A method of producing a permanent magnet shim configured to improve a profile of a B.sub.0 magnetic field produced by a B.sub.0 magnet is provided. The method comprises determining deviation of the B.sub.0 magnetic field from a desired B.sub.0 magnetic field, determining a magnetic pattern that, when applied to magnetic material, produces a corrective magnetic field that corrects for at least some of the determined deviation, and applying the magnetic pattern to the magnetic material to produce the permanent magnet shim. According to some aspects, a permanent magnet shim for improving a profile of a B.sub.0 magnetic field produced by a B.sub.0 magnet is provided. The permanent magnet shim comprises magnetic material having a predetermined magnetic pattern applied thereto that produces a corrective magnetic field to improve the profile of the B.sub.0 magnetic field.

A method, system and article of manufacture is disclosed. The method includes providing a spatial navigator outside of a thermal therapy region; receiving a plurality of analog-to-digital conversion (ADC) readouts from an MRI device at a plurality of time points, wherein the ADC readouts comprise a first ADC readout acquired at a first time point, and one or more additional ADC readouts acquired at subsequent time points; processing the ADC readouts to obtain a frequency of the spatial navigator at each of the time points; obtaining a main magnetic field (B.sub.0) drift of the MRI device based on the frequency of the spatial navigator at a particular time point and the frequency of the spatial navigator at the first time point; and obtaining the temperature change at the particular time point based on the B.sub.0 drift.

In a method for control, input magnetic field map data is received. In this case, the input magnetic field map data for at least one magnetic field type in each case describes a magnetic field map for a state that an examination object is in at an initial location in the MR apparatus. In this case, the estimated magnetic field map data for at least one magnetic field type in each case describes at least one magnetic field map for in each case a state that the examination object is in at an alternative location that is different compared to the initial location. Control data is determined by the system control unit, using the estimated magnetic field map data or using the input magnetic field map data and the estimated magnetic field map data. The control data is suitable for controlling the MR apparatus.

Systems and methods for taking into account susceptibility deviations in magnetic-resonance-based therapy planning by a magnetic resonance tomography unit. A B0 field map is determined by the magnetic resonance tomography unit. A location blur distribution is determined from the B0 field map and from the location blur distribution in turn, a parameter of an image acquisition as a function of the location blur distribution, in such a way that an image acquisition brings about a reduced location blur with the determined parameter.

The invention provides for a medical imaging system (100, 300). The medical imaging system comprises a processor (104). Execution of machine executable instructions (120) causes the processor to: receive (200) magnetic resonance imaging data (122) comprising a Z-spectrum acquisition (124) for a set of saturation frequency offsets (126) and at least one reference saturation frequency offset (128); reconstruct (202) saturation frequency offset complex image data (130); reconstruct (204) a B0 map (132), a water image (134), and a fat image (136) according to a Dixon-type magnetic resonance imaging protocol; calculate (206) a water phase angle (138) using the water image and/or the fat image; calculate (208) rotated complex image data (140) by rotating the phase of the saturation frequency offset complex image data such that the complex water signal is aligned with a real axis for each voxel; perform (210) a B0 correction by calculating shifted complex image data (142); calculate (212) a frequency dependent phase angle (144) descriptive of a phase angle between the complex water signal and the complex fat signal for each of the set of saturation frequency offsets using a fat signal model comprising at least two fat species; calculate (214) a residual fat component correction factor (150) by projecting the complex fat signal onto the real axis for each of the set of saturation frequency offsets; and calculate (216) corrected water Z-spectrum image data (152) by subtracting the residual fat component correction factor for each of the set of saturation frequency offsets from the real component of the shifted complex image data.

Accurate measurement of gradient waveform errors can often improve image quality in sequences with time varying readout and excitation waveforms. Self-encoding or offset-slice method sequences are commonly used to measure gradient waveforms. However, the self-encoding method requires a long scan time, while the offset-slice method is often low precision, requiring the thickness of the excited slice to be small compared to the maximal k-space encoded by the test waveform. This disclosure describes a novel hybrid of those methods, referred to as variable-prephasing (VP). Like the offset-slice method, VP uses the change in signal phase from offset-slices to calculate the gradient waveform. Similar to the self-encoding method, repeated acquisitions with a variable amplitude self-encoding gradient mitigates the signal loss due to phase wrapping, which, in-turn, allows thicker slices and greater SNR.

A computerized system and method of modeling myocardial tissue perfusion can include acquiring a plurality of original frames of magnetic resonance imaging (MRI) data representing images of a heart of a subject and developing a manually segmented set of ground truth frames from the original frames. Applying training augmentation techniques to a training set of the originals frame of MRI data can prepare the data for training at least one convolutional neural network (CNN). The CNN can segment the training set of frames according to the ground truth frames. Applying the respective input test frames to a trained CNN can allow for segmenting an endocardium layer and an epicardium layer within the respective images of the input test frames. The segmented images can be used in calculating myocardial blood flow into the myocardium from segmented images of the input test frames.

A variety of application can use nuclear magnetic resonance as an investigative tool. Nuclear magnetic resonance measurements can be conducted using a nuclear magnetic resonance microscope. An example nuclear magnetic resonance microscope can comprise a film embedded in a coverslip, where the film is doped with reactive centers that undergo stable fluorescence when illuminated by electromagnetic radiation having a wavelength within a range of wavelengths and a magnetic field generator to provide a magnetic field for nuclear magnetic resonance measurement of analytes when disposed proximal to the film. Microwave striplines on the coverslip can be arranged to generate microwave fields to irradiate the analytes for the nuclear magnetic resonance measurement. Control of the microwave signals on the microwave striplines can be used for dynamic nuclear polarization in the nuclear magnetic resonance measurement of analytes.

Various embodiments comprise an apparatus to mitigate Electrostatic Discharge (ESD) buildup. In some examples, the apparatus comprises an Optically Pumped Magnetometer (OPM) and a connector. The connector is operatively coupled to the OPM. The OPM is configured to sense magnetic fields. The connector comprises a protective shorting link. The connector is configured to disconnect the protective shorting link in response to coupling and to connect the protective shorting link in response to decoupling.

A method for generating fair and effective random numbers for smart contracts, which effectively mitigates certain problems associated with conventional methods while achieving verifiable and non-tamperable random number generation is disclosed. The concept behind the disclosed method treats miners as being not trustworthy, and presumes that the number of miners in the blockchain is limited. With sufficient motivation, miners can reach a consensus to manipulate the block. The goal is thus to create a verifiable fair Random Number Generator. Under this condition, as long as at least one of the parties to the smart contract is credible and does not misuse the confidential information, a trusted blockchain random number can be generated. After the last disclosure of the random number, the verification signature submitted by parties to the contract can be used to confirm that the random number calculation process is credible.