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: For magnetic resonance imaging (MRI), a dynamic frequency drift correction method for binomial water excitation method includes collecting the reference one-dimensional navigation signal by an MRI device; acquiring one current one-dimensional navigation signal after scanning N images, wherein N is a positive integer; calculating the frequency drift according to the reference one-dimensional navigation signal and the current one-dimensional navigation signal; calculating and setting the initial phase of the next radio frequency signal by the MRI device according to the frequency drift.

Abstract: In a method and an apparatus for making a distinction in a magnetic resonance imaging water-fat image, three echoes are acquired without phase encoding as a reference scan, a reference water-fat image projection is calculated in the phase encoding direction using the reference scan, a complete water-fat image projection is calculated in the phase encoding direction according to a water image and a fat image obtained by a three-point Dixon method, a correlation between the reference water-fat image projection and the complete water-fat image projection is calculated to obtain at least two correlated values, and the maximum correlated value is acquired therefrom, so as to determine the type of said image calculated by using the three-point Dixon method.

Abstract: In a method and system for echo planar imaging, after having applied a radiofrequency pulse and a slice selection gradient, continuous readout gradients alternating between positive and negative are applied and a phase encoding gradient is applied before starting each readout gradient. A slice selection gradient is applied at the same time as applying the phase encoding gradient. Scanning signals are collected during the duration of the readout gradients. Image reconstruction is implemented based on the scanning signals to obtain a scanned image.

Abstract: A magnetic resonance imaging (MRI) water-fat separation method includes acquiring in-phase image raw measurement data and out-of-phase image raw measurement data with an MRI device, reconstructing an in-phase image and an out-of-phase image according to a system matrix and the raw measurement data using the penalty function regularized iterative reconstruction method, and calculating water and fat images according to the in-phase image and the out-of-phase image. The use of the penalty function regularized iterative method eliminates the need for k-space raw measurement data with a 100% sampling rate, thereby reducing the MRI scan time, shortening the entire imaging time, and improving the efficiency of the MRI device.

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.

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 method and an apparatus for making a distinction in a magnetic resonance imaging water-fat image, three echoes are acquired without phase encoding as a reference scan, a reference water-fat image projection is calculated in the phase encoding direction using the reference scan, a complete water-fat image projection is calculated in the phase encoding direction according to a water image and a fat image obtained by a three-point Dixon method, a correlation between the reference water-fat image projection and the complete water-fat image projection is calculated to obtain at least two correlated values, and the maximum correlated value is acquired therefrom, so as to determine the type of said image calculated by using the three-point Dixon method.

Abstract: A magnetic resonance imaging method for achieving water-fat separation; the method includes utilizing BLADE trajectories to collect the original data of one in-phase image and the original data of two out-of-phase images; reconstructing the in-phase image on the basis of the original data of the in-phase image, and utilizing the original data of the in-phase image to perform phase correction on the original data of the out-of-phase images, and reconstructing the out-of-phase images; and calculating the images of water and fat on the basis of the in-phase image and the out-of-phase images. Since the BLADE trajectory is used to acquire the k-space data, it provides the advantages that the BLADE trajectories are insensitive to the motion and pulsation of a rigid body, reduce the degree of sensitivity to motion artifacts, and also improve the images' signal-to-noise ratio.

Abstract: For magnetic resonance imaging (MRI), a dynamic frequency drift correction method for binomial water excitation method includes collecting the reference one-dimensional navigation signal by an MRI device; acquiring one current one-dimensional navigation signal after scanning N images, wherein N is a positive integer; calculating the frequency drift according to the reference one-dimensional navigation signal and the current one-dimensional navigation signal; calculating and setting the initial phase of the next radio frequency signal by the MRI device according to the frequency drift.

Abstract: A magnetic resonance imaging (MRI) water-fat separation method includes acquiring in-phase image raw measurement data and out-of-phase image raw measurement data with an MRI device, reconstructing an in-phase image and an out-of-phase image according to a system matrix and the raw measurement data using the penalty function regularized iterative reconstruction method, and calculating water and fat images according to the in-phase image and the out-of-phase image. The use of the penalty function regularized iterative method eliminates the need for k-space raw measurement data with a 100% sampling rate, thereby reducing the MRI scan time, shortening the entire imaging time, and improving the efficiency of the MRI device.

Abstract: In a method for reconstructing an image from an echo planar imaging sequence, the echo planar imaging sequence is used to obtain multi-line k-space data from a subject and the multi-line k-space data are divided into odd line data and even line data. Fourier transform is performed on the odd line data and on the even line data separately to obtain corresponding amplitude images. The amplitude images obtained is this manner are added to produce the final image. The method effectively eliminates N/2 artifacts by over-sampling in the phase direction. By image reconstruction being carried out separately on the odd line data and even line data of k-space data and then integrating the images, the method effectively avoids the problem of the image signal loss caused by the mutual cancellation of the odd line data and even line data.

Abstract: In a method and system for echo planar imaging, after having applied a radiofrequency pulse and a slice selection gradient, continuous readout gradients alternating between positive and negative are applied and a phase encoding gradient is applied before starting each readout gradient. A slice selection gradient is applied at the same time as applying the phase encoding gradient. Scanning signals are collected during the duration of the readout gradients. Image reconstruction is implemented based on the scanning signals to obtain a scanned image.

Abstract: In a multi-channel magnetic resonance imaging reconstruction method for water-fat separation, one in-phase image and two opposed-phase images are acquired with multiple reception coils in respective channels. The sensitivity distribution of the coils of the respective channels is calculated. The images of respective channels are merged dependent on the sensitivity distribution. A phase difference between the two opposed-phase images is calculated. At lease one characteristic region of the in-phase image is detected, which is used as a criterion for phase correction. The phases of the opposed-phase images are corrected and images of water and fat are calculated. The method provides stable and reliable imaging, has a short reconstruction time and also solves the problem that images of water and fat may be exchanged.

Abstract: In a method for reconstructing an image from an echo planar imaging sequence, the echo planar imaging sequence is used to obtain multi-line k-space data from a subject and the multi-line k-space data are divided into odd line data and even line data. Fourier transform is performed on the odd line data and on the even line data separately to obtain corresponding amplitude images. The amplitude images obtained is this manner are added to produce the final image. The method effectively eliminates N/2 artifacts by over-sampling in the phase direction. By image reconstruction being carried out separately on the odd line data and even line data of k-space data and then integrating the images, the method effectively avoids the problem of the image signal loss caused by the mutual cancellation of the odd line data and even line data.