The invention relates to a method of MR imaging of an object (10) placed in an examination volume of a MR device (1). It is an object of the invention to enable MR signal acquisition in a single scan providing the necessary information for electric properties imaging (EPT), namely a phase map as well as tissue boundaries. The method of the invention comprises the following steps: —subjecting the object (10) to a multi echo steady state imaging sequence or a fast spectroscopic imaging sequence comprising RF pulses and switched magnetic field gradients, wherein two or more echo signals are generated after each RF excitation; —acquiring the echo signals; —deriving a magnitude image and a phase map from the acquired echo signals, which phase map represents the spatial RF field distribution induced by the RF pulses in the object (10); and —reconstructing an electric conductivity map from the magnitude image and from the phase map, wherein tissue boundaries are derived from at least the magnitude image. Moreover, the invention relates to a MR device for carrying out this method as well as to a computer program to be run on a MR device.

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.

Systems and methods for magnetic resonance imaging, including adjusting spatial distribution of a rotating magnetic field. By minimizing imaging time, the B.sub.1 nonuniformity reducing effect of RF shimming is maximized for an imaging section of an arbitrary axis direction and an arbitrary position. B.sub.1 distributions are measured for only several sections of one predetermined direction, and a radio frequency magnetic field condition that maximizes the B.sub.1 non-uniformity reducing effect for an imaging section of an arbitrary direction and an arbitrary position is calculated from the B.sub.1 distribution data.

According to one embodiment, a magnetic resonance imaging apparatus includes processing circuitry. The processing circuitry calculates power of a first RF magnetic field required for excitation at a first flip angle in a first target slice, acquires information on inhomogeneity of a transmission RF magnetic field for a cross section crossing the first target slice, and calculate power of a second RF magnetic field required for excitation at a second flip angle in a second target slice different from the first target slice for the cross section by using the information and the first RF magnetic field power.

Determining parameter values in image points of an examination object in an MR system by an MRF technique. Comparison signal waveforms, established using predetermined recording parameters, and each assigned to predetermined values of the parameters to be determined, are loaded. An image point time series of the examination object is acquired with an MRF recording method such that the acquired image point time series are comparable with the loaded comparison signal waveforms. A signal comparison of a section of the respective signal waveform of the acquired one image point time series is carried out with a corresponding section of loaded comparison signal waveforms to establish similarity values. The values of the parameters to be determined on the basis of the most similar comparison signal waveforms determined are determined, and then stored or output.

The invention provides for a magnetic resonance imaging system (100) comprising a radio frequency system (116, 114, 118) configured for acquiring magnetic resonance data (144) from an imaging zone (108). The radio frequency system is configured for sending and receiving radio frequency signals to acquire the magnetic resonance data, wherein the radio frequency system comprises: an elliptical transmission coil (114) configured for generating a B1+ excitation field within the imaging zone; and an active B1 shim coil (118) configured for being placed within the imaging zone, wherein the radio frequency system is configured for suppling radio frequency power to the active B1 shim coil during the generation of the B1+ excitation field by the elliptical transmission coil, wherein the B1 shim coil is configured for shimming the B1+ excitation field within the imaging zone.

Magnetic resonance fingerprinting (“MRF”) techniques in which T1, T2, and T2* are simultaneously quantified using a combined gradient echo and spin echo acquisition with integrated B1 correction are described. The values for T2 and T2* can be estimated separately, but using the same underlying dictionary. This approach enables a smaller dictionary size that is easily manageable, and also reduced error propagation. Moreover, by using echo planar imaging (“EPI”) readouts, the raw MRF images will have higher signal-to-noise ratio (“SNR”) relative images acquired using spiral-based MRF techiques. The EPI-based images are also relatively free of artifacts. Together, these advantages lead to the need for far fewer frames, thereby enabling much faster acquisitions. Moreover, offline reconstruction is not needed, allowing for a more straightforward implementation of MRF.

Apparatus for imaging during surgical procedures includes an operating room for the surgical procedure and an MRI for obtaining images periodically through the surgical procedure by moving the magnet up to the table. The magnet wire is formed of a superconducting material such as magnesium di-boride or Niobium-Titanium which is cooled by a vacuum cryocooling system to superconductivity without use of liquid helium. The magnet weighs less than 1 to 2 tonne and has a floor area in the range 15 to 35 sq feet so that it can be carried on the floor by a support system having an air cushion covering the base area of the magnet having side skirts so as to spread the weight over the entire base area. The magnet remains in the room during surgery and is powered off to turn off the magnetic field when in the second position remote from the table.

A method of processing magnetic resonance data of a sample under investigation includes the steps of provision of the MR data being collected with an MRI scanner apparatus, and machine learning based data analysis of the MR data by supplying the MR data to an artificial neural network being trained with predetermined training data, wherein at least one image parameter of the sample and additionally at least one uncertainty quantification measure representing a prediction error of the at least one image parameter are provided by output elements of the neural network. Furthermore, a magnetic resonance imaging (MRI) scanner apparatus being adapted for employing the method of processing MR data is described.

Diffusion sensitizing gradient pulse pairs are prescribed in a manner to mitigate effects of concomitant gradient artifacts. Measured MR signals generated by applying a plurality of diffusion sensitizing gradient matrices are obtained and processed to determine a second order mean diffusion tensor and a fourth order covariance tensor. Quantities derived from these tensors are measured and mapped within an imaging volume which describe features of diffusion anisotropy and heterogeneity within each imaging voxel.