CN113808228A - Imaging echo phase correction method, imaging echo phase correction device, imaging system and storage medium - Google Patents
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Abstract
本发明实施例中公开了一种成像回波相位校正方法、装置、成像系统和存储介质。其中，方法包括：在每个重复周期中的成像回波后采集一导航回波；针对每个重复周期，将重复周期相邻的前一重复周期中采集的导航回波作为参考导航回波，并将重复周期中采集的导航回波作为当前导航回波，计算当前导航回波与参考导航回波之间的相位差，根据所述相位差、当前导航回波与参考导航回波之间的时间差以及参考导航回波的相位建立一对应所述当前重复周期的线性相位校正模型；针对当前重复周期内的每个成像回波，根据所述成像回波与参考导航回波之间的时间差，利用所述线性相位校正模型得到所述成像回波的校正相位。本发明实施例中的技术方案能够降低图像中的伪影。
Embodiments of the present invention disclose an imaging echo phase correction method, device, imaging system and storage medium. The method includes: collecting a navigation echo after the imaging echo in each repetition period; for each repetition period, using the navigation echo collected in the previous repetition period adjacent to the repetition period as a reference navigation echo, Taking the navigation echo collected in the repetition period as the current navigation echo, calculate the phase difference between the current navigation echo and the reference navigation echo, according to the phase difference, the current navigation echo and the reference navigation echo The time difference and the phase of the reference navigation echo establish a linear phase correction model corresponding to the current repetition period; for each imaging echo in the current repetition period, according to the time difference between the imaging echo and the reference navigation echo, The corrected phase of the imaging echo is obtained by using the linear phase correction model. The technical solutions in the embodiments of the present invention can reduce artifacts in images.
Description
Technical Field
The invention relates to the technical field of magnetic resonance imaging, in particular to an imaging echo phase correction method and device of a multi-echo data merging imaging sequence, a magnetic resonance imaging system and a computer readable storage medium.
Background
Magnetic Resonance Imaging (MRI) is a technique for imaging using a Magnetic resonance phenomenon. The principles of magnetic resonance imaging mainly include: the atomic nucleus containing odd number of protons, such as hydrogen atomic nucleus widely existing in human body, has a spin motion as if it is a small magnet, and the spin axes of the small magnets are not regular, if an external magnetic field is applied, the small magnets will be rearranged according to the magnetic lines of the external magnetic field, specifically, arranged in two directions parallel or antiparallel to the magnetic lines of the external magnetic field, the direction parallel to the magnetic lines of the external magnetic field is called positive longitudinal axis, the direction antiparallel to the magnetic lines of the external magnetic field is called negative longitudinal axis, the atomic nucleus has only longitudinal magnetization component, and the longitudinal magnetization component has both direction and amplitude. The magnetic resonance phenomenon is that nuclei in an external magnetic field are excited by Radio Frequency (RF) pulses of a specific Frequency, so that the spin axes of the nuclei deviate from the positive longitudinal axis or the negative longitudinal axis to generate resonance. After the spin axes of the excited nuclei are offset from the positive or negative longitudinal axis, the nuclei have a transverse magnetization component.
After the emission of the radio frequency pulse is stopped, the excited atomic nucleus emits an echo signal, absorbed energy is gradually released in the form of electromagnetic waves, the phase and the energy level of the electromagnetic waves are restored to the state before the excitation, and the image can be reconstructed by further processing the echo signal emitted by the atomic nucleus through space coding and the like. The above-mentioned process of recovering excited nuclei to a pre-excited state is called a relaxation process, and the time required for recovering to an equilibrium state is called a relaxation time.
MRI imaging includes images of various cross sections in a desired direction. k-space is the data space of each cross section, i.e. k-space data represents a set of raw data that can form an image. For example, after acquiring echo data of k-space by using a three-dimensional fast gradient echo sequence, the echo data is filled into a phase encoding k-space. By then performing a fourier transform on the k-space data, a desired image can be obtained.
After a plurality of Gradient Echo (GRE) pulse sequences are excited by a small angle pulse, only one Echo is acquired at a time by switching readout gradients, and the acquired Echo is filled on one coding line of k space. The intrinsic SNR of the images obtained for the GRE sequence is low, in particular the SNR of T2 xwi is lower. In order to achieve a certain SNR of the image, a narrow acquisition bandwidth is often used, the signal acquisition speed is slowed down, and T2 attenuation causes distortion of the echo shape and loss of image spatial resolution.
After a Multi-Echo Data merging Imaging (MEDIC) sequence is excited by a small angle pulse, a plurality of gradient echoes (usually 3-6) are acquired by utilizing the Multi-switching of a readout gradient field, the gradient echoes adopt the same phase coding, and finally the echoes are merged and filled on the same phase coding line of a k space, which is equivalent to the fact that the gradient Echo sequence for acquiring a single Echo is repeated for a plurality of times, so that the signal-to-noise ratio is improved to a great extent, the bandwidth can be increased, the acquisition speed is accelerated, the spatial resolution is improved, and the magnetic sensitivity artifact is reduced.
At present, T2 wii multi-echo data-merging imaging sequences are the most commonly used sequences for cervical spine imaging, because the use of unipolar readout gradients and multi-echo combinations are advantageous to avoid non-resonance effects and to produce high signal-to-noise ratios. However, during scanning, changes in the respiratory motion or respiratory induced field may cause phase errors between echoes, thereby reducing the signal-to-noise ratio of the image and possibly causing severe image artifacts.
Disclosure of Invention
In view of the above, embodiments of the present invention provide an imaging echo phase correction method based on a multi-echo data merged imaging sequence, and provide an imaging echo phase correction apparatus based on a multi-echo data merged imaging sequence, a magnetic resonance imaging system, and a computer readable storage medium, so as to improve a signal-to-noise ratio of an image and reduce image artifacts.
The imaging echo phase correction method based on the multi-echo data merging imaging sequence provided by the embodiment of the invention comprises the following steps: acquiring a navigation echo after an imaging echo in each repetition period when data acquisition is carried out based on a multi-echo data merging imaging sequence, wherein the navigation echo is a phase-free encoding gradient echo; aiming at a current repetition period in each repetition period, taking a navigation echo acquired in a previous repetition period adjacent to the current repetition period as a reference navigation echo, taking the navigation echo acquired in the current repetition period as a current navigation echo, calculating a phase difference between the current navigation echo and the reference navigation echo, and establishing a linear phase correction model corresponding to the current repetition period according to the phase difference, a time difference between the current navigation echo and the reference navigation echo and the phase of the reference navigation echo; and aiming at each imaging echo in the current repetition period, obtaining the correction phase of the imaging echo by using the linear phase correction model according to the time difference between the imaging echo and the reference navigation echo.
In one embodiment, the navigator echo is a half-wave or other incomplete echo.
In one embodiment, the navigator echo employs an acquisition bandwidth of a first width that is greater than an acquisition bandwidth width at which the imaging echo is acquired.
The imaging echo phase correction device based on the multi-echo data merging imaging sequence provided by the embodiment of the invention comprises: the echo acquisition unit is used for acquiring a navigation echo after an imaging echo in each repetition period when data acquisition is carried out based on a multi-echo data merging imaging sequence, wherein the navigation echo is a phase-free encoding gradient echo; the model establishing unit is used for taking the navigation echo acquired in the previous repetition period adjacent to the current repetition period as a reference navigation echo and taking the navigation echo acquired in the current repetition period as a current navigation echo for the current repetition period in each repetition period, calculating the phase difference between the current navigation echo and the reference navigation echo, and establishing a linear phase correction model corresponding to the current repetition period according to the phase difference, the time difference between the current navigation echo and the reference navigation echo and the phase of the reference navigation echo; and the phase determining unit is used for obtaining the correction phase of the imaging echo by utilizing the linear phase correction model according to the time difference between the imaging echo and the reference navigation echo aiming at each imaging echo in the current repetition period.
In one embodiment, the echo acquisition unit acquires a navigator echo of a half-wave or other incomplete echo.
In one embodiment, the echo acquisition unit acquires the navigator echo with an acquisition bandwidth of a first width, which is greater than an acquisition bandwidth width of acquiring the imaging echo.
The imaging echo phase correction device based on the multi-echo data merging imaging sequence provided by the embodiment of the invention comprises: at least one memory and at least one processor, wherein: the at least one memory is for storing a computer program; the at least one processor is configured to invoke a computer program stored in the at least one memory to perform the method for imaging echo phase correction based on multi-echo data combined imaging sequence as described in any of the above.
The magnetic resonance imaging system provided by the embodiment of the invention comprises the imaging echo phase correction device based on the multi-echo data combination imaging sequence.
A computer-readable storage medium having a computer program stored thereon, the computer program being proposed in an embodiment of the present invention; the computer program can be executed by a processor and implements the method for imaging echo phase correction based on multi-echo data combined imaging sequence as described in any one of the above.
It can be seen from the above solution that in the embodiment of the present invention, a navigation echo is acquired after the imaging echo of each repetition period, and a piecewise linear phase correction model is established based on the phase difference and the time difference between adjacent navigation echoes, so that for each imaging echo in each repetition period, the corrected phase of the imaging echo is obtained by using the piecewise linear phase correction model according to the time difference between the imaging echo and the reference navigation echo. Thus, image artifacts caused by imaging echo phase errors caused directly or indirectly by respiratory motion can be eliminated.
In addition, the acquisition speed can be increased by acquiring the navigation echo of the incomplete wave such as the half wave or the like or acquiring the navigation echo by adopting a wider acquisition bandwidth.
Drawings
The foregoing and other features and advantages of the invention will become more apparent to those skilled in the art to which the invention relates upon consideration of the following detailed description of a preferred embodiment of the invention with reference to the accompanying drawings, in which:
fig. 1 is an exemplary flowchart of an imaging echo phase correction method based on a multi-echo data combination imaging sequence according to an embodiment of the present invention.
Fig. 2 is a schematic diagram of a data acquisition sequence for magnetic resonance imaging based on the MEDIC sequence in an example of the present invention.
Fig. 3A and 3B are schematic diagrams of a segmented linear phase correction model according to an embodiment of the invention.
Fig. 4 is an exemplary structural diagram of an imaging echo phase correction device based on a multi-echo data combination imaging sequence according to an embodiment of the present invention.
Fig. 5 is an exemplary structural diagram of another imaging echo phase correction device based on a multi-echo data combination imaging sequence in an embodiment of the present invention.
Fig. 6 and 7 are schematic diagrams illustrating a comparison between a C-spine image (second row) obtained by a magnetic resonance imaging method according to an example of the present invention, which uses the imaging echo phase correction method of the multi-echo data combined imaging sequence according to the embodiment of the present invention, and a C-spine image (first row) obtained by a conventional magnetic resonance imaging method.
Wherein the reference numbers are as follows:
| reference numerals | Means of |
| RF | Radio frequency pulse |
| SL | Level selection gradient |
| PE | Phase encoding gradient |
| RO | Frequency encoding/readout gradient |
| ADC | Echo data |
| E1、E2、E3 | Imaging echo |
| Nr、Nc | Navigation echo |
| S22、S24、S26、S51～S58 | Step (ii) of |
| 401 | Echo acquisition unit |
| 402 | Model building unit |
| 403 | Phase determination unit |
| 71 | Memory device |
| 72 | Processor with a memory having a plurality of memory cells |
Detailed Description
In the embodiment of the invention, when data acquisition is carried out based on a multi-echo data combination imaging sequence, an echo without a phase encoding gradient can be acquired in each repetition period, and the echo is not used for imaging but only used for phase correction navigation. Therefore, in order to improve the signal-to-noise ratio of an image and reduce image artifacts, it is considered to acquire a navigator echo acquired after an imaging echo in each repetition period when data acquisition is performed based on a multi-echo data combination imaging sequence, then establish a segmented linear phase correction model based on every two neighboring navigator echoes, and perform phase correction on the imaging echo located on each segment based on the segmented linear phase correction model.
Fig. 1 is an exemplary flowchart of an imaging echo phase correction method based on a multi-echo data combination imaging sequence according to an embodiment of the present invention. As shown in fig. 1, the method may include the steps of:
Fig. 2 is a schematic diagram of a data acquisition sequence for magnetic resonance imaging based on the MEDIC sequence in an example of the present invention. As shown in fig. 2, after one radio frequency pulse (RF) excitation, the readout gradient (RO) field is switched multiple times based on the current slice selection gradient (SL) and one phase encoding gradient (PE), and three imaging echoes E1, E2, E3 and one navigator echo Nr, Nc are acquired as shown at the dashed boxes in fig. 2. Among them, the three echoes E1, E2, E3 preceding the navigator echoes Nr, Nc are used for magnetic resonance imaging and are therefore referred to as imaging echoes. The navigator echoes Nr, Nc are used only for navigator monitoring and not for imaging use. As shown in fig. 2, in each repetition period, after the acquisition of the imaging echo is completed, a gradient field having the same magnitude and the opposite direction as the phase encoding gradient corresponding to the imaging echo is applied to completely invert the residual transverse magnetization component, so that the navigator echo Nr, Nc acquired after the inverse gradient field is an echo without the phase encoding gradient.
In this embodiment, in order to increase the acquisition speed, the navigator echoes Nr and Nc do not need to acquire a complete echo, and may be, for example, half-wave or other incomplete echoes. In addition, during the specific acquisition, an acquisition width wider than the acquisition bandwidths for acquiring the imaging echoes E1, E2 and E3 can be adopted to further accelerate the acquisition speed.
In this step, the reference navigation echo and the current navigation echo are constantly changed, that is, each navigation echo is the current navigation echo in the repetition period and is also the reference navigation echo of the next navigation echo.
Fig. 3A and 3B are schematic diagrams of a segmented linear phase correction model according to an embodiment of the invention. In fig. 3A, the abscissa is time t, the ordinate is phase change PV, the thin and tall rectangle is navigator echo Ne, and the short and thick rectangle is imaging echo E. It can be seen that the segmented linear phase correction model is established based on every two adjacent navigator echoes Ne in the embodiment of the present invention. In fig. 3B, the small square is the navigator echo Ne, and the thick and short rectangle is the imaging echo E. It can be seen that each linear phase correction model can obtain a triangular model as shown in fig. 3B based on the phase difference and the time difference between two adjacent navigator echoes Ne, the horizontal cathetus of the triangle corresponds to the time difference between the two adjacent navigator echoes Ne, i.e. the reference navigator echo and the current navigator echo, the vertical cathetus of the triangle corresponds to the phase difference between the two adjacent navigator echoes Ne, and the hypotenuse of the triangle is the linear phase difference.
And 103, aiming at each imaging echo in the current repetition period, obtaining a correction phase of the imaging echo by using a linear phase correction model corresponding to the current repetition period according to the time difference between the imaging echo and the reference navigation echo.
Based on the triangular model of fig. 3B, after determining the time difference between the imaging echo and the left reference navigator echo in the current repetition period, based on the proportional relationship between the time difference and the time difference between the two adjacent navigator echoes, the proportional relationship between the phase difference of the imaging echo relative to the left reference navigator echo and the phase difference between the two adjacent navigator echoes can be obtained, and based on the proportional relationship, the phase difference of the imaging echo relative to the left reference navigator echo can be obtained, such as E1PV, E2PV and E3PV shown in fig. 3B; and then according to the phase of the reference navigation echo on the left side, the corrected phase of the imaging echo can be obtained through addition.
The imaging echo phase correction method based on the multi-echo data combined imaging sequence in the embodiment of the present invention is described in detail above, and the imaging echo phase correction device based on the multi-echo data combined imaging sequence in the embodiment of the present invention is described below. The imaging echo phase correction device based on the multi-echo data combined imaging sequence in the embodiment of the present invention may be used to implement the imaging echo phase correction method based on the multi-echo data combined imaging sequence in the embodiment of the present invention, and for the content not disclosed in detail in the embodiment of the present invention, reference may be made to the corresponding description in the embodiment of the method of the present invention, which is not described herein again.
Fig. 4 is an exemplary block diagram of an imaging echo phase correction device based on a multi-echo data combination imaging sequence according to an embodiment of the present invention. As shown in fig. 4, the apparatus may include: an echo acquisition unit 401, a model building unit 402 and a phase determination unit 403.
The echo acquisition unit 401 is configured to acquire a navigation echo after an imaging echo in each repetition period when data acquisition is performed based on a multi-echo data combination imaging sequence, where the navigation echo is a phase-free encoding gradient echo. In this embodiment, in order to increase the acquisition speed, the echo acquisition unit 401 may acquire a navigation echo of a half-wave or other incomplete echo. In addition, during the specific acquisition, the echo acquisition unit 401 may also acquire the navigation echo with an acquisition width wider than an acquisition bandwidth for acquiring the imaging echo, so as to further increase the acquisition speed.
The model establishing unit 402 is configured to, for a current repetition period in each repetition period, use a navigation echo acquired in a previous repetition period adjacent to the current repetition period as a reference navigation echo, use the navigation echo acquired in the current repetition period as a current navigation echo, calculate a phase difference between the current navigation echo and the reference navigation echo, and establish a linear phase correction model corresponding to the current repetition period according to the phase difference, a time difference between the current navigation echo and the reference navigation echo, and a phase of the reference navigation echo.
The phase determining unit 403 is configured to, for each imaging echo in the current repetition period, obtain a corrected phase of the imaging echo according to a time difference between the imaging echo and the reference navigator echo by using a linear phase correction model corresponding to the current repetition period.
Fig. 5 is an exemplary structural diagram of another imaging echo phase correction device based on a multi-echo data combination imaging sequence in an embodiment of the present invention. As shown in fig. 5, may include: at least one memory 51 and at least one processor 52. In addition, some other components may be included, such as a communications port, etc. These components communicate over a bus.
Wherein the at least one memory 51 is adapted to store a computer program. In one embodiment, the computer program may be understood as the various modules of an imaging echo phase correction apparatus comprising the multi-echo data combining imaging sequence shown in fig. 4. Further, the at least one memory 51 may also store an operating system and the like. Operating systems include, but are not limited to: an Android operating system, a Symbian operating system, a Windows operating system, a Linux operating system, and the like.
The at least one processor 72 is configured to invoke the computer program stored in the at least one memory 51 to perform the method for imaging echo phase correction based on multi-echo data combined imaging sequence as described in the embodiments of the present invention. The processor 52 may be a CPU, processing unit/module, ASIC, logic module, or programmable gate array, etc. Which can receive and transmit data through the communication port.
The embodiment of the invention also provides a magnetic resonance imaging system, which can comprise the imaging echo phase correction device based on the multi-echo data combination imaging sequence in any one of the above embodiments.
It should be noted that not all steps and modules in the above flows and structures are necessary, and some steps or modules may be omitted according to actual needs. The execution order of the steps is not fixed and can be adjusted as required. The division of each module is only for convenience of describing adopted functional division, and in actual implementation, one module may be divided into multiple modules, and the functions of multiple modules may also be implemented by the same module, and these modules may be located in the same device or in different devices.
It is understood that the hardware modules in the above embodiments may be implemented mechanically or electronically. For example, a hardware module may include a specially designed permanent circuit or logic device (e.g., a special purpose processor such as an FPGA or ASIC) for performing specific operations. A hardware module may also include programmable logic devices or circuits (e.g., including a general-purpose processor or other programmable processor) that are temporarily configured by software to perform certain operations. The implementation of the hardware module in a mechanical manner, or in a dedicated permanent circuit, or in a temporarily configured circuit (e.g., configured by software), may be determined based on cost and time considerations.
In addition, a computer-readable storage medium is provided in an embodiment of the present invention, and has a computer program stored thereon, where the computer program is capable of being executed by a processor and implementing the method for imaging echo phase correction of a multi-echo data combining imaging sequence described in the embodiment of the present invention. Specifically, a system or an apparatus equipped with a storage medium on which a software program code that realizes the functions of any of the embodiments described above is stored may be provided, and a computer (or a CPU or MPU) of the system or the apparatus is caused to read out and execute the program code stored in the storage medium. Further, part or all of the actual operations may be performed by an operating system or the like operating on the computer by instructions based on the program code. The functions of any of the above-described embodiments may also be implemented by writing the program code read out from the storage medium to a memory provided in an expansion board inserted into the computer or to a memory provided in an expansion unit connected to the computer, and then causing a CPU or the like mounted on the expansion board or the expansion unit to perform part or all of the actual operations based on the instructions of the program code. Examples of the storage medium for supplying the program code include floppy disks, hard disks, magneto-optical disks, optical disks (e.g., CD-ROMs, CD-R, CD-RWs, DVD-ROMs, DVD-RAMs, DVD-RWs, DVD + RWs), magnetic tapes, nonvolatile memory cards, and ROMs. Alternatively, the program code may be downloaded from a server computer via a communications network.
Fig. 6 and 7 are schematic diagrams illustrating a comparison between a C-spine image (second row) obtained by a magnetic resonance imaging method using an imaging echo phase correction method of a multi-echo data combined imaging sequence according to an embodiment of the present invention and a C-spine image (first row) obtained by a conventional magnetic resonance imaging method (i.e., a method not using an embodiment of the present invention). The C-spine imaging in fig. 6 and 7 was performed on healthy volunteers on a 3T magnetic spectrum scanner with a 16 channel head and neck coil. The protocol parameters adopted when the method in the embodiment of the invention is adopted comprise: FOV (field of view window) 180 × 180mm2, flip angle 30 °; the number of slices is 30; distance factor is 10%; the slice thickness is 3 mm; TE/TR (echo time/repetition time) 15/545 ms; BW/pixel (sampling bandwidth/pixel) ═ 260 hz; the combined echo is 4; the scan time was 4:58 minutes. When the method in the embodiment of the invention is not adopted, similar protocol parameters are adopted, and the method specifically comprises the following steps: FOV (field of view window) 180 × 180mm2, flip angle 30 °; the number of slices is 30; distance factor is 10%; the slice thickness is 3 mm; TE/TR (echo time/repetition time) 15/550 ms; BW/pixel (sampling bandwidth/pixel) ═ 260 Hz; the combined echo is 4; the scan time was 4:38 minutes.
By comparing the first row image and the second row image in fig. 6, it can be seen that, compared with the conventional magnetic resonance imaging method, the magnetic resonance imaging method using the imaging echo phase correction method of the multi-echo data combination imaging sequence in the embodiment of the present invention obtains an image showing fewer artifacts and a clearer tissue interface. By comparing the first and second line images in fig. 7, it can be seen that the images obtained from the development sequence appear sharper.
It can be seen that respiratory motion during a magnetic resonance scan results in strong blurring and ghosting, and these negative effects may be caused not only by motion directly, but also by motion-induced magnetic field variations, the latter being particularly common at 3T or higher magnetic fields. The sectional linear phase correction model adopted in the embodiment of the invention can reduce the image blurring and ghosting phenomena caused by the negative effects by compensating the phase change of the imaging echo.
It can be seen from the above solution that in the embodiment of the present invention, a navigation echo is acquired after the imaging echo of each repetition period, and a piecewise linear phase correction model is established based on the phase difference and the time difference between adjacent navigation echoes, so that for each imaging echo in each repetition period, the corrected phase of the imaging echo is obtained by using the piecewise linear phase correction model according to the time difference between the imaging echo and the reference navigation echo. Thus, image artifacts caused by imaging echo phase errors caused directly or indirectly by respiratory motion can be eliminated.
In addition, the acquisition speed can be increased by acquiring the navigation echo of the incomplete wave such as the half wave or the like or acquiring the navigation echo by adopting a wider acquisition bandwidth.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (9)
1. An imaging echo phase correction method based on a multi-echo data combination imaging sequence is characterized by comprising the following steps:
acquiring a navigation echo after an imaging echo in each repetition period when data acquisition is performed based on a multi-echo data merging imaging sequence, wherein the navigation echo is a phase-free encoding gradient echo (101);
aiming at a current repetition period in each repetition period, taking a navigation echo acquired in a previous repetition period adjacent to the current repetition period as a reference navigation echo, taking the navigation echo acquired in the current repetition period as a current navigation echo, calculating a phase difference between the current navigation echo and the reference navigation echo, and establishing a linear phase correction model (102) corresponding to the current repetition period according to the phase difference, a time difference between the current navigation echo and the reference navigation echo and a phase of the reference navigation echo;
and aiming at each imaging echo in the current repetition period, obtaining a correction phase (103) of the imaging echo by utilizing the linear phase correction model according to the time difference between the imaging echo and the reference navigation echo.
2. The imaging echo phase correction method based on multi-echo data combined imaging sequence of claim 1,
the navigation echo is a half wave or other incomplete echo.
3. The imaging echo phase correction method based on multi-echo data combined imaging sequence of claim 1,
the navigation echo adopts an acquisition bandwidth with a first width, and the first width is larger than the acquisition bandwidth width for acquiring the imaging echo.
4. An imaging echo phase correction device based on a multi-echo data combination imaging sequence is characterized by comprising:
the echo acquisition unit (401) is used for acquiring a navigation echo after an imaging echo in each repetition period when data acquisition is carried out based on a multi-echo data merging imaging sequence, wherein the navigation echo is a phase-free encoding gradient echo;
a model establishing unit (402) for, for a current repetition period in each repetition period, taking a navigation echo acquired in a previous repetition period adjacent to the current repetition period as a reference navigation echo, taking the navigation echo acquired in the current repetition period as a current navigation echo, calculating a phase difference between the current navigation echo and the reference navigation echo, and establishing a linear phase correction model corresponding to the current repetition period according to the phase difference, a time difference between the current navigation echo and the reference navigation echo, and a phase of the reference navigation echo; and
a phase determining unit (403) configured to, for each imaging echo in the current repetition period, obtain a corrected phase of the imaging echo by using the linear phase correction model according to a time difference between the imaging echo and the reference navigator echo.
5. The imaging echo phase correction device based on multiple echo data combined imaging sequence according to claim 4, characterized in that the echo acquisition unit (401) acquires navigator echoes of half-waves or other incomplete echoes.
6. The imaging echo phase correction device based on multi-echo data combination imaging sequence of claim 4,
the echo acquisition unit (401) acquires the navigation echo by adopting an acquisition bandwidth with a first width, wherein the first width is larger than the acquisition bandwidth for acquiring the imaging echo.
7. An imaging echo phase correction device based on a multi-echo data combination imaging sequence is characterized by comprising: at least one memory (51) and at least one processor (52), wherein:
the at least one memory (51) is for storing a computer program;
the at least one processor (52) is configured to invoke a computer program stored in the at least one memory (51) to perform the method of imaging echo phase correction based on multi-echo data-merged imaging sequences according to any of claims 1 to 3.
8. A magnetic resonance imaging system comprising the multi-echo data combining imaging sequence-based imaging echo phase correction device of any one of claims 4 to 7.
9. A computer-readable storage medium having stored thereon a computer program; characterized in that the computer program is executable by a processor and implements the method for imaging echo phase correction based on multi-echo data combined imaging sequence according to any of claims 1 to 3.
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