The present disclosure discloses a magnetic resonance CEST imaging sequence and device based on a frequency stabilization module. It includes following steps: first, in the frequency stabilization module, exciting a target slice with a small-flip-angle radio frequency pulse, and collecting three lines of non-phase-encoded k-space data; second, obtaining a fine estimated value of a frequency drift of a main magnetic field by calculating a phase difference between the first and second lines of non-phase encoded k-space data; then obtaining a coarse estimated value of the frequency drift of the main magnetic field by calculating a difference between a phase difference between the second and third lines and the phase difference between the first and second lines; then determining the value of the frequency drift of the main magnetic field by comparing a difference between the coarse estimated value and the fine estimated value with a threshold; then adjusting a center frequency of the radio frequency pulse based on the calculation result of the frequency drift of the main magnetic field, to realize a real-time correction of the frequency drift of the main magnetic field; and finally, performing conventional magnetic resonance CEST imaging. The present disclosure realizes the real-time correction of the frequency drift of the main magnetic field during magnetic resonance CEST imaging and ensures effective suppression on fat signals, thereby improving magnetic resonance CEST imaging performance.

Systems and methods are provided for producing hyperpolarized materials for use during a magnetic resonance imaging (MRI) or nuclear magnetic resonance (NMR) process. The system and methods include the use of microfluidic and/or microreactor methods in one or more of the stages of parahydrogen production, enriched substrate production, and spin order transfer from the parahydrogen to a substrate.

The present disclosure provides a system for MRI. The system may obtain a plurality of echo signals relating to a subject that are excited by an MRI pulse sequence applied to the subject. The system may perform a quantitative measurement on the subject based on the plurality of echo signals. The MRI pulse sequence may include a CEST module configured to selectively excite exchangeable protons or exchangeable molecules in the subject, an RF excitation pulse applied after the CEST module configured to excite a plurality of gradient echoes, and one or more refocusing pulses applied after the RF excitation pulse. In some embodiments, the quantitative measurement may include determining various quantitative parameters including a T1, a T2, a T2*, an R2 value, an R2* value, an R2′, a B0 field, a pH value, an MWF, and an APT simultaneously.

A method for controlling a magnetic resonance imaging system, including: selecting a plurality of spatially non-selective initial RF-pulses each having a predefined pulse shape and a predefined frequency; determining a combined RF-pulse from the initial RF-pulses by choosing a time-offset comprising a relative application time-shift between the initial RF-pulses, wherein this time-offset is chosen such that the initial RF-pulses overlap; and including the combined RF pulse in a pulse sequence applied in a magnetic resonance imaging system.

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.

A magnetic resonance pulse sequence technique may acquire a water reference spectrum and two water suppressed metabolite spectra and with frequency selective inversion pulse centered at either single frequency, at multiple frequencies, or in a single acquisition. Subtraction of the inverted from non-inverted water suppressed metabolite spectrum results in single or a combination of specific metabolite peak/peaks alone with a flat baseline for easier quantification.

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.

A magnetic resonance imaging apparatus includes sequence controlling circuitry configured: to obtain, during a time period after excitation of a first nuclide in a hyperpolarized state but no later than before obtainment of a first magnetic resonance signal from the first nuclide, a second magnetic resonance signal from a second nuclide that is different from the first nuclide and is in a non-hyperpolarized state, by exciting the second nuclide; and to control each of gradient magnetic field waveforms so as to cause both a first sum indicating a sum of application amounts of a gradient magnetic field related to the excitation of the second nuclide and a second sum indicating a sum of application amounts of a gradient magnetic field related to the obtainment of the second magnetic resonance signal to be close to zero, no later than before the obtainment of the first magnetic resonance signal.

The disclosure relates to techniques for perming chemical exchange saturation transfer (CEST) imaging correction. The present disclosure improves the speed of correcting CEST images.

Nuclear spins are excited in a region of interest in an object under examination by a radio-frequency pulse. During at least one phase of the radio-frequency pulse, excitation fields are transmitted while magnetic field gradients are simultaneously applied so that the magnetization of the nuclear spins moves on a trajectory through a transmission k-space. In a first phase of the at least one phase of the radio-frequency pulse, the trajectory moves at a radial distance around the center of the transmission k-space. The radial distance corresponds to the radius of a sphere superimposed with at least one radial harmonic.