In a magnetic resonance (MR) apparatus and an operating method therefor, the MR apparatus has multiple reception coils each having an associated reception channel, a reference dataset is obtained from an examination volume of a subject, wherein the reference dataset completely fills a region of k-space. In a computer, a subregion of the examination volume is determined that has a lower homogeneity than other subregions of the examination volume, and the computer also determines at least one of the reception channels in which raw data signals are received that have a higher intensity in the determined subregion than others of the reception channels. The computer calculates a weighting matrix, in which signals, the determined reception channel are given a lower weighting than signals from the other channels. The weighting matrix is then applied to diagnostic data acquired with parallel imaging using the multiple reception coils and channels.

Systems and methods for accelerated diffusion-weighted magnetic resonance imaging using a tilted reconstruction kernel to synthesize unsampled k-space data in phase encoded and point spread function (PSF) encoded k-space data are provided. Images reconstructed from the data have reduced B.sub.0-related distortions and reduced T.sub.2* blurring. In general, data are acquired with systematically optimized undersampling of the PSF and phase encoding subspace. Parallel imaging reconstruction is implemented with a B.sub.0 inhomogeneity informed approach to achieve greater than twenty-fold acceleration of the PSF encoding dimension. A tilted reconstruction kernel is used to exploit the correlations in the phase encoding-PSF encoding subspace. Self-navigated phase corrections are computed from the acquired data and used to synthesize the unsampled k-space data.

Techniques are provided for image reconstruction in parallel MR imaging, in which a respective set of regularly undersampled MR measurement data in k-space representing an imaged object is received for each of a plurality of coil channels. For each pair of coil channels of the plurality of coil channels, a respective set of reconstruction weights for reconstructing MR data at k-space points, which are not measured according to the undersampling, from the MR measurement data, is received. For each of the plurality of coil channels, a respective coil sensitivity map is determined depending on the respective sets of reconstruction weights for the respective coil channel. A reconstructed MR image is generated based on the coil sensitivity maps.

An asymmetric 3D shells k-space trajectory design with partial Fourier acceleration is described. A non-iterative homodyne reconstruction framework is also described.

A method of designing a pulse sequence for parallel-transmission magnetic resonance imaging comprises: a) acquiring, for each member of a cohort, inhomogeneity maps of radio-frequency fields generated within the member; b) computing, for each member of the cohort, a spatial distribution of flip angles of nuclear spins obtained using the pulse sequences, and c) computing a single cost or merit function representative of a difference between the spatial distributions of flip angles and a target distribution, and iteratively adjusting design parameters of the pulse sequences to optimize the cost or merit function; the steps b) and c) being carried out iteratively using a computer. A method of performing parallel-transmission magnetic resonance imaging on a subject using a pulse sequence designed by such a method is provided.

According to one embodiment, a magnetic resonance imaging apparatus provided with a plurality of transmission channels includes a signal processing unit and a control unit. The signal processing unit acquires a radio frequency magnetic field emitted from each of the plurality of transmission channels through a receiver coil mounted on an object and measure a phase of the radio frequency magnetic field. The control unit determines a phase difference between the plurality of transmission channels based on the phase of the radio frequency magnetic field of each of the plurality of transmission channels measured by the signal processing unit. The control unit controls a phase of a radio frequency pulse inputted to each of the plurality of transmission channels, based on the phase difference.

The invention provides for medical instrument (200, 400) comprising a magnetic resonance imaging system (202) and a high intensity focused ultrasound system (222). A processor (246) controls the medical instrument. Instructions cause the processor to control (100) the magnetic resonance imaging system to acquire the magnetic resonance data using a pulse sequence (254). The pulse sequence comprises an acoustic radiation force imaging pulse sequence (500, 600). The acoustic radiation force imaging pulse sequence comprises an excitation pulse (512) and a multi-dimensional gradient pulse (514) applied during the radio frequency excitation pulse for selectively exciting a region of interest (239) encompassing a target zone and at least a portion of the beam axis. The instructions cause the processor to control (102) the high intensity focused ultrasound system to sonicate the target zone during the acoustic radiation force imaging pulse sequence and reconstruct (104) a radiation force image (258) using the magnetic resonance data.

A method includes using fully sampled retro cine data to train an algorithm, and applying the trained algorithm to real time MR cine data to yield reconstructed MR images.

A method for calculating an operating parameter of a magnetic resonance sequence, a magnetic resonance apparatus, and a computer program product are disclosed. According to the method, at least one initial sequence parameter of a radio-frequency (RF) transmit pulse of the magnetic resonance sequence is provided. In addition, at least one test RF transmit pulse is determined, (e.g., calculated and/or modeled and/or simulated), wherein the at least one test RF transmit pulse is adapted based on the at least one initial sequence parameter to a specified, in particular geometric, standard shape. The at least one operating parameter is determined, (e.g., calculated), with the assistance of the at least one test RF transmit pulse. It is in particular assumed in this respect that the at least one test RF transmit pulse is applied on performance of the magnetic resonance sequence.

The invention provides for a magnetic resonance imaging system (200, 300, 400) comprising a radio-frequency system (216, 214) comprising multiple coil elements (214) for acquiring magnetic resonance data (264). The magnetic resonance imaging system further comprises a memory (250) for storing machine executable instructions (260) and pulse sequence commands (262). The pulse sequence commands are configured for controlling the magnetic resonance imaging system to acquire the magnetic resonance data according to a SENSE imaging protocol. The magnetic resonance imaging system further comprises a processor (244) for controlling the magnetic resonance imaging system. Execution of the machine executable instructions causes the processor to: control (500) the magnetic resonance imaging system to acquire the magnetic resonance data using the pulse sequence commands; reconstruct (502) a set of folded magnetic resonance images (266) from the magnetic resonance data; calculate (504) a voxel deformation map (270) from a static magnetic field (B0) inhomogeneity map; calculate (506) a set of unfolding matrices (274) using a least partially a coil sensitivity matrix (272) for the multiple coil elements, wherein the set of unfolding matrices comprises at least one modified unfolding matrix, wherein the at least one modified unfolding matrix is calculated at least partially using the a coil sensitivity matrix and the voxel deformation map; and calculate (508) undistorted magnetic resonance image data (276) using the set of folded magnetic resonance images and the set of unfolding matrices.