179 results about "Magnetic resonance spectroscopic" patented technology

A two-dimensional (2D) chemical shift correlated MR spectroscopic (COSY) sequence integrated into a new volume localization technique (90°-180°-90°) for whole body MR Spectroscopy. Using the product operator formalism, a theoretical calculation of the volume localization as well as the coherence transfer efficiencies in 2D MRS is presented. A combination of different MRI transmit/receive rf coils is used. The cross peak intensities excited by the proposed 2D sequence are asymmetric with respect to the diagonal peaks. Localized COSY spectra of cerebral frontal and occipital gray/white matter regions in fifteen healthy controls are presented.

A system and method for automating an appropriate voxel prescription in a uniquely definable region of interest (ROI) in a tissue of a patient is provided, such as for purpose of conducting magnetic resonance spectroscopy (MRS) in the ROI. The dimensions and coordinates of a single three dimensional rectilinear volume (voxel) within a single region of interest (ROI) are automatically identified. This is done, in some embodiments by: (1) applying statistically identified ROI search areas within a field of view (FOV); (2) image processing an MRI image to smooth the background and enhance a particular structure useful to define the ROI; (3) identifying a population of pixels that define the particular structure; (4) performing a statistical analysis of the pixel population to fit a 2D model such as an ellipsoid to the population and subsequently fit a rectilinear shape within the model; (5) repetiting elements (1) through (4) using multiple images that encompass the 3D ROI to create a 3D rectilinear shape; (6) a repetition of elements (1) through (5) for multiple ROIs with a common FOV. A manual interface may also be provided, allowing for override to replace by manual prescription, assistance to identify structures (e.g. clicking on disc levels), or modifying the automated voxel (e.g. modify location, shape, or one or more dimensions).

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 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.

An antenna (100) for a magnetic resonance device has a predetermined sensitivity and is designed to excite and/or detect a magnetic resonance in an object under test. The antenna (100) includes a stripline resonator (10) that is equipped with at least one stripline (11), and a conductor loop arrangement (20) that adjoins the stripline resonator (10) and forms at least one conductor loop (21, 22, 28) which is interrupted by at least one capacitor (23). The sensitivity of the antenna (100) is formed by overlapping sensitivity profiles of the stripline resonator (10) and the conductor loop arrangement (20). Also described are an antenna array (200) including a plurality of antennas (100), a magnetic resonance device (300) including at least one antenna (100) or antenna array (200), and methods for magnetic resonance imaging or magnetic resonance spectroscopy.

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.

A method for magnetic resonance spectroscopy (=MRS) or magnetic resonance imaging (=MRI) in which an NMR time-domain signal is created by an RF excitation pulse applied to an object in the presence of an applied magnetic field that may depend on spatial position and/or time, the time-domain signal being generated by an excited transverse nuclear magnetisation precessing about the applied magnetic field, whereby the RF excitation pulse is adapted to cover a whole range of NMR frequencies of interest present in the object, and time-domain signal acquisition takes place during, or during and after the application of the RF excitation pulse, is characterized in that spectral or image data are reconstructed by a matrix product of a reconstruction matrix and a vector of time-domain signal points, the reconstruction matrix being an inversion of an encoding matrix A_nα whose elements are calculated using the formula:

wherein n is the running number of a time-domain signal point, α is the running number of a discrete image or spectral element, P_m is the m-th discrete element of the RF excitation pulse in the time-domain, and Φ(n,m,α) is the phase accrued by the transverse nuclear magnetisation related to the discrete image or spectral element a in the time between the discrete RF excitation pulse element P_m and the time-domain signal point n under the influence of the applied magnetic field. An improved method for reconstructing spectral or image data from time-domain signal acquired as describe above is thereby provided which can be used more versatilely than conventional Fourier transform.

A method for classifying a possible cancer from a magnetic resonance spectrographic (MRS) dataset includes extracting at least one feature from the MRS dataset as being identified with the possible cancer and embedding the extracted feature into a low dimensional space to form an embedded space. The method then clusters the embedded space into clusters representing a plurality of predetermined classes and spectrally decomposing the clusters to identify substantially significant independent metabolic signatures. The method then classifies the possible cancer as belong to one of at least two cancer classes based on the identified independent metabolic signatures.

The invention discloses a quick reconstruction method for under-sampling magnetic resonance spectra, and relates to magnetic resonance spectra. The method comprises the steps of firstly, performing under-sampling on time domain signals of magnetic resonance spectra, and filling a Hankel matrix with sampling data; then reconstructing complete time domain signals by using the low rank characteristic of the matrix, and performing Fourier transformation to obtain high-quality spectra, wherein in the process, the minimization of a matrix nuclear norm item is approached by using a matrix factorization method and minimizing a matrix Frobenius norm item, so that singular value decomposition used when the nuclear norm item is solved is avoided, and the effect of accelerating reconstruction is achieved. The method is excellent in effect and easy to operate, and can be applied to under-sampling magnetic resonance spectrum reconstruction of one, two and higher dimensions.

A method is provided for producing, with a magnetic resonance (MR) system, a nuclear magnetic resonance spectrum that has been corrected for errors arising from phase offsets and time shifts in the acquired spectroscopic data. A spectroscopic data set includes temporal information indicative of the underlying phase offsets and time shifts. In general, this temporal information is utilized to correct for errors in the acquired data. As a result, a plurality of acquired spectroscopic data sets are more accurately combined by first individually correcting each spectroscopic data set for such errors. Exemplary sources of the phase offsets and time shifts include the physical separation between a volume of interest and the detectors in the MRI system. Using the temporal information, T₂ decay in the produced spectrum is also corrected.

The invention discloses a magnetic resonance spectrum reconstruction method based on a block Hankel matrix. The method comprises the following steps: firstly acquiring a magnetic resonance signal under-sampling template, constructing a block Hankel matrix of a two-dimensional matrix, and establishing a low-rank reconstruction model based on the block Hankel matrix of a magnetic resonance free attenuation signal; and then solving the reconstruction model through an iteration algorithm and acquiring a reconstructed free attenuation signal; and finally performing the Fourier transform to obtain a complete magnetic resonance spectrum. The reconstruction method disclosed by the invention is small in required sampling data amount, high in precision, and capable of reconstructing a complete magnetic resonance spectrum from less under-sampling data; the sampling speed of the method provided by the invention is faster than that of the existing method under the condition of obtaining the reconstructed spectrum data with the same quality.

Methods and/or apparatuses for magnetic resonance imaging (MRI) and/or magnetic resonance spectroscopy comprising a superconducting gradient coil module configured for cryogenic cooling. Such a superconducting gradient coil module may comprise a vacuum thermal isolation housing comprising a double wall hermetically sealed jacket that (i) encloses a hermetically sealed interior space having a first vacuum pressure, and (ii) substantially encloses a vacuum space having a second vacuum pressure; at least one superconductor gradient coil disposed in the vacuum space; a thermal sink member disposed in the vacuum space and in thermal contact with the at least one superconductor gradient coil; and a port configured for cryogenically cooling at least the thermal sink member.

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 provides an exponential signal denoising method achieved by means of prior information and relates to a denoising method for exponential signals.The prior exponential signals form a Hankel matrix according to a set sequence, the Hankel matrix is subjected to singular value decomposition, and a prior signal space and a prior singular value are obtained; then a Hankel matrix with the same size as the former Hankel matrix is established for the target exponential signals, and the matrix of the target signals is decomposed through the prior information space; after a weighted threshold is obtained from the prior singular value, a Hankel matrix of the denoised target signals is obtained from the singular value of the target exponential signals according to the weighted threshold; then the Hankel matrix of the target signals is solved, and finally the denoised signals are obtained.Through the prior information of the reference signals, the speed is high, the effect is good, and operation is easy.Denoising of a magnetic resonance spectrum can be achieved for signals with exponential features such as time domain signals of the magnetic resonance spectrum through the method, and the purposes of shortening the sampling time and increasing the signal to noise ratio of the spectrum are achieved.

The invention discloses a rapid super-complex magnetic resonance spectrum reconstruction method, relates to magnetic resonance spectrums, and provides a method for reconstructing complete magnetic resonance spectrums from under-sampled super-complex magnetic resonance spectrums. The method comprises the following steps of: firstly filling an obtained under-sampled super-complex magnetic resonance spectrum into a blocked Hankel matrix; converting the super-complex blocked Hankel matrix into a super-complex companion matrix; constructing a reconstruction model, a nuclear norm of which corresponding to the super-complex companion matrix is minimized; and finally solving the reconstruction model by adoption of a rapid algorithm, so as to obtain a complete magnetic resonance spectrum.