51 results about "MRI diffusion" patented technology

A new transform is disclosed, applying methods of group theory, with which the composition of a voxel of three channels comprising isotropic, single fiber and multiple fiber components can be determined, as well as the magnitude and orientation of the diffusion field. Asymmetries produced by experimental artifacts fall into channels distinct from the fiber channels, allowing their separation and a subsequent reduction in noise from the reconstructed fibers.

Pulse sequences are applied to a fluid in an earth formation in a static magnetic field having internal gradients. From the received signals, relaxation and diffusion characteristics of the fluid are determined. The determination takes into account the internal field gradients.

A magnetic resonance diagnostic apparatus includes a derivation unit to derive an apparent diffusion coefficient regarding a pixel position for each pixel position included in a region of interest in at least two original images obtained by imaging a same imaging region of a same subject using at least two b-factors that are different from each other, respectively, based on pixel values of each of at least two original images regarding the pixel positions, and a first estimation unit to estimate a pixel value obtained by using a b-factor that is different from the at least two b-factors, regarding each pixel position included in the region of interest, based on the apparent diffusion coefficient derived for each pixel position.

The invention relates to a method for determining ischemic status. The method comprises acquiring magnetic resonance diffusion tensor matrices and obtaining a relative decrease of diffusion magnitude due to the ischemic status from the magnetic resonance diffusion tensor matrices. The invention also relates to a method for assessing stroke onset time. The method comprises acquiring magnetic resonance diffusion tensor matrices and obtaining a relative decrease of pure anisotropy due to stroke from the magnetic resonance diffusion tensor matrices.

In a method and magnetic resonance (MR) system for determining at least one measuring point-in-time in a cardiac cycle for conducting diffusion measurements of the myocardium of an examination object, a sequence of MR images of the heart is acquired and a time curve of a parameter of the cardiac geometry is determined in the sequence of MR images. At least one mean of the parameter of the cardiac geometry is determined from the time curve of the parameter. For the determined at least one mean of the parameter, the associated point-in-time in the time curve of the parameter is determined in which the determined mean occurs, wherein the determined point-in-time defines the at least one measuring point-in-time in a cardiac cycle during which the diffusion measurements of the myocardium are carried out.

The invention discloses a magnetic resonance diffusion imaging data compression and accelerated reconstruction method, which comprises the steps of arranging magnetic resonance data, which is acquired by exciting a sequence for multiple times, of different acquisition coordinates to the same k space coordinates, and simultaneously performing arrangement on image echo signals and navigation echo signals which are acquired by exciting the sequence for multiple times; calculating a compression matrix by using k space data of two-dimensional navigation echo signals according to a preset data scale after compression; and simultaneously performing compression on the image echo data and the navigation signal data by using the acquired compression matrix. The method disclosed by the invention has the following advantages: a rearrangement operation is performed on diffusion imaging data, which is acquired by exciting the sequence for multiple times, of magnetic resonance, data acquired by multiple times of excitation and data acquired by a multi-channel coil are integrated, an excitation-coil dimension of data is constructed so as to perform compression, and the data scale is effectively reduced; effective acceleration is provided for a follow-up magnetic resonance reconstruction algorithm, and memory occupation is reduced at the same time; and image noises are reduced while efficient accelerated calculation is performed, and the image quality is guaranteed.