Abstract: A magnetic resonance imaging method and imaging device are disclosed. The magnetic resonance imaging method includes dividing the current slab of an imaging region into an initial number of detection sub-slabs, and expanding the encoded thickness of each detection sub-slab according to a predetermined initial expansion factor, subjecting each expanded detection sub-slab to deformation detection using the first fast spin echo sequence, and determining the position of each imaging sub-slab of the current slab and an expansion factor corresponding to each imaging sub-slab, wherein the readout gradient of the first fast spin echo sequence is applied in the direction of the slice selection gradient, expanding the encoded thickness of each imaging sub-slab of the current slab of the imaging region on the basis of the determined position of each imaging sub-slab and the corresponding expansion factor, and performing an imaging scan of each expanded imaging sub-slab using a second fast spin echo sequence.

Abstract: Acquisition of magnetic resonance (MR) data in a predetermined three-dimensional volume segment of an examination subject with an MR apparatus proceeds by the volume segment being excited with an RF excitation pulse, and repeated, temporally sequential implementation of the following in order to respectively read out an echo train: Switch a refocusing pulse. Switch a first phase coding gradient in a first direction and a second phase coding gradient in a second direction. Switch an additional magnetic field gradient for spatial coding in a third direction which is perpendicular to the first direction and the second direction, wherein the MR data of a k-space line are read out while the additional magnetic field gradient is switched. Every k-space line corresponds to a line of k-space that corresponds to the volume segment. At least one k-space line is read out repeatedly in a middle segment of k-space.

Abstract: In an embodiment, a method is disclosed which includes: carrying out interpolation by using a slice away from a slab boundary, and substituting a slice having slab boundary artifacts existing in the slab boundary, to obtain an interpolated image; carrying out Fourier transform on the interpolated image to generate first K-space data; carrying out Fourier transform on the original image to generate second K-space data; merging the first K-space data with the second K-space data, wherein the weight of the first K-space data is greater than that of the second K-space data in the middle of the K-space, and the weight of the second K-space data is greater than that of the first K-space data at the edge of the K-space; and carrying out inverse Fourier transform on the merged K-space data.

Abstract: A three-dimensional turbo spin echo imaging method of applying, within a repetition time TR, N groups of pulses to respectively scan N slabs in succession, with each group including one excitation pulse and more than one refocusing pulse, wherein N is a positive integer greater than 1, is improved by applying a first slice selection gradient at the same time as applying each said excitation pulse, and applying a second slice selection gradient at the same time as applying each said refocusing pulse, and applying a phase encoding gradient after having applied each refocusing pulse, then applying a frequency encoding gradient and acquiring scan signals during the duration of the frequency encoding gradient. An image according to the scan signals is reconstructed.

Abstract: A magnetic resonance imaging method and imaging device are disclosed. The magnetic resonance imaging method includes dividing the current slab of an imaging region into an initial number of detection sub-slabs, and expanding the encoded thickness of each detection sub-slab according to a predetermined initial expansion factor, subjecting each expanded detection sub-slab to deformation detection using the first fast spin echo sequence, and determining the position of each imaging sub-slab of the current slab and an expansion factor corresponding to each imaging sub-slab, wherein the readout gradient of the first fast spin echo sequence is applied in the direction of the slice selection gradient, expanding the encoded thickness of each imaging sub-slab of the current slab of the imaging region on the basis of the determined position of each imaging sub-slab and the corresponding expansion factor, and performing an imaging scan of each expanded imaging sub-slab using a second fast spin echo sequence.

Abstract: Acquisition of magnetic resonance (MR) data in a predetermined three-dimensional volume segment of an examination subject with an MR apparatus proceeds by the volume segment being excited with an RF excitation pulse, and repeated, temporally sequential implementation of the following in order to respectively read out an echo train: Switch a refocusing pulse. Switch a first phase coding gradient in a first direction and a second phase coding gradient in a second direction. Switch an additional magnetic field gradient for spatial coding in a third direction which is perpendicular to the first direction and the second direction, wherein the MR data of a k-space line are read out while the additional magnetic field gradient is switched. Every k-space line corresponds to a line of k-space that corresponds to the volume segment. At least one k-space line is read out repeatedly in a middle segment of k-space.

Abstract: In a method and device for side-band suppression, a positive eddy current correction factor and negative eddy current correction factor are determined and scanning N/2 times by a positive gradient takes place, and the positive gradient scanning signal is collected during each scan. Scanning N/2 times by a negative gradient also takes place, and the negative gradient scanning signal is collected during each scan. N is an even number. An eddy current correction of the N/2 positive gradient scanning signals collected according to the positive eddy current correction factor is performed as an eddy current correction of the N/2 negative gradient scanning signals collected according to the negative eddy current correction factor. The side-band suppressed spectrum signal according to the N/2 positive gradient scanning signals that have undergone the eddy current correction is calculated, as is the N/2 negative gradient scanning signals that have undergone the eddy current correction.

Abstract: In an embodiment, a method is disclosed which includes: carrying out interpolation by using a slice away from a slab boundary, and substituting a slice having slab boundary artifacts existing in the slab boundary, to obtain an interpolated image; carrying out Fourier transform on the interpolated image to generate first K-space data; carrying out Fourier transform on the original image to generate second K-space data; merging the first K-space data with the second K-space data, wherein the weight of the first K-space data is greater than that of the second K-space data in the middle of the K-space, and the weight of the second K-space data is greater than that of the first K-space data at the edge of the K-space; and carrying out inverse Fourier transform on the merged K-space data.

Abstract: In a method and device for correcting distortion in MRI, k-space data are acquired in a number of data readout directions, the data are converted into a number of images, and a corresponding pixel shift map is generated for each image. The geometric distortion in the corresponding image is corrected according to the pixel shift map, and then all geometric distortion-corrected images are combined. Since movement distortion normally exists in the data readout direction, collecting the k-space data from a number of data readout directions can effectively correct movement distortion. Moreover, correcting the geometric distortion for the images converted from data acquired in a number of data readout directions according to the pixel shift map can reduce the geometric distortion of the final image generated from combination of images. The method and device correct not only movement distortion of MRI images, but also geometric distortion of MRI images.

Abstract: In a method and apparatus for correcting distortion during magnetic resonance imaging k space data in a number of readout encoding directions, sampling points on the phase encoding lines are primarily in low frequency regions of k space and the number of such sampling points is less than that of all sampling points. A view angle tilting compensation gradient is superimposed on the axis of a layer selection gradient. The k space data acquired from the number of directions are then combined.

Abstract: A three-dimensional turbo spin echo imaging method of applying, within a repetition time TR, N groups of pulses to respectively scan N slabs in succession, with each group including one excitation pulse and more than one refocusing pulse, wherein N is a positive integer greater than 1, is improved by applying a first slice selection gradient at the same time as applying each said excitation pulse, and applying a second slice selection gradient at the same time as applying each said refocusing pulse, and applying a phase encoding gradient after having applied each refocusing pulse, then applying a frequency encoding gradient and acquiring scan signals during the duration of the frequency encoding gradient. An image according to the scan signals is reconstructed.

Abstract: In a method and device for side-band suppression, a positive eddy current correction factor and negative eddy current correction factor are determined and scanning N/2 times by a positive gradient takes place, and the positive gradient scanning signal is collected during each scan. Scanning N/2 times by a negative gradient also takes place, and the negative gradient scanning signal is collected during each scan. N is an even number. An eddy current correction of the N/2 positive gradient scanning signals collected according to the positive eddy current correction factor is performed as an eddy current correction of the N/2 negative gradient scanning signals collected according to the negative eddy current correction factor. The side-band suppressed spectrum signal according to the N/2 positive gradient scanning signals that have undergone the eddy current correction is calculated, as is the N/2 negative gradient scanning signals that have undergone the eddy current correction.

Abstract: In a method and device for suppressing residual motion artifacts, k-space is divided into a snapshot segment, an alternate sampling segment and a high frequency segment in a phase encoding direction; then phase encoding lines are respectively sampled within each of the segments; and a magnetic resonance image is reconstructed according to the phase encoding lines within k-space.

Abstract: In a method and device for suppressing residual motion artifacts, k-space is divided into a snapshot segment, an alternate sampling segment and a high frequency segment in a phase encoding direction; then phase encoding lines are respectively sampled within each of the segments; and a magnetic resonance image is reconstructed according to the phase encoding lines within k-space.

Abstract: In a method and device for correcting distortion in MRI, k-space data are acquired in a number of data readout directions, the data are converted into a number of images, and a corresponding pixel shift map is generated for each image. The geometric distortion in the corresponding image is corrected according to the pixel shift map, and then all geometric distortion-corrected images are combined. Since movement distortion normally exists in the data readout direction, collecting the k-space data from a number of data readout directions can effectively correct movement distortion. Moreover, correcting the geometric distortion for the images converted from data acquired in a number of data readout directions according to the pixel shift map can reduce the geometric distortion of the final image generated from combination of images. The method and device correct not only movement distortion of MRI images, but also geometric distortion of MRI images.

Abstract: In a method and apparatus for correcting distortion during magnetic resonance imaging k space data in a number of readout encoding directions, wherein the sampling points on the phase encoding lines are concentrated in low frequency regions and their number is less than that of full sampling points. A view angle tilting compensation gradient is superimposed on the axis of a layer selection gradient. The k space data acquired from the number of directions are then combined. Due to the fact that the superimposition of the view angle tilting compensation gradient on the axis of the slice selection gradient can effectively correct geometric distortions, and at the same time the resolution in phase encoding lines is relatively high, low resolution contents are provided only in readout encoding directions, so the degree of blurring in the final image is substantially reduced. Furthermore, by acquiring the k space data in a number of readout directions the sensitivity to motion artifacts can effectively be reduced.

Abstract: In a method and apparatus for accelerating MR temperature imaging used in MR-monitored high intensity focused ultrasound (HIFU) therapy, temperature changes are determined at the focus of the ultrasound during MR temperature imaging; determining the ideal acceleration rate needed for data sampling according to the temperature changes at said focus is determined, the variable-density (VD) data sampling in k-space is adjusted according to the determined ideal acceleration rate, and the data obtained from sampling are reconstructed to form an image. The capability of accelerating MR temperature imaging with both good temporal resolution and good spatial resolution is improved by determining the acceleration rate according to temperature changes at the ultrasound focus and by adjusting the VD data sampling of k-space and thereby the benefits of good flexibility, feasibility and stability are achieved.

Abstract: In a method and apparatus for accelerating MR temperature imaging used in MR-monitored high intensity focused ultrasound (HIFU) therapy, temperature changes are determined at the focus of the ultrasound during MR temperature imaging; determining the ideal acceleration rate needed for data sampling according to the temperature changes at said focus is determined, the variable-density (VD) data sampling in k-space is adjusted according to the determined ideal acceleration rate, and the data obtained from sampling are reconstructed to form an image. The capability of accelerating MR temperature imaging with both good temporal resolution and good spatial resolution is improved by determining the acceleration rate according to temperature changes at the ultrasound focus and by adjusting the VD data sampling of k-space and thereby the benefits of good flexibility, feasibility and stability are achieved.