A magnetic resonance (MR) system for correcting concomitant field effects is provided. The MR system includes a gradient coil assembly including a plurality of gradient coils configured to apply at least one gradient field to a polarizing magnetic field of the MR system. The MR system also includes a second-order correction coil assembly including a first second-order correction coil configured to correct effects of a first term of second-order concomitant fields generated by the at least one gradient field. The system further includes a second-order correction computing device including at least one processor in communication with at least one memory device. The at least one processor is programmed to control the second-order correction coil assembly by instructing the MR system to apply a compensation field to the second-order correction coil assembly asynchronously with the at least one gradient field.

Magnetic Resonance Imaging (MRI), which is given the acronym ULTRA (Unlimited Trains of Radio Acquisitions), can eliminate magnetic gradient reversals and allow simultaneous MR signal acquisition from the entire object volume in each of a multitude of very small receiver coils arranged in a 3D array around the imaging volume. This permits a rate of MR signal acquisition that is greatly increased (e.g. 256 times) compared with existing techniques, with a full 3D image constructed in as little as 1 millisecond. Furthermore, noiseboth audible and electricalis substantially reduced. The advantages over conventional MRI include: 1. Clinical imaging can be completed in seconds or less, with good signal-to-noise ratio; 2. Signal-to-noise ratio further increased by eliminating RF noise due to gradient switching; 3. Real-time functional MRI on millisecond timescales; 4. With single breath holds, high quality imaging of thorax and abdomen. 5. Greatly reduced audible noise and vibration.

Variable flip angle techniques with constraints for reconstructing MR images include a processor generating a T.sub.1app map representing a spatial distribution of T.sub.1app within an anatomical region using a first MR dataset corresponding to a first flip angle (FA) and a second MR dataset corresponding to a second FA. The processor can estimate a first and second transmit RF field maps by scaling the T.sub.1app map by a first constant value of T.sub.1 associated with a first tissue type and a second constant value of T.sub.1 associated with a second tissue type, respectively. The processor can generate a third transmit RF field map using the first and second transmit RF field maps, and use the third transmit RF field map to construct MR images of the anatomical region. Weighted subtraction images can be created with improved contrast-to-noise ratio compared to images of the first and second MR datasets.

Systems and methods for combined ghost artifact correction and parallel imaging reconstruction of simultaneous multislice (SMS) magnetic resonance imaging (MRI) data are provided. Dual-polarity training data are used to generate ghost-free slice data, which are used as target data in a reconstruction kernel training process. The training data are used as source data in the reconstruction kernel training. As a result, reconstruction kernels are computed, which can be used to reconstruct images from SMS data in which slice-specific ghosting artifacts are removed.

Methods, systems, computer programs, circuits and workstations are configured to generate MRI images using gradient blips for signal acquisition and reconstruction using dynamic field mapping, TE corrections and/or multischeme partial Fourier images.

A magnetic resonance method and system are provided for providing improved simultaneous multislice echo planar imaging (EPI) with navigator-based correction of image data for B0 drift and N/2 ghosting. The correction is based on two types of multi-echo phase-encoded navigator sequences having opposite readout gradient polarities, and optionally also uses a non-phase-encoded navigator sequence. One or more navigator sequences can be generated between each RF excitation pulse and the subsequent EPI readout sequence. A dynamic off-resonance in k-space technique can be used to correct for B0 drift, and a modified slice GRAPPA technique that is based on odd and even kernels can provide slice-specific correction for N/2 ghosting effects for the EPI MR image data sets. Various patterns of navigator sequences and/or interpolation of navigator data can be used to improve accuracy of the image data corrections.

Techniques are provided for performing echo planar imaging (EPI) data correction. This includes obtaining positive and negative readout gradient calibration data of an imaging target through non-accelerated EPI acquisitions; respectively adopting first and second DPG kernels to be fitted and respectively used to eliminate phase errors of positive and negative readout gradients to fit the positive and negative readout gradient calibration data of the imaging target, with the fitting targets being positive and negative readout gradient data, respectively, in ghost-free target ACS data, and obtaining, after the fitting, a first and a second DPG kernel for final use; obtaining imaging data of the imaging target through an EPI acquisition; adopting the first and second DPG kernels to correct the phase errors of the imaging data to obtain phase-error-free imaging data.

Disclosed herein is a medical system (100, 300) comprising a memory (110) storing machine executable instructions (120) and an image generating neural network (122). The image generating neural network is configured for outputting synthetic magnetic resonance image data (128) in response to receiving reference magnetic resonance image data (126) as input. The synthetic magnetic resonance image data is a simulation of magnetic resonance image data acquired according to a first configuration of a magnetic resonance imaging system when the reference magnetic resonance image data is acquired according to a second configuration of the magnetic resonance imaging system. Execution of the machine executable instructions causes a computational system (106) to: receive (200) measured k-space data (124) acquired according to the first configuration of the magnetic resonance imaging system; receive (202) the reference magnetic resonance image data; receive (204) the synthetic magnetic resonance image data by inputting the reference magnetic resonance image data into the image generating neural network; and reconstruct (206) corrected magnetic resonance image data (132) from the measured k-space data and the synthetic magnetic resonance image data.

Disclosed herein is a medical system (100, 300) where execution of machine executable instructions (120) causes a computational system (104) to: receive (200) a time series of a R2-star map (122) for a brain volume (500); receive (202) a stimulus signal (124) descriptive of an occurrence of a sensory stimulus; receive (204) a selection of one or more seed voxels (126) identified in the time series of the R2-star map; calculate (206) a denoised time series of the R2-star map (128); calculate (208) a correlation map (130) between the seed voxels and the denoised time series of the R2-star map; determine (210) an activated region (132) of the brain volume using voxels identified in the correlation map; provide (212) a hemodynamic response (134) function for each voxel and each occurrence of the sensory stimulus; and provide (214) a subject specific hemodynamic response function (136) by averaging the hemodynamic response functions.

In a magnetic resonance readout-segmented diffusion-weighted imaging method, apparatus, and storage medium, a non-linear phase RF excitation pulse is applied to nuclear spins that exhibit a magnetization intensity vector, and applying, in a slice selection direction, a slice selection gradient pulse of duration corresponding to the non-linear phase RF excitation pulse, so as to flip the magnetization intensity vector into the X-Y plane. Diffusion weighting is performed on the magnetization intensity vector flipped into the X-Y plane. A readout-segmented sampling sequence is executed to read out raw data in a segmented manner from the magnetization intensity vector resulting from diffusion weighting. A view angle tilting gradient pulse is applied in the slice selection direction.