It is proposed a method for post-processing images of an region of interest in a subject, the images being acquired with a magnetic resonance imaging technique, the method for post-processing comprising at least the step of:unwrapping the phase of each image,extracting a complex signal over echo time for at least one pixel of the unwrapped images, andcalculating fat characterization parameters by using a fitting technique applied on a model, the model being a function which associates to a plurality of parameters each extracted complex signal, the plurality of parameters comprising at least two fat characterization parameters, the magnitude error and the phase error generated by the use of the bipolar readout gradients, the fitting technique being a non-linear least-square fitting technique using pseudo-random initial conditions.

A system and method for magnetic resonance imaging is provided. The method includes dividing k-space into a plurality of regions along a dividing direction; scanning an object using a plurality of sampling sequences; acquiring a plurality of groups of data lines; filling the plurality of groups of data lines into the plurality of regions of the k-space; and reconstructing an image based on the filled k-space.

In a method and a magnetic resonance (MR) system, a marked area is determined that demarcates a predetermined volume segment of the subject relative to the regions adjacent thereto. Nuclei in the predetermined volume segment are excited, or nuclei in a region adjacent thereto are saturated with an RF excitation pulse at the same time a magnetic field gradient is activated. The center frequency of a frequency range of the RF excitation pulse and the direction of the magnetic field gradient are adjusted dependent on resonant frequencies of substances present within the predetermined volume segment in order, starting from the predetermined volume segment to shift an actual excitation volume segment excited by the RF excitation pulse toward the marked area, or to shift a saturation volume saturated by the RF excitation pulse away from the marked area. MR data are then acquired from the predetermined volume segment.

An MR Spectroscopy (MRS) system and approach is provided for diagnosing painful and non-painful discs in chronic, severe low back pain patients (DDD-MRS). A DDD-MRS pulse sequence generates and acquires DDD-MRS spectra within intervertebral disc nuclei for later signal processing & diagnostic analysis. An interfacing DDD-MRS signal processor receives output signals of the DDD-MRS spectra acquired and is configured to optimize signal-to-noise ratio (SNR) by an automated system that selectively conducts optimal channel selection, phase and frequency correction, and frame editing as appropriate for a given acquisition series. A diagnostic processor calculates a diagnostic value for the disc based upon a weighted factor set of criteria that uses MRS data extracted from the acquired and processed MRS spectra along regions associated with multiple chemicals that have been correlated to painful vs. non-painful discs. A diagnostic display provides a scaled, color coded legend and indication of results for each disc analyzed as an overlay onto a mid-sagittal T2-weighted MRI image of the lumbar spine for the patient being diagnosed. Clinical application of the embodiments provides a non-invasive, objective, pain-free, reliable approach for diagnosing painful vs. non-painful discs by simply extending and enhancing the utility of otherwise standard MRI exams of the lumbar spine.

Systems and methods for acquiring magnetic resonance images that accurately depict vascular calcifications, or other objects composed of magnetic susceptibility-shifted substances, in a subject are provided. The images are generally acquired using a pulse sequence that is designed to reduce physiological motion-induced artifacts and to mitigate chemical-shift artifacts from water-fat boundaries. Advantageously, the MRI technique described here suppresses chemical-shift artifacts without significantly reducing the signal intensity from fatty tissues, and thereby allows for more reliable visualization of vascular calcifications.

At least a portion of a body (10) of a patient positioned in an examination volume of a MR device (1). A portion of the body (10) is subject to a calibration sequence including RF pulses and switched magnetic field gradients controlled in such a manner that a calibration signal data set is acquired by a multi-point Dixon technique at a first image resolution. Calibration parameters are derived from the calibration signal data set. The MR device (1) is controlled according to the derived calibration parameters. The portion of the body (10) is subject to an imaging sequence including RF pulses and switched magnetic field gradients controlled in such a manner that a diagnostic signal data set is acquired at a second image resolution which is higher than the first image resolution. A diagnostic MR image is reconstructed from the diagnostic signal data set.

At least a portion of a body (10) of a patient is positioned in an examination volume of a MR device (1). The portion of the body (10) is subject to a calibration sequence including RF pulses and switched magnetic field gradients controlled in such a manner that a calibration signal data set is acquired by a multi-point Dixon technique at a first image resolution. Calibration parameters are derived from the calibration signal data set. The portion of the body (10) is subject to an imaging sequence including RF pulses and switched magnetic field gradients controlled in such a manner that a diagnostic signal data set is acquired at a second image resolution which is higher than the first image resolution A diagnostic MR image is reconstructed from the diagnostic signal data set. The MR device (1) is operated according to the derived calibration parameters with fat saturation during acquisition of the diagnostic signal data set and/or during reconstruction of the diagnostic MR image.

In a method and apparatus for magnetic resonance imaging, a flip angle and/or inversion time of a spectrum suppression pulse is calculated according to a steady state condition of a longitudinal magnetization component of a spectrum composition suppressed by the spectrum suppression pulse and a zero crossing point condition of the longitudinal magnetization component. Raw magnetic resonance image data are acquired by applying a magnetic resonance imaging sequence that includes the spectrum suppression pulse provided with the flip angle and/or the inversion time.

Disclosed herein is a medical system (100, 300) comprising a memory (110) storing machine executable instructions (120). The medical system further comprises a computational system (104). Execution of the machine executable instructions causes the computational system to: receive (200) initial pulse sequence commands (122), wherein the initial pulse sequence commands are configured for controlling a magnetic resonance imaging system (302) to acquire k-space data (332) following a non-Cartesian k-space sampling pattern (604, 604), wherein the initial pulse sequence commands are configured for controlling the magnetic resonance imaging system to sample the non-Cartesian k-space sampling pattern by repeatedly sampling a Cartesian k-space sampling pattern (126) that is rotated for each acquisition, wherein the non-Cartesian k-space sampling pattern has an effective water-fat shift direction (606, 606); receive (202) a chosen water-fat shift direction (124); and construct (204) modified pulse sequence commands by rotating the non-Cartesian k-space sampling pattern such that the effective water-fat shift direction is aligned with the water-fat shift direction.

The disclosure discloses a chemical-shift-encoded imaging method and apparatus based on phase unwrapping, and a device. Comprises: performing phase conversion on the phasor candidate solution for the purpose of enabling a difference between a correct solution and an inverse decomposition solution of the phasor candidate solution to be within a set range, and on the basis of a phase unwrapping method, performing determination to obtain an intermediate phasor solution; determining a true phase of the intermediate phasor solution, and converting the true phase to a phasor candidate solution space to determine a target phasor solution; and on the basis of the target phasor solution, determining a first chemical component signal and a second chemical component signal, and on the basis of the first chemical component signal and/or the second chemical component signal, performing chemical-shift-encoded imaging.