precision and speed of an existing dynamic magnetic resonance image reconstruction method need to be improved. The method comprises: using tensors for representing K space data obtained through radial sampling, using a tensor robust principal component analysis tool for constructing an image reconstruction model, and guaranteeing the space integrity of high-dimensional data; providing a new tensor nuclear norm to constrain a low-rank part, so that the overall low-rank constraint is improved while the low-rank processing efficiency is ensured; carrying out time-frequency transformation on the sparse part and then carrying out threshold processing toimprove the reconstruction precision; finally, using an iterative soft threshold shrinkage algorithm to solve the optimization problem of the algorithm, and the image reconstruction quality and the accelerated reconstruction efficiency can be effectively improved. According to the invention, a high-quality diagnosis part image can be reconstructed in a short time, and a clear image can still be obtained at an extremely low sampling rate.

In a method, magnetic resonance apparatus, and pulse optimization computer for determining a pulse sequence for radial sampling of k-space in magnetic resonance imaging, the amplitudes and the increases with respect to time of readout gradients and phase gradients for individual sections of k-space are determined depending on an orientation of the respective section in k-space and depending on global maximum values of the amplitudes and the increases of the gradients on the physical axes.

The invention discloses a three-echo balanced steady state free precession impulse sequence imaging method and relates to the field of magnetic resonance imaging. The method comprises the following steps of: step 1, three-echo balanced steady-state free precession sequence imaging data acquisition: acquiring three echoes with different TE time, namely a first echo, a second echo and a third echo,under the condition that repetition time is not changed; step 2, three-echo balanced steady-state free precession sequence image reconstruction; and step 3, K-space trajectory correction on the imagereconstruction in the step 2. According to the method, three three-dimensional images can be obtained after radial sampling of a plurality of TRs, tissue information which cannot be displayed by a traditional balanced steady-state free precession impulse sequence can be obtained by utilizing the images of the three echoes, the signal-to-noise ratio of the images can be increased, and quantitativemeasurement of tissue attenuation parameters can be obtained. Three-dimensional imaging of bones, tendons, lungs and various soft tissues is obtained through the method; and the method is suitable forattenuation correction of positron emission imaging.

The invention relates to a magnetic resonance signal acquisition method, a magnetic resonance imaging method, a magnetic resonance system and a computer readable storage medium. The magnetic resonancesignal acquisition method includes the following steps: generating an initial linear sampling line passing through a K-space origin; carrying out rotation around the origin multiple times based on the initial linear sampling line to obtain a K-space radial sampling trajectory; and acquiring magnetic resonance signals according to the K-space radial sampling trajectory. By ensuring that the rotating linear sampling line obtained by the (2*N)th rotation is orthogonal to the rotating linear sampling line obtained by the (2*N+1)th rotation and the rotating linear sampling line obtained by the first rotation is orthogonal to the initial linear sampling line, the acquired magnetic resonance signals have more motion representation characteristics and can represent the current real motion condition of the patient's body, and motion artifacts can be better suppressed.

The invention discloses a radial acquisition based double-nuclide synchronous magnetic resonance imaging method. The method comprises the following specific steps of setting an examination area, a sampling spectrum width, a sampling point number and a radial sampling number; according to the Nyquist sampling law and a magnetogyric ratio of nuclide 1 to nuclide 2, calculating applied readout gradient intensities Grlevel 1 and Grlevel 2; according to a radial filling mode for planning three-dimensional k space, applying four gradient pulses to each gradient channel in sequence, and setting the gradient intensity and the gradient pulse width of each gradient channel; and setting parameters of an f1 channel and an f2 channel, wherein the f1 channel is a radio frequency channel corresponding to the nuclide 1, and the f2 channel is a radio frequency channel corresponding to the nuclide 2. According to the method, the resolutions of reconstructed images of the two nuclides in three space directions are consistent, accurate registration of the images of the two nuclides can be realized, and the problems that in conventional imaging, the imaging time of different nuclides is not synchronous, and the resolution difference is relatively large are solved.

In a method and magnetic resonance (MR) apparatus for reducing artifacts in an image dataset reconstructed from MR raw data that were acquired by radial sampling using different coil elements, for each of at least some of the coil elements, exclusion information is determined that identify MR data from that coil element that are responsible for at least one artifact, by a comparison of a sensitivity map, which defines a spatial reception capability of that coil element, with at least one comparison dataset obtained from at least a portion of the MR data from that coil element. At least the MR data identified from the exclusion information are excluded from the reconstruction of the image dataset.