The invention provides for a medical imaging system (100, 300) comprising: a memory (110) for storing machine executable instructions (120); and a processor (104) for controlling the medical imaging system. Execution of the machine executable instructions causes the processor to: receive (200) a resting group of B1 phase maps (122) of a region (309) of interest of a subject (318); receive (202) an active group of B1 phase maps (124) of the region of interest of the subject, calculate (204) a resting group of conductivity maps (126) for the region of interest using the resting group of B1 phase maps according to an electrical properties tomography algorithm; calculate (206) an active group of conductivity maps (128) for the region of interest using the active group of B1 phase maps according to the electrical properties tomography algorithm, and calculate (208) a conductivity change mapping (130) for the region of interest using the resting group of conductivity maps and the active group of conductivity maps.

The invention provides for a magnetic resonance imaging system (100) for acquiring MRF magnetic resonance data (144) from a subject (118) within a region of interest (109). The magnetic resonance imaging system comprises a processor (130) for controlling the magnetic resonance imaging system and a memory (134) for storing machine executable instructions (140) and MRF pulse sequence commands (142). The MRF pulse sequence commands are configured for controlling the magnetic resonance imaging system to acquire the MRF magnetic resonance data according to a magnetic resonance fingerprinting protocol. Execution of the machine executable instructions causes the processor to: acquire (200) the MRF magnetic resonance data for the region of interest by controlling the magnetic resonance imaging system with the MRF pulse sequence commands; receive (202) at least one magnetic resonance image (152) descriptive of the region of interest; identify (204) anatomical regions (156) within the region of interest using an anatomical model (154); select (206) a local magnetic resonance fingerprinting dictionary (158) from a set of magnetic resonance fingerprinting dictionaries for each of the anatomical regions, wherein the local magnetic resonance fingerprinting dictionary comprises a listing of calculated MRF signals for a set of predetermined substances specific to each of the anatomical regions; and calculate (208) a composition mapping (160) of the predetermined substances for each of the anatomical regions using the MRF magnetic resonance data and the local magnetic resonance fingerprinting dictionary, wherein the composition mapping is a spatial average within each of the anatomical regions.

A magnetic resonance imaging (MRI) system (100) includes a memory (134) for storing machine executable instructions (140) and magnetic resonance fingerprinting (MRF) pulse sequence commands (142) which cause the MRI system to acquire MRF magnetic resonance data (144) according to an MRF protocol. The pulse sequence commands are configured for acquiring the MRF magnetic resonance data in two-dimensional slices (410, 412, 414, 416, 418, 420), having a slice selection direction. A train of pulse sequence repetitions includes a sampling event where the MRF data is repeatedly sampled. Execution of the machine executable instructions causes a processor to control the MRI system to: acquire (200) the MRF magnetic resonance data; construct (202) a series (148) of at least one magnetic resonance parameter value for each voxel of the two dimensional slices; and calculate (204) a composition (502, 504, 506, 508) of each of a set of predetermined substances within two or more sub-voxels (306, 308) for each voxel of the two dimensional slices using a sub-voxel magnetic resonance fingerprinting dictionary (150) for each of the two or more sub-voxels and the series of the at least one magnetic resonance parameter value. Each voxel in the slice selection direction is divided into two or more sub-voxels.

A system and method is provided for correcting receiver bias during quantitative proton density mapping with magnetic resonance fingerprinting (MRF). The method comprises acquiring MRF data from a region of interest in a subject by performing a pulse sequence using a series of varied sequence blocks to elicit a series of signal evolutions. The method further comprises comparing the MRF data to a MRF dictionary to simultaneously map proton density and another tissue property from the region of interest, the proton density map having a proton density signal and a receiver sensitivity profile signal. The method also includes quantifying the proton density signal and the receiver sensitivity profile signal using parameters provided by the proton density map and the tissue property map, and generating a quantitative map from the region of interest based on the proton density signal.

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 .sup.1H-MRSI scan.

The present invention relates to a method for performing electrical impedance tomography (EIT) by an MR system, wherein during the MR measurement continuous RF signals for an EIT measurement are emitted by at least one RF coil of the MR system, and continuous RF signals modulated by the object undergoing examination are received by the receiving coils of the MR system. An image of the object undergoing examination is determined, based on the modulated continuous RF signals, by an EIT technique.

The invention provides for a magnetic resonance imaging system (100) for acquiring MRF magnetic resonance data (144) from a subject (118) within a region of interest (109). The magnetic resonance imaging system comprises a processor (130) for controlling the magnetic resonance imaging system and a memory (134) for storing machine executable instructions (140) and MRF pulse sequence commands (142). The MRF pulse sequence commands are configured for controlling the magnetic resonance imaging system to acquire the MRF magnetic resonance data according to a magnetic resonance fingerprinting protocol. Execution of the machine executable instructions causes the processor to: acquire (200) the MRF magnetic resonance data for the region of interest by controlling the magnetic resonance imaging system with the MRF pulse sequence commands; receive (202) at least one magnetic resonance image (152) descriptive of the region of interest; identify (204) anatomical regions (156) within the region of interest using an anatomical model (154); select (206) a local magnetic resonance fingerprinting dictionary (158) from a set of magnetic resonance fingerprinting dictionaries for each of the anatomical regions, wherein the local magnetic resonance fingerprinting dictionary comprises a listing of calculated MRF signals for a set of predetermined substances specific to each of the anatomical regions; and calculate (208) a composition mapping (160) of the predetermined substances for each of the anatomical regions using the MRF magnetic resonance data and the local magnetic resonance fingerprinting dictionary, wherein the composition mapping is a spatial average within each of the anatomical regions.

A method and system for determining a magnetic field map in a MR system based on position of a movable patient support of the MR system are provided, wherein a first resulting field map including position dependent information about a magnetic field distribution in a homogeneity volume including an examination volume of the MR system is provided when the movable patient support is located at a first position, wherein a stationary field map including information about a magnetic field distribution in the homogeneity volume is provided, which is independent of the position of the movable patient support, wherein a position dependent field map including information about a magnetic field distribution in the homogeneity volume mainly influenced by a position of the movable patient support is determined using the stationary field map and the first resulting field map, and wherein a second resulting field map in the homogeneity volume is determined when the movable patient support is located at a second position different from the first position, using the stationary field map and the position dependent field map.

A computer-implemented method is disclosed for providing an actuation sequence which specifies transmit signals for at least one high-frequency transmit channel of an antenna arrangement of a magnetic resonance device for acquiring measurement data of an object under investigation by the magnetic resonance device. The method includes providing different actuation sequences, wherein each sequence is the result of an optimization method and which differs with regard to the value of an optimization parameter taken into account in the course of the optimization method. The method further includes providing a plurality of field distribution maps, (e.g., at least one B.sub.0 map and/or at least one B.sub.1 map), acquired by the or a further magnetic resonance device from the object under investigation. The method further includes selecting the actuation sequence to be used from the different actuation sequences depending on the field distribution maps and providing the actuation sequence to be used.

Embodiments of the present invention provide a magnetic resonance imaging method and system and a computer-readable storage medium. The method comprises: performing pre-scanning, wherein a first sequence and a second sequence are separately performed on a plurality of slices; in the first sequence, two echoes are continuously obtained to respectively obtain first image data and second image data having a first phase offset; in the second sequence, two echoes are continuously obtained to respectively obtain third image data and fourth image data having a second phase offset, the first phase offset and the second phase offset having opposite directions but the same angle; obtaining a plurality of radio-frequency field maps respectively corresponding to the plurality of slices based on the first image data and the second image data, and obtaining a plurality of static magnetic field maps respectively corresponding to the plurality of slices based on at least one of the following two groups: a first image and a third image, and a second image and a fourth image; and calculating formal scanning parameters suitable for a corresponding slice based on at least one of the following two components: each radio-frequency field map, and a corresponding static magnetic field map.