G01R33/5617

METHOD AND APPARATUS FOR FREQUENCY DRIFT CORRECTION OF MAGNETIC RESONANCE CEST IMAGING, AND MEDIUM AND IMAGING DEVICE
20220381866 · 2022-12-01 ·

Disclosed is a method and apparatus for frequency drift correction of magnetic resonance CEST imaging, and a medium and an imaging device. The method comprises the following steps: firstly, in the frequency drift correction module, exciting a target slice by using a small flip-angle radio-frequency pulse, and acquiring a single line of free induction decay signals or two lines of non-phase encoding gradient echo signals; secondly, respectively calculating a value of the main magnetic field frequency drift according to phase information and an acquisition time of the single line of free induction decay signals or the two lines of non-phase encoding gradient echo signals; then adjusting the center frequency of the magnetic resonance device in real time according to the calculated value of the main magnetic field frequency drift, and achieving the real-time correction of main magnetic field frequency drift; and finally, performing CEST imaging.

METHODS AND SYSTEMS FOR SPIN-ECHO TRAIN IMAGING USING SPIRAL RINGS WITH RETRACED TRAJECTORIES

Methods, computing devices, and magnetic resonance imaging systems that improve image quality in turbo spiral echo (TSE) imaging are disclosed. With this technology, a TSE pulse sequence is generated that includes a series of radio frequency (RF) refocusing pulses to produce a corresponding series of nuclear magnetic resonance (NMR) spin echo signals. A gradient waveform including a plurality of segments is generated. The plurality of segments collectively comprise a spiral ring retraced in-out trajectory. During an interval adjacent to each of the series of RF refocusing pulses, a first gradient pulse is generated according to the gradient waveform. The first gradient pulses encode the NMR spin echo signals. An image is then constructed from digitized samples of the NMR spin echo signals obtained based at least in part on the encoding.

MAGNETIC RESONANCE IMAGING APPARATUS

A magnetic resonance imaging apparatus according to an embodiment includes processing circuitry. The processing circuitry sets a pulse sequence to collect plural echo signals by application of a refocusing pulse more than once after application of an excitation pulse once, and collects data on plural slices that are parallel to each other by executing the pulse sequence more than once. The processing circuitry sets the pulse sequence such that a slice thickness for the refocusing pulse becomes larger than a slice thickness for the excitation pulse, and collects the data on the plural slices by executing the pulse sequence without consecutively collecting data on adjacent ones of the plural slices.

Adaptive Reconstruction of MR Data

An adaptive reconstruction of MR data, including acquired MR data of a core region having core segments and simulated MR data of a peripheral region. The method includes ascertaining a peripheral signal based on the MR data of the peripheral region, determining a scaling factor for each core segment by taking into account the peripheral signal and a mean signal intensity of the MR data for the respective core segment, scaling the MR data of the core region by taking into account the MR data of each core segment and that of the scaling factor corresponding to the respective core segment, generating filtered MR data by combining the scaled MR data of the core region with the MR data of the peripheral region, and reconstructing image data from the filtered MR data.

METHODS AND SYSTEMS FOR MAXWELL COMPENSATION FOR SPIN-ECHO TRAIN IMAGING

Methods, computing devices, and MRI systems that reduce artifacts produced by Maxwell gradient terms in TSE imaging using non-rectilinear trajectories are disclosed. With this technology, a RF excitation pulse is generated to produce transverse magnetization that generates a NMR signal and a series of RF refocusing pulses to produce a corresponding series of NMR spin-echo signals. An original encoding gradient waveform comprising a non-rectilinear trajectory is modified by adjusting a portion of the original encoding gradient waveform or introducing a zero zeroth-moment waveform segment at end(s) of the original encoding gradient waveform. During an interval adjacent to each of the series of RF refocusing pulses a first gradient pulse is generated. At least one of the first gradient pulses is generated according to the modified gradient waveform. An image is constructed from generated digitized samples of the NMR spin-echo signals obtained.

Systems and methods for separable motion estimation and correction using rapid three-dimensional (3D) volumetric scout acquisition

In a method and system for reducing motion artifacts in magnetic resonance image data, a scout scan (e.g. a three-dimensional (3D) scout scan) of the region of the patient is performed, a magnetic resonance (MR) measurement of the region of the patient is performed to acquire two-dimensional (2D) MR image data of the region of the patient, and motion correction is performed on the acquired 2D MR image data based on the scout scan to generate corrected MR image data. The motion correction technique advantageously reduces an influence of a patient motion on the magnetic resonance image data.

T1-weighted turbo-spin-echo MRI sequence for producing high quality dark blood images at high heart rates
11604244 · 2023-03-14 · ·

A T1-weighted turbo-spin-echo magnetic resonance imaging system configured to capture data associated with a subject's heart during a time period and produce MR images has a dark-blood preparation module, a data capture module, and an image reconstruction module. The dark-blood preparation module performs dark-blood preparation through double inversion during some, but not all of the heartbeats within the time period. The data capture module configured performs data readouts to capture imaging data of an imaging slice during every heartbeat in which dark-blood preparation is performed. The data capture module also performs a steady state maintenance step during every heartbeat in which dark-blood preparation is not performed in order to maintain maximum T1-weighting. The image reconstruction module configured to reconstruct a T1-weighted image based on the imaging data.

Actuating a Magnetic Resonance Device with Compensated Maxwell Phase
20230072449 · 2023-03-09 · ·

A method for actuating a magnetic resonance device according to an MR control sequence, wherein the MR control sequence includes a bipolar gradient pulse between an excitation pulse and a first refocusing pulse, and the bipolar gradient pulse induces a defined Maxwell phase and generates a dephasing gradient moment for a readout gradient.

Minimization of effects of concomitant fields in multi echo imaging

The present disclosure relates to operating an MR system in which MR signals of an object under examination are acquired in an examining region using a multi echo imaging sequence, in which an RF excitation pulse and a plurality of RF refocusing pulses are applied. The techniques include determining a first accumulated phase of a magnetization in the object under examination. Then, a second accumulated phase of the magnetization in the object under examination is determined due to concomitant magnetic fields occurring between a second pair of consecutive RF pulses. Finally, it is determined whether a deviation from the predefined relationship is larger than a threshold and, if this is the case, a measure is applied in view of the fact that the deviation is larger than the threshold.

Magnetic resonance imaging apparatus, and program
11598835 · 2023-03-07 · ·

To provide a technique with which a FLAIR image and a T1-weighted image can be acquired in a short scan time, a magnetic resonance imaging apparatus comprises: an RF driver unit 121 for driving an RF coil unit 103; a gradient coil driver unit 122 for driving a gradient coil unit 102; and a controller unit 124 connected to the RF coil driver unit 121 and gradient coil driver unit 122, for controlling them so that an imaging sequence ISc having a duration of 1TR for generating echoes from a body part being imaged is repetitively executed, where the imaging sequence ISc has a first sequence part SQ1 including an inversion pulse 11 and an FSE sequence 12, and a second sequence part SQ2 including an inversion pulse 21 and a GRE sequence 22.