30 results about "Magnetic resonance spectroscopic imaging" patented technology

A method of magnetic resonance spectroscopic imaging of an object (O) including at least one chemical species to be imaged, comprising sampling of the k-space such that a plurality of Nω first sampling trajectories through at least one k-space segment of the k-space is formed along a phase-encoding direction, each of said first sampling trajectories beginning in a central k-space region and continuing to a k-space border of the at least one k-space segment and having a duration equal to or below a spectral dwell time corresponding to the reciprocal spectral bandwidth, collecting at least one first set of gradient-echo signals obtained along said first sampling trajectories, collecting at least one second set of gradient-echo signals obtained along a plurality of Nω second sampling trajectories, said Nω second sampling trajectories and said Nω first sampling trajectories being mutually mirrored relative to a predetermined k-space line in the central k-space region.

A method and apparatus for enhancing the spectral resolution of magnetic resonance spectroscopic (MRS) measurements include receiving time domain echo data from an MRS measurement for an MRS volume in a subject. Also received are high spatial resolution complex signal values within the MRS volume based on magnetic resonance imaging (MRI) measurements. Frequency-domain content is determined for the echo data based at least in part on the complex signal values. For example, in some embodiments, receiving complex signal values includes receiving high spatial resolution complex signal values within the MRS volume for each of two different echo time settings. The frequency-domain content of the echo data is corrected for a lineshape profile based on high resolution frequency dispersion values for the MRS volume determined from differences in the complex signal values for the two different echo time settings.

A method for designing non-linear phase 180° spectral-spatial radio frequency pulses that can be used for spectral editing in magnetic resonance spectroscopic imaging. A novel feature of the pulse is a symmetric sweep developed by the spectral profile from the outside edges of the spectral window towards the middle whereby coupled components are tipped simultaneously and over a short interval. Pulses have been designed for lactate editing at 1.5T and 3T. The spectral and spatial spin-echo profiles of the RF pulses can be measured experimentally and altered in an iterative manner. Spectral-spatial radio frequency (SSRF) pulses allow simultaneous selection in both frequency and spatial domains. These pulses are particularly important for clinical and research magnetic resonance spectroscopy (MRS) applications for suppression of large water and lipid resonances.

The present invention relates to a magnetic resonance spectroscopic imaging (MRSI) method, specifically to a magnetic resonance spectroscopic imaging method with up to three spatial dimensions and one spectral dimension. Interleaving dynamically switched magnetic field gradients into the spectroscopic encoding scheme enables multi-region shimming in a single shot to compensate the spatially varying spectral line broadening resulting from local magnetic field gradients. The method also employs sparse spectral sampling with controlled spectral aliasing and nonlinear sampling density to maximize encoding speed, data sampling efficiency and sensitivity.

The present invention relates to a magnetic resonance spectroscopic imaging (MRSI) method, specifically to a magnetic resonance spectroscopic imaging method with up to three spatial dimensions and one spectral dimension. Interleaving dynamically switched magnetic field gradients into the spectroscopic encoding scheme enables multi-region shimming in a single shot to compensate the spatially varying spectral line broadening resulting from local magnetic field gradients. The method also employs sparse spectral sampling with controlled spectral aliasing and nonlinear sampling density to maximize encoding speed, data sampling efficiency and sensitivity.

A method for increasing sensitivity and / or specificity of a magnetic resonance spectroscopy imaging technique for detecting a neurodegenerative disease is provided. The method includes acquiring magnetic resonance spectroscopy data from the brain of a subject, while suppressing certain metabolites in the spectrum via a data acquisition protocol, to improve quantification accuracy for the remaining metabolites, and quantifying a metabolite concentration or a metabolite concentration ratio from the spectral data as an indicator of the neurodegenerative disease.

This invention relates to localized magnetic resonance spectroscopy (MRS) and to magnetic resonance spectroscopic imaging (MRSI) of the proton NMR signal, specifically to a magnetic resonance spectroscopy (MRS) method to measure a single volume of interest and to a magnetic resonance spectroscopic imaging method with at least one spectral dimension and up to three spatial dimensions. MRS and MRSI are sensitive to movement of the object to be imaged and to frequency drifts during the scan that may arise from scanner instability, field drift, respiration, and shim coil heating due to gradient switching. Inter-scan and intra-scan movement leads to line broadening and changes in spectral pattern secondary to changes in partial volume effects in localized MRS. In MRSI movement leads to ghosting artifacts across the entire spectroscopic image. For both MRS an MRSI movement changes the magnetic field inhomogeneity, which requires dynamic reshimming. Frequency drifts in MRS and MRSI degrade water suppression, prevent coherent signal averaging over the time course of the scan and interfere with gradient encoding, thus leading to a loss in localization. It is desirable to measure object movement and frequency drift and to correct object motion and frequency drift without interfering with the MRS and MRSI data acquisition.

The invention provides a breast tumor diagnosis system based on magnetic resonance spectrum imaging, comprising a superconduction MR (Magneto Resistance) scanner and a computer system. Through a computer auxiliary detection measure, the breast tumor diagnosis system realizes the early identification diagnosis of a breast tumor and the further diagnosis of breast cancer. Mammary gland magnetic resonance spectrum data are studied by adopting a distinctive manifold study method and projected to a low dimension embedding space, thus not only a low dimension manifold structure hidden in a high dimension magnetic resonance spectrum space can be revealed, but also the identification information in the mammary gland magnetic resonance spectrum data can be efficiently kept; then optimization clustering is carried out on the low dimension identification characteristic by utilizing a clustering method so that data points without the similar identification characteristic are separated to the maximum; and further a cost sensitive mechanism is introduced to achieve misclassification total cost minimization and realize optimization diagnosis of the breast cancer.

A new method is developed to accelerate high-resolution magnetic resonance spectroscopic imaging (MRSI). The method is built on a low-dimensional subspace model exploiting the partial separability of high-dimensional MRSI signals and uses this subspace model for data acquisition, processing, and image reconstruction. Specifically for two and three dimensional MRSI with one spectral dimension, this method sparsely samples the corresponding (k,t)-space in two complementary data sets, one with dense temporal sampling and high signal-to-noise ratio but limited k-space coverage and the other with sparse temporal sampling but extended k-space coverage. The reconstruction is then done by estimating a set of temporal / spectral basis functions and the corresponding spatial coefficients from these two data sets. The proposed subspace model can be further extended to incorporate multiple signal components for nuisance signal removal in 1H-MRSI and more generalized reconstruction methods. The resulting imaging technique can be used for high-resolution MRSI of different nuclei. It will be useful for high-resolution metabolic imaging with many exciting applications.

A method of magnetic resonance spectroscopic imaging of an object (O) including at least one chemical species to be imaged, comprising sampling of the k-space such that a plurality of Nω first sampling trajectories through at least one k-space segment of the k-space is formed along a phase-encoding direction, each of said first sampling trajectories beginning in a central k-space region and continuing to a k-space border of the at least one k-space segment and having a duration equal to or below a spectral dwell time corresponding to the reciprocal spectral bandwidth, collecting at least one first set of gradient-echo signals obtained along the first sampling trajectories, collecting at least one second set of gradient-echo signals obtained along a plurality of Nω second sampling trajectories, the Nω second sampling trajectories and the Nω first sampling trajectories being mutually mirrored relative to a predetermined k-space line in the central k-space region.

A method of performing spatially localized magnetic resonance spectroscopy includes receiving a magnetic resonance image of an object; identifying a plurality C of compartments that generate magnetic resonance spectroscopy signals in the object including at least one compartment of interest; segmenting in at least one spatial dimension the magnetic resonance image of the object into the C compartments; acquiring magnetic resonance spectroscopy signals from the compartments by applying a plurality of M′ phase encodings applied in the at least one spatial dimension, wherein M′≧C; calculating a spatially localized magnetic resonance chemical shift spectrum from the at least one compartment of interest; and rendering a spatially localized magnetic resonance spectrum that is substantially equal to a spatial average of magnetic resonance chemical shift spectra from the at least one compartment of interest. A magnetic resonance spectroscopy and imaging system is configured to perform the above method.

A system, method and software arrangement according to exemplary embodiments of the present invention are provided which can use molecular profiles obtained from unaltered human tissue specimens for clinical purposes including disease diagnoses and treatment evaluations. For example, spatial distributions of chemical species including metabolites within the tissue may be obtained using radiological techniques such as magnetic resonance spectroscopy imaging. Disease-specific profiles may be obtained by comparing the distributions of chemical species obtained in ex vivo tissues with pathological observations made on them using statistical analysis. The disease-specific profiles may then be correlated with in vivo or ex vivo molecular profiles to obtain spatial maps that can provide a more sensitive and accurate detection of diseased tissue. Thus, such exemplary systems, methods and software arrangements can include the ability to receive information relating to the distribution of at least three chemical species in the tissue of interest, compare this information statistically to a predetermined profile and, based on the statistical correlation between the information and the profile, determine certain characteristics of the tissue of interest such as, e.g., the presence or absence of diseased tissue.

A method for designing non-linear phase 180° spectral-spatial radio frequency pulses that can be used for spectral editing in magnetic resonance spectroscopic imaging. A novel feature of the pulse is a symmetric sweep developed by the spectral profile from the outside edges of the spectral window towards the middle whereby coupled components are tipped simultaneously and over a short interval. Pulses have been designed for lactate editing at 1.5 T and 3 T. The spectral and spatial spin-echo profiles of the RF pulses can be measured experimentally and altered in an iterative manner. Spectral-spatial radio frequency (SSRF) pulses allow simultaneous selection in both frequency and spatial domains. These pulses are particularly important for clinical and research magnetic resonance spectroscopy (MRS) applications for suppression of large water and lipid resonances.

A method and apparatus for enhancing the spectral resolution of magnetic resonance spectroscopic (MRS) measurements include receiving time domain echo data from an MRS measurement for an MRS volume in a subject. Also received are high spatial resolution complex signal values within the MRS volume based on magnetic resonance imaging (MRI) measurements. Frequency-domain content is determined for the echo data based at least in part on the complex signal values. For example, in some embodiments, receiving complex signal values includes receiving high spatial resolution complex signal values within the MRS volume for each of two different echo time settings. The frequency-domain content of the echo data is corrected for a lineshape profile based on high resolution frequency dispersion values for the MRS volume determined from differences in the complex signal values for the two different echo time settings.

The invention belonging to the field of medical imaging provides a frequency-domain-based method for lipid and water suppression treatment of magnetic resonance spectrum imaging data. The method comprises: one-dimensional Fourier transform is carried out on collected single voxel magnetic resonance spectrum time-domain data to obtain a frequency-domain FID signal; according to prior knowledge, four lipid peaks and one water signal frequency range are determined; a nonlinear parameter attenuation coefficient in a spectrum time-domain model by using a singular value decomposition method; on the basis of a spectrum peak frequency in the prior knowledge and the attenuation coefficient obtained by quantification, the amplitude and phase of a linear parameter are estimated by using an amplitude-phase adaptive FIR filtering method; the frequency range is changed and the previous two steps are executed circularly until quantification of the four group of lipid and water signal parameters is completed; the time-domain FID model and the lipid and water signal quantification parameters form lipid and water time-domain signals; and one-dimensional Fourier transform is carried out on the time-domain signals, difference processing is carried out on the frequency domain and an original spectral signal, thereby obtaining magnetic resonance spectrum imaging data after lipid and water suppression treatment.

An exemplary embodiment of system, method, and computer accessible medium for magnetic resonance spectroscopic imaging for improving signal-to-noise ratio per unit time and optimizing duty cycle in MRSI and / or for reducing chemical-shift artifacts can be provided. One exemplary embodiment includes forwarding an excitation pulse to the target and acquiring a signal from the target by multiplexing in time and space. Multiplexing in time may involve segmenting a field of view of the at least one portion of the target into a predetermined number of slabs that are acquired sequentially during each repetition time. Multiplexing in space may involve acquiring multiple voxels. Data may be generated based on the acquired signal. A further exemplary embodiment includes providing an excitation pulse to the target and acquiring a signal from the target. The excitation pulse can be a series of cascaded Hadamard pulse components. Data may be generated based on the acquires signal.

Various embodiments accelerate high-resolution magnetic resonance spectroscopic imaging (MRSI). Various embodiments are built on a low-dimensional subspace model exploiting the partial separability of high-dimensional MRSI signals. For two and three dimensional MRSI with one spectral dimension, various embodiments sparsely sample the corresponding (k,t)-space in two complementary data sets, one with dense temporal sampling and high signal-to-noise ratio but limited k-space coverage and the other with sparse temporal sampling but extended k-space coverage. The reconstruction is then done by estimating a set of temporal / spectral basis functions and the corresponding spatial coefficients from these two data sets. The imaging technique of various embodiments can be used for high-resolution MRSI of different nuclei.

A method and system for providing a fast image reconstruction of magnetic resonance spectroscopic imaging (MRSI) data based on applying, at least in part, interferometric techniques using a single receiver element. The images are reconstructed through temporally cross-correlating spacially incoherent k-space locations.

A method for increasing sensitivity and / or specificity of a magnetic resonance spectroscopy imaging technique for detecting a neurodegenerative disease is provided. The method includes acquiring magnetic resonance spectroscopy data from the brain of a subject, while suppressing certain metabolites in the spectrum via a data acquisition protocol, to improve quantification accuracy for the remaining metabolites, and quantifying a metabolite concentration or a metabolite concentration ratio from the spectral data as an indicator of the neurodegenerative disease.

A new method is developed for ultrafast, high-resolution magnetic resonance spectroscopic imaging (MRSI) using learned spectral features. The method uses Free Induction Decay (FID) based ultrashort-TE and short-TR acquisition without any solvent suppression pulses to generate the desired spatiospectral encodings. The spectral features for the desired molecules are learned from specifically designed “training” data by taking into account the resonance structure of each compound generated by quantum mechanical simulations. A union-of-subspaces model that incorporates the learned spectral features is used to effectively separate the unsuppressed water / lipid signals, the metabolite signals, and the macromolecule signals. The unsuppressed water spectroscopic signals in the data can be used for various purposes, e.g., removing the need of additional auxiliary scans for calibration, and for generating high quality quantitative tissue susceptiability mapping etc. Simultaneous spatiospectral reconstructions of water, lipids, metabolite and macromolecule can be obtained using a single 1H-MRSI scan.

The invention provides a breast tumor diagnosis system based on magnetic resonance spectrum imaging, comprising a superconduction MR (Magneto Resistance) scanner and a computer system. Through a computer auxiliary detection measure, the breast tumor diagnosis system realizes the early identification diagnosis of a breast tumor and the further diagnosis of breast cancer. Mammary gland magnetic resonance spectrum data are studied by adopting a distinctive manifold study method and projected to a low dimension embedding space, thus not only a low dimension manifold structure hidden in a high dimension magnetic resonance spectrum space can be revealed, but also the identification information in the mammary gland magnetic resonance spectrum data can be efficiently kept; then optimization clustering is carried out on the low dimension identification characteristic by utilizing a clustering method so that data points without the similar identification characteristic are separated to the maximum; and further a cost sensitive mechanism is introduced to achieve misclassification total cost minimization and realize optimization diagnosis of the breast cancer.

A method of performing spatially localized magnetic resonance spectroscopy includes receiving a magnetic resonance image of an object; identifying a plurality C of compartments that generate magnetic resonance spectroscopy signals in the object including at least one compartment of interest; segmenting in at least one spatial dimension the magnetic resonance image of the object into the C compartments; acquiring magnetic resonance spectroscopy signals from the compartments by applying a plurality of M′ phase encodings applied in the at least one spatial dimension, wherein M′≥C; calculating a spatially localized magnetic resonance chemical shift spectrum from the at least one compartment of interest; and rendering a spatially localized magnetic resonance spectrum that is substantially equal to a spatial average of magnetic resonance chemical shift spectra from the at least one compartment of interest. A magnetic resonance spectroscopy and imaging system is configured to perform the above method.

The invention discloses a method for suppressing water signals and enhancing metabolite signals by adjusting the central frequency and receiving bandwidth of excitation signal frequency bands in magnetic resonance spectroscopy (MRS) imaging technology. According to an embodiment of the water signal suppression and metabolite signal enhancement method, an excitation signal adjusted to have a center frequency lower than the resonance frequency of water is applied, and the size of the receiving bandwidth is adjusted to match the resonance frequency of the water and the resonance frequency of the water. The center frequency difference is the same.

A method for the compensation of magnetic field inhomogeneity in magnetic resonance spectroscopic imaging comprising the steps of using dynamic k-space expansion in combination with parallel imaging.

The invention discloses a fat pressing method for magnetic resonance spectrum imaging. The fat pressing method comprises the following steps of: acquiring non-fat-pressing spectrum imaging data: acquiring the non-fat-pressing spectrum imaging data by adopting a CSI (Channel State Information) sequence; preprocessing the data: preprocessing the non-fat-pressing wave spectrum imaging data to obtain data XCSI; preparing masks: preparing a lipid signal mask MIipid and a metabolite signal mask Mtrain; performing double-weight signal reconstruction to obtain a double-weight signal Xdual; and performing L2 constraint reconstruction to obtain metabolite spectrum signals X with lipid signals removed. The data acquisition sequence adopted by the method is a clinical common sequence and does not need to be acquired for multiple times, so that the data acquisition time is short; lots of prior information is not needed; and lipid signals can be quickly and robustly removed, and metabolite signals can be retained.

The invention relates to a magnetic resonance spectrum imaging method and device, computer equipment and a storage medium. The method comprises the steps of scanning for multiple times by adopting a preset scanning sequence, wherein the preset scanning sequence comprises an excitation pulse and a spatial positioning coding gradient, the excitation pulse comprises three mutually perpendicular layer selection pulses, and the three mutually perpendicular layer selection pulses are matched with the corresponding spatial positioning gradients to determine voxels of interest; acquiring a response signal of each scanning, and setting the acquisition times of each filling position in the K space according to a preset weight; filling the response signals acquired for multiple times into corresponding positions of the K space to generate K space data; and generating a magnetic resonance image according to the K space data, and separating a spectrum image of the voxel of interest according to the magnetic resonance image. By adopting the method, the spectrum image of the voxel of interest can be accurately separated.