Abstract: The disclosure relates to techniques for triggering magnetic resonance data acquisition. The techniques include detecting a respiration direction of a respiration signal of an acquisition subject, predicting in real time an amplitude peak value of an expiration signal in the current respiration period according to the real-time respiration signal of the acquisition subject, multiplying the amplitude peak value by a preset coefficient, and using the product as a trigger point threshold of the current respiration period. When it is determined that an expiration stage of the current respiration period is starting, the techniques also include calculating in real time or periodically the absolute value of the difference between the amplitude of the current expiration signal and the trigger point threshold currently calculated, and if the absolute value of the difference is less than a preset difference threshold, then triggering MR data acquisition.

Abstract: The present disclosure is directed to MRI techniques. The techniques include occupying a central region of a first k-space with full sampling along a Cartesian trajectory, occupying a peripheral region of the first k-space with undersampling along a non-Cartesian trajectory; acquiring sensitivity distribution information of receiving coils; based on a sensitivity distribution chart, merging the Cartesian data of the central region according to multiple channels to obtain a third k-space; based on the sensitivity distribution chart, applying parallel imaging and compressed sensing to the undersampled non-Cartesian trajectory to reconstruct an image, obtaining a second k-space by transformation, and when the second k-space and third k-space are synthesized, using a central region of the second k-space to replace the third k-space of a corresponding region to obtain a k-space suitable for image reconstruction.

Abstract: In a MR water-fat image separation method and device, within one echo period, a first echo set under a first readout gradient polarity and a second echo set under a second readout gradient polarity are acquired. The first and second readout gradient polarities may be opposite, and echoes in the first echo set may be positionally one-to-one symmetric to echoes in the second echo set with respect to the echo center of the echo period. A first echo image set is obtained based on first echo set data acquired in each echo period, and a second echo image set is obtained based on second echo set data acquired in each echo period. Using the first and second echo image sets, a Dixon water-fat separation calculation is performed to obtain a water image and a fat image. The method and device can advantageously increase acquisition efficiency and the signal-to-noise ratio.

Abstract: The present disclosure is directed to MRI techniques. The techniques include occupying a central region of a first k-space with full sampling along a Cartesian trajectory, occupying a peripheral region of the first k-space with undersampling along a non-Cartesian trajectory; acquiring sensitivity distribution information of receiving coils; based on a sensitivity distribution chart, merging the Cartesian data of the central region according to multiple channels to obtain a third k-space; based on the sensitivity distribution chart, applying parallel imaging and compressed sensing to the undersampled non-Cartesian trajectory to reconstruct an image, obtaining a second k-space by transformation, and when the second k-space and third k-space are synthesized, using a central region of the second k-space to replace the third k-space of a corresponding region to obtain a k-space suitable for image reconstruction.

Abstract: In a MR water-fat image separation method and device, within one echo period, a first echo set under a first readout gradient polarity and a second echo set under a second readout gradient polarity are acquired. The first and second readout gradient polarities may be opposite, and echoes in the first echo set may be positionally one-to-one symmetric to echoes in the second echo set with respect to the echo center of the echo period. A first echo image set is obtained based on first echo set data acquired in each echo period, and a second echo image set is obtained based on second echo set data acquired in each echo period. Using the first and second echo image sets, a Dixon water-fat separation calculation is performed to obtain a water image and a fat image. The method and device can advantageously increase acquisition efficiency and the signal-to-noise ratio.

Abstract: In a method for correcting the interference in respiratory navigation, transmitting, during magnetic resonance scanning, a respiratory signal generated by a radio frequency signal generator to a human body; acquiring, as a measured respiratory signal, a respiratory signal passing through the human body and acquired in a local coil, wherein the measured respiratory signal is constituted by a real respiratory signal and an interference signal; determining, according to a respiratory signal coil sensitivity of the real respiratory signal and an interference signal coil sensitivity of the interference signal, a signal relation that is satisfied by the real respiratory signal, the interference signal and the measured respiratory signal; and calculating the signal relation to obtain the real respiratory signal.

Abstract: The present application describes techniques for determining and eliminating a time delay between a radio frequency pulse and a layer selection gradient in a magnetic resonance device. The techniques for determining and eliminating the time delay direct include measuring the time delay between the layer selection gradient and the radio frequency pulse by using phase information. This technique is more sensitive and accurate than existing methods that use signal or artifact strength.

Abstract: The disclosure relates to techniques for triggering magnetic resonance data acquisition. The techniques include detecting a respiration direction of a respiration signal of an acquisition subject, predicting in real time an amplitude peak value of an expiration signal in the current respiration period according to the real-time respiration signal of the acquisition subject, multiplying the amplitude peak value by a preset coefficient, and using the product as a trigger point threshold of the current respiration period. When it is determined that an expiration stage of the current respiration period is starting, the techniques also include calculating in real time or periodically the absolute value of the difference between the amplitude of the current expiration signal and the trigger point threshold currently calculated, and if the absolute value of the difference is less than a preset difference threshold, then triggering MR data acquisition.

Abstract: A method and a magnetic resonance imaging device, and a corresponding computer readable storage medium. The method includes acquiring a distortion function describing a frequency dependence of an amplitude or phase of an MR-signal received by a receiver part of the MRI-device, Fourier transforming K-space data acquired using this receiver part to image space data, generating compensated image space data by compensating for the frequency dependence by dividing the image space data or image space data derived therefrom in image space by the distortion function, and providing the MR-image as the compensated image space data or reconstructed therefrom.

Abstract: In a method, apparatus and storage medium for filling a k-space trajectory in magnetic resonance (MR) imaging, a blank window, following an RF excitation pulse, is set in an arbitrary spatial encoding direction, and a first MR signal is acquired in this blank window, to obtain the phase of the first MR signal. A gradient field is activated outside the blank window and a second MR signal is acquired to obtain the phase of the second MR signal. This first and second MR signals are entered into k-space along first k-space and second k-space trajectories that are respectively based on the phase of the first MR signal and the phase of the second MR signal. A calibrated k-space trajectory in the spatial encoding direction is determined based on the first and second k-space trajectories.

Abstract: The present disclosure provides techniques for determining a respiration phase by extracting a distance characteristic value, a score characteristic value, and an area characteristic value from the respiration signal, wherein the distance characteristic value, the score characteristic value and the area characteristic value are used to indicate waveform variation between two adjacent waveforms in the respiration signal. The techniques include training a respiration signal model according to the distance characteristic value, the score characteristic value, and the area characteristic value to determine the respiration phase of the respiration signal using the respiration signal model.

Abstract: In a method for correcting the interference in respiratory navigation, transmitting, during magnetic resonance scanning, a respiratory signal generated by a radio frequency signal generator to a human body; acquiring, as a measured respiratory signal, a respiratory signal passing through the human body and acquired in a local coil, wherein the measured respiratory signal is constituted by a real respiratory signal and an interference signal; determining, according to a respiratory signal coil sensitivity of the real respiratory signal and an interference signal coil sensitivity of the interference signal, a signal relation that is satisfied by the real respiratory signal, the interference signal and the measured respiratory signal; and calculating the signal relation to obtain the real respiratory signal.

Abstract: The present disclosure related to techniques for determining and eliminating a time delay between a radio frequency pulse and a layer selection gradient in a magnetic resonance device. The techniques for determining and eliminating the time delay direct measures the time delay between the layer selection gradient and the radio frequency pulse by using phase information. This technique is more sensitive and accurate than existing methods that use signal or artifact strength.

Abstract: In a magnetic resonance imaging method, a first adjustment parameter is determined for presetting an initial contrast of a magnetic resonance image; a second adjustment parameter is determined for obtaining an optimized contrast of the magnetic resonance image and a specified data acquisition time of a blade artifact correction sequence; an optimized echo signal evolution curve is determined according to the first adjustment parameter and the second adjustment parameter; an actual variable flip angle train is calculated according to the optimized echo signal evolution curve; and the actual variable flip angle train is applied to a two-dimensional fast spin echo sequence, and the blade artifact correction sequence corresponding to the second adjustment parameter is used to acquire magnetic resonance signals and enable the magnetic resonance image to satisfy the optimized contrast.

Abstract: A method and a magnetic resonance imaging device, and a corresponding computer readable storage medium. The method includes acquiring a distortion function describing a frequency dependence of an amplitude or phase of an MR-signal received by a receiver part of the MRI-device, Fourier transforming K-space data acquired using this receiver part to image space data, generating compensated image space data by compensating for the frequency dependence by dividing the image space data or image space data derived therefrom in image space by the distortion function, and providing the MR-image as the compensated image space data or reconstructed therefrom.

Abstract: In a method, apparatus and storage medium for filling a k-space trajectory in magnetic resonance (MR) imaging, a blank window, following an RF excitation pulse, is set in an arbitrary spatial encoding direction, and a first MR signal is acquired in this blank window, to obtain the phase of the first MR signal. A gradient field is activated outside the blank window and a second MR signal is acquired to obtain the phase of the second MR signal. This first and second MR signals are entered into k-space along first k-space and second k-space trajectories that are respectively based on the phase of the first MR signal and the phase of the second MR signal. A calibrated k-space trajectory in the spatial encoding direction is determined based on the first and second k-space trajectories.

Abstract: An imaging apparatus and a positioning apparatus that include an imaging unit for imaging a detected part of a body to be detected; and a distance positioning unit having at least two signal positioning devices, i.e., a signal generator and a signal detector, wherein one signal positioning device is arranged at the detected part, the other signal positioning device is arranged at a position where a predetermined position relationship exists relative to the imaging unit. The position of the detected part in at least one direction in a three-dimensional space relative to the imaging unit is obtained according to a measured distance between the two signal positioning devices. The imaging apparatus and the positioning apparatus reduce pre-positioning imaging sequence workload, and the risk of radiation on the body to be detected is avoided.

Abstract: In a magnetic resonance angiography method and apparatus, a time-of-flight sequence is used to acquire and enter k-space data, and a magnetic resonance angiography image is reconstructed from the k-space data. The time-of-flight sequence includes at least one saturation radio frequency pulse and multiple excitation radio frequency pulses. At least two of the excitation radio frequency pulses directly follow the saturation radio frequency pulse, and part of the k-space data is collected after each of the excitation pulses. Scanning time can thus be decreased, scanning efficiency can be improved, the electromagnetic absorption ratio can be reduced, and a venous magnetic resonance signal is still suppressed.

Abstract: In a trajectory correction method and apparatus for k-space data points in magnetic resonance imaging, a magnetic resonance data acquisition unit is operated to execute a sampling sequence to obtain k-space to be corrected. Empirical points are selected used to divide k-space to be corrected into a central region and a peripheral region. The trajectories of the data points in the central region and the peripheral region are corrected and the sampling sequence is executed again, with the corrected trajectories, to obtain corrected k-space.

Abstract: In a magnetic resonance imaging method and apparatus for water/fat separation, a turbo spin echo BLADE (TSE BLADE) artifact correction sequence is executed to acquire original data for an in-phase image and original data for an opposite-phase image, and an in-phase image on the basis of the original data for the in-phase image and an opposite-phase image on the basis of the original data for the in-phase image and the original data for the opposite-phase image are reconstructed. Water and fat images are calculated on the basis of the reconstructed in-phase image and opposite-phase image. By using a TSE BLADE sequence to acquire k-space data, the advantage of the BLADE sequence of being insensitive to rigid body motion and pulsation is inherently present, thereby reducing sensitivity to motion artifacts while improving the image signal-to-noise ratio.