Phase correction methods, apparatus, computer equipment and storage media

Abstract

This application relates to a phase correction method, apparatus, computer device, and storage medium. The method involves pre-scanning a target object with magnetic resonance imaging (MRI) to acquire multiple echo data. Based on these multiple echo data, reference echo data and echo data to be corrected are determined. Then, a correction phase difference is determined based on the reference and echo data to be corrected. This correction phase difference is then used to perform phase correction on the echo data to be corrected, resulting in corrected echo data corresponding to the original echo data. This method uses reference echo data for deviation correction, preserving phase information between different channels and the phase information between water and lipid components contained in the echo data. This provides reliable data for subsequent reconstruction of MRI images based on this important phase information.

Description

Technical Field

[0001] This application relates to the field of medical image processing technology, and in particular to a phase correction method, apparatus, computer device, and storage medium. Background Technology

[0002] In magnetic resonance multi-echo technology, echo phase correction is required to ensure data matching between multiple echoes.

[0003] Currently, there are many conventional echo phase correction methods. Among them, PROPELLER multi-echo phase correction is more commonly used. This method performs Fourier transform on the original data and triangular filtered data of each echo to obtain the original image and the filtered image. The amplitude of the original image is preserved, and the phase of the original image is subtracted from the phase of the filtered image to obtain new image data, which is the corrected image data for each echo. Then, the corrected image data is transformed into K-space for subsequent magnetic resonance image reconstruction.

[0004] However, the aforementioned phase correction method destroys the true phase of the original echo, which is not conducive to the effective application of image reconstruction methods based on phase information in the later stage. Summary of the Invention

[0005] Therefore, it is necessary to provide a phase correction method, apparatus, computer device, and storage medium for echoes to address the aforementioned technical problems. This method can retain important phase information while correcting the phase error of the echoes, so as to facilitate accurate and efficient image reconstruction based on the important phase information.

[0006] In a first aspect, a phase correction method, the method comprising:

[0007] Multiple echo data were obtained by pre-scanning the target object with magnetic resonance imaging;

[0008] Based on the multiple echo data, a reference echo data and an echo data to be corrected are determined;

[0009] The correction phase difference is determined based on the reference echo data and the echo data to be corrected;

[0010] The phase correction is used to perform phase correction on the echo data to be corrected, thereby obtaining corrected echo data corresponding to the echo data to be corrected; or the phase correction is used to perform phase correction on the reference echo data, thereby obtaining corrected echo data corresponding to the reference echo data.

[0011] In one embodiment, determining the reference echo data and the echo data to be corrected based on the plurality of echo data includes:

[0012] The reference echo data is determined based on multiple echo data sets;

[0013] From the plurality of echo data, an echo data that is different from the reference echo data is randomly selected and determined as the echo data to be corrected.

[0014] In one embodiment, determining the reference echo data and the echo data to be corrected based on the plurality of echo data includes:

[0015] The summation of the multiple echo data is used to determine the reference echo data;

[0016] Arbitrarily select one echo data from the multiple echo data to determine the echo data to be corrected.

[0017] In one embodiment, determining the correction phase difference based on the reference echo data and the echo data to be corrected includes:

[0018] Calculate the phase difference between the echo data to be corrected for each channel and the reference echo data for the corresponding channel;

[0019] The corrected phase difference is obtained based on the weighting factor of each channel and the phase difference of the corresponding channel.

[0020] In one embodiment, the weighting factor for each channel is determined as follows:

[0021] The weighting factor for each channel is determined based on the amplitude of the echo data to be corrected for each channel and the amplitude of the reference echo data for the corresponding channel.

[0022] In one embodiment, the step of using the corrected phase difference to perform phase correction on the echo data to be corrected, to obtain corrected echo data corresponding to the echo data to be corrected, includes:

[0023] The corrected phase difference is multiplied with the echo data to be corrected to obtain the corrected echo data corresponding to the echo data to be corrected.

[0024] The step of using the corrected phase difference to perform phase correction on the reference echo data to obtain corrected echo data corresponding to the reference echo data includes:

[0025] The corrected phase difference is multiplied by the reference echo data to obtain the corrected echo data corresponding to the reference echo data.

[0026] In one embodiment, after performing phase correction on the echo data to be corrected using the phase difference, the method further includes:

[0027] Determine whether each echo data in the plurality of echo data has been phase corrected;

[0028] If not, the echo data to be corrected is re-determined based on the multiple echo data, and the process returns to the step of determining the phase difference to be corrected based on the reference echo data and the echo data to be corrected, until the multiple echo data have all been phase corrected.

[0029] If so, the corrected echo data are superimposed to obtain the corrected target echo data.

[0030] Secondly, a phase correction device, the device comprising:

[0031] The acquisition module is used to acquire multiple echo data.

[0032] The first determining module is used to determine reference echo data and echo data to be corrected based on the multiple echo data.

[0033] The second determining module is used to determine the correction phase difference based on the reference echo data and the echo data to be corrected;

[0034] The correction module is used to perform phase correction on the echo data to be corrected using the correction phase difference to obtain corrected echo data corresponding to the echo data to be corrected, or to perform phase correction on the reference echo data using the correction phase difference to obtain corrected echo data corresponding to the reference echo data.

[0035] Thirdly, a computer device includes a memory and a processor, the memory storing a computer program, the processor executing the computer program to implement the method described in the first aspect.

[0036] Fourthly, a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the method described in the first aspect.

[0037] The aforementioned phase correction method, apparatus, computer equipment, and storage medium acquire multiple echo data by pre-scanning the target object with magnetic resonance imaging, determine reference echo data and echo data to be corrected based on the multiple echo data, determine the correction phase difference based on the reference echo data and echo data to be corrected, and then use the correction phase difference to perform phase correction on the echo data to be corrected to obtain the corrected echo data corresponding to the echo data to be corrected. The above method achieves phase correction of each echo data to be corrected by using the corrected phase difference, that is, it achieves deviation correction based on the reference echo data. In other words, it corrects the deviation information between each echo data. In practical applications, since the important phase information contained in each echo data in multiple scans, such as coil sensitivity phase information and water-fat phase information, remains basically unchanged, this part of the phase information is not considered deviation information. Deviation information often mainly comes from motion, system eddies, and other information that is not desired in the reconstructed image. Therefore, the above-mentioned important phase information will not be erased when correcting each echo data to be corrected in the later stage, but can be retained, thus providing a reliable data basis for the later reconstruction of magnetic resonance images based on this phase information. For example, iterative reconstruction or water-fat separation reconstruction can obtain better image effects and more information recovery. Attached Figure Description

[0038] Figure 1 This is an internal structural diagram of a computer device in one embodiment;

[0039] Figure 2 This is a flowchart illustrating a phase correction method in one embodiment;

[0040] Figure 3 for Figure 2 A flowchart illustrating one implementation of S102 in the embodiment;

[0041] Figure 4 for Figure 2 A flowchart illustrating another implementation of S102 in the embodiment;

[0042] Figure 5 for Figure 2 A flowchart illustrating one implementation of S103 in the embodiment;

[0043] Figure 6 for Figure 2 A flowchart illustrating another implementation of S103 in the embodiment;

[0044] Figure 7 This is a flowchart illustrating a phase correction method in one embodiment;

[0045] Figure 8 This is a flowchart illustrating a phase correction method in one embodiment;

[0046] Figure 9 This is a flowchart illustrating a phase correction method in one embodiment;

[0047] Figure 10 A schematic diagram of an image reconstructed from echo data;

[0048] Figure 11 A schematic diagram of an image reconstructed from echo data;

[0049] Figure 12 A schematic diagram of an image reconstructed from echo data;

[0050] Figure 13 This is a structural block diagram of the phase correction device in one embodiment;

[0051] Figure 14 This is a schematic diagram of multiple blades in the K space in one embodiment;

[0052] Figure 15 This is a schematic diagram of the phase correction process in one embodiment;

[0053] Figure 16 This is a structural block diagram of the phase correction device in one embodiment;

[0054] Figure 17 This is a structural block diagram of the phase correction device in one embodiment;

[0055] Figure 18 This is a structural block diagram of the phase correction device in one embodiment;

[0056] Figure 19 This is a structural block diagram of the phase correction device in one embodiment;

[0057] Figure 20 This is a structural block diagram of a phase correction device in one embodiment. Detailed Implementation

[0058] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0059] The phase correction method provided in this application can be applied to, for example... Figure 1 The computer device shown can be a server or a terminal, and its internal structure diagram can be as follows. Figure 1As shown, the computer device includes a processor, memory, network interface, display screen, and input devices connected via a system bus. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The network interface is used to communicate with external terminals via a network connection. When the computer program is executed by the processor, it implements a phase correction method. The display screen can be a liquid crystal display (LCD) or an e-ink display. The input devices can be a touch layer covering the display screen, buttons, a trackball, or a touchpad mounted on the computer device casing, or an external keyboard, touchpad, or mouse.

[0060] Those skilled in the art will understand that Figure 1 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0061] In one embodiment, such as Figure 2 As shown, a phase correction method is provided, which is applied to... Figure 1 Taking a computer device as an example, the explanation includes the following steps:

[0062] S101 acquires multiple echo data by pre-scanning the target object with magnetic resonance.

[0063] The target object can be any type of tissue, organ, morphological structure, bone, etc. Echo data refers to the scan data obtained when scanning the target object using an MRI scanner, i.e., the echo signal. Optionally, multiple echo data can be multiple gradient echoes acquired by switching the readout gradient field multiple times after a single radio frequency pulse excitation. Optionally, the echo data can correspond to different echo times, where each echo time represents the time interval from the midpoint of the pulse that generates the macroscopic transverse magnetization vector to the midpoint of the echo.

[0064] In practical applications, MRI equipment can be connected to computer equipment. The MRI equipment is used to scan the target object and obtain multiple echo data after scanning. The computer equipment reads multiple echo data from the MRI equipment, or the MRI equipment sends the multiple echo data obtained after scanning to the computer equipment so that the computer equipment can reconstruct the MRI image based on the multiple echo data.

[0065] S102, based on multiple echo data, determine the reference echo data and the echo data to be corrected.

[0066] Among them, the echo data to be corrected is the echo data whose phase error needs to be corrected, which is one of the multiple echo data acquired by the computer equipment; the reference echo data is the echo data used when correcting the echo data to be corrected, which can be one of the multiple echo data acquired by the computer equipment, or it can be the sum of multiple echo data.

[0067] Specifically, when a computer device acquires multiple echo data points, it can further filter out one echo data point as a reference echo data point. This filtering can be done randomly, by directly using the first echo data point as the reference echo data, or by using echo data points that meet preset conditions, such as echo data points with amplitudes greater than a preset amplitude threshold. After the computer device has selected the reference echo data point using the above method, the remaining echo data points can be used as echo data points to be corrected. Optionally, the computer device can also process the multiple echo data points first (e.g., perform a weighted summation operation) and use the processed echo data as the reference echo data point. In this case, the multiple echo data points initially acquired by the computer device are all echo data points to be corrected. The computer device can then use the reference echo data point to sequentially correct the phase error of the echo data points to be corrected.

[0068] S103, determine the correction phase difference based on the reference echo data and the echo data to be corrected.

[0069] The corrected phase difference can be the phase difference between the reference echo data and the echo data to be corrected, or optionally, the phase difference between a portion of the echo data in the reference echo data and a portion of the echo data to be corrected.

[0070] Specifically, once the computer equipment has determined the reference echo data and the echo data to be calibrated, it can use a corresponding phase difference calculation method to calculate the phase difference between the reference echo data and the echo data to be calibrated, thus obtaining the calibrated phase difference. Optionally, the computer equipment can also extract a portion of the echo data from the reference echo data and extract a portion of the echo data to be calibrated that is identical to the reference echo data, and then use a corresponding phase difference calculation method to calculate the phase difference between the portion of the echo data extracted from the reference echo data and the portion of the echo data extracted from the echo data to be calibrated, thus obtaining the calibrated phase difference.

[0071] S104, use the phase difference correction to perform phase correction on the echo data to be corrected, and obtain the corrected echo data corresponding to the echo data to be corrected.

[0072] Once the computer device obtains the corrected phase difference based on the above steps, it can use this corrected phase difference to perform phase correction on the echo data to be corrected, making the phase of the echo data to be corrected the same as the phase of the reference echo data. It should be noted that if the computer device uses any one of multiple echo data as the reference echo data, then the echo data to be corrected consists of all echo data except the reference echo data. Subsequently, the computer device needs to calculate the corrected phase difference between the reference echo data and each echo data to be corrected, and then use each corrected phase difference to correct each echo data to be corrected, making the phase of multiple echo data the same as the phase of the reference echo data, thereby completing the phase correction of multiple echo data for the same target object by the computer device. Optionally, if the computer device uses the sum of multiple echo data as the reference echo data when determining the reference echo data, then the echo data to be corrected is all the echo data contained in the multiple echo data. Later, the computer device also needs to calculate the correction phase difference between the reference echo data and each echo data to be corrected, and then use each correction phase difference to correct each echo data to be corrected, so that the phase of the multiple echo data is the same as the phase of the reference echo data, thereby completing the phase correction of multiple echo data of the same target object by the computer device.

[0073] In the above-disclosed embodiments, multiple echo data are acquired by pre-scanning the target object with magnetic resonance, and reference echo data and echo data to be corrected are determined based on the multiple echo data. Then, the correction phase difference is determined based on the reference echo data and echo data to be corrected, and the correction phase difference is used to perform phase correction on the echo data to be corrected to obtain the corrected echo data corresponding to the echo data to be corrected. The above method achieves phase correction of each echo data to be corrected by using the corrected phase difference, that is, it achieves deviation correction based on the reference echo data. In other words, it corrects the deviation information between each echo data. In practical applications, since the important phase information contained in each echo data in multiple scans, such as coil sensitivity phase information and water-fat phase information, remains basically unchanged, this part of the phase information is not considered deviation information. Deviation information often mainly comes from motion, system eddies, and other information that is not desired in the reconstructed image. Therefore, the above-mentioned important phase information will not be erased when correcting each echo data to be corrected in the later stage, but can be retained, thus providing a reliable data basis for the later reconstruction of magnetic resonance images based on this phase information. For example, iterative reconstruction or water-fat separation reconstruction can obtain better image effects and more information recovery.

[0074] In one embodiment, a specific implementation of the above S102 is provided, such as... Figure 3As shown, the above-mentioned S102 "determining reference echo data and echo data to be corrected based on multiple echo data" includes:

[0075] S201, determine reference echo data based on multiple echo data.

[0076] The reference echo data can be determined by arbitrarily selecting one echo from multiple echo data sets. Alternatively, after excitation with a small-angle radio frequency pulse, multiple gradient echoes can be acquired by switching the readout gradient field multiple times. These multiple gradient echoes are then encoded using the same phase, and merged and filled onto the same phase encoding line in K-space. The resulting data line is the reference echo data. In this embodiment, the reference echo data is formed by superimposing multiple echoes, improving the accuracy of the parameter data.

[0077] This embodiment relates to a method for a computer device to determine reference echo data. The method involves directly selecting an echo data point from multiple echo data points, either arbitrarily or randomly, as the reference echo data point. Alternatively, the computer device may first compare each echo data point in the multiple echo data points, and then select an echo data point from the multiple echo data points as the reference echo data point based on the comparison results. The specific comparison can be determined according to actual application requirements. For example, the amplitude of each echo data point can be compared.

[0078] S202, arbitrarily select an echo data that is different from the reference echo data from multiple echo data and determine it as the echo data to be corrected.

[0079] Once the computer device determines the reference echo data based on the aforementioned steps, it can arbitrarily select one of the remaining echo data from multiple echo data as the echo data to be calibrated, and wait for calibration. If the calibration is completed, it can then arbitrarily select another uncalibrated echo data from the remaining echo data as the echo data to be calibrated, until all echo data is calibrated.

[0080] In the above method, an echo data point is randomly selected from multiple echo data points as a reference echo data point, and then the echo data to be corrected is corrected using the reference echo data point. This method is simple and practical, and can directly use the original echo data without any processing of the echo data. To a certain extent, it can reduce the time for computer equipment to perform phase correction on the echo data, thereby improving the speed of phase correction.

[0081] In one embodiment, another specific implementation of S102 described above is provided, such as... Figure 4 As shown, the above-mentioned S102 "determining reference echo data and echo data to be corrected based on multiple echo data" includes:

[0082] S301, the echo data obtained by summing multiple echo data is determined as the reference echo data.

[0083] This embodiment relates to a method for a computer device to determine reference echo data. Specifically, when the computer device acquires multiple echo data points, it can perform a summation operation on these multiple echo data points to obtain a summed echo data point, which is then used as the reference echo data point. Specifically, during the summation operation, a direct summation operation can be performed; alternatively, a weighted summation operation can also be executed.

[0084] S302, arbitrarily select one echo data from multiple echo data to determine as the echo data to be corrected.

[0085] Once the computer device determines the reference echo data based on the aforementioned steps, it can arbitrarily select one echo data from multiple echo data as the echo data to be calibrated, and wait for calibration. After calibration is completed, it can then arbitrarily select another uncalibrated echo data from multiple echo data as the echo data to be calibrated, until all echo data are calibrated.

[0086] The above method uses the sum of multiple echo data as the reference echo data, which increases the amplitude of the reference echo data. This allows for subsequent correction of the echo data to be corrected based on the reference echo data, thereby improving the accuracy of the correction.

[0087] In one embodiment, a specific implementation of the above S103 is provided, such as... Figure 5 As shown, the above-mentioned S103 "determine the correction phase difference based on the reference echo data and the echo data to be corrected" includes:

[0088] S401, determine the weighting factor for each channel based on the amplitude of the echo data to be corrected for each channel and the amplitude of the reference echo data for the corresponding channel.

[0089] The echo data to be calibrated includes echo data from multiple channels, and the reference echo data includes reference echo data from multiple channels. The number of channels in the echo data to be calibrated is the same as the number of channels in the reference echo data, and there is a one-to-one correspondence between the echo data to be calibrated for each channel and the reference echo data for each channel.

[0090] Specifically, when the computer device acquires the echo data to be calibrated, it can further extract the amplitude of the echo data to be calibrated in each channel; correspondingly, when the computer device acquires the reference echo data, it can further extract the amplitude of the reference echo data in each channel. Then, the computer device can use a preset weighting factor calculation method to determine the weighting factor of each channel based on the amplitude of the echo data to be calibrated in each channel and the amplitude of the reference echo data in the corresponding channel. Optionally, the computer device can use the following relationships (1) and (2) to calculate the weighting factor of each channel:

[0091]

[0092] Sum=abs(∑T_i×conj(Adj_i)) (2);

[0093] In the above formula, T_abs_i represents the amplitude of the echo data to be corrected in the i-th channel; Adj_abs_i represents the amplitude of the reference echo data in the i-th channel, μ i The weight factor of the i-th channel is represented; T_i represents the echo data to be corrected in the i-th channel; Adj_i represents the reference echo data in the i-th channel; conj represents the conjugate operation; abs represents the absolute value operation; and Sum represents the summation operation.

[0094] S402, calculate the phase difference between the echo data to be corrected and the reference echo data of the corresponding channel for each channel.

[0095] Specifically, the echo data is obtained through multi-channel acquisition. When the computer device acquires the echo data to be calibrated and the reference echo data, it can directly use the phase difference calculation method to calculate the phase difference between the echo data to be calibrated in each channel and the reference echo data in the corresponding channel. Optionally, the computer device can use the following relationship (3) to calculate the phase difference between the echo data to be calibrated in each channel and the reference echo data in the corresponding channel:

[0096] delta_phase_i=T_phase_i×conj(Adj_phase_i) (3);

[0097] In the above formula, T_phase_i represents the phase of the echo data to be corrected in the i-th channel, where i is a positive integer; Adj_phase_i represents the phase of the reference echo data in the i-th channel; conj represents the conjugate operation; delta_phase_i represents the phase difference between the echo data to be corrected in the i-th channel and the reference echo data in the i-th channel.

[0098] S403, based on the weighting factor of each channel and the phase difference of the corresponding channel, obtains the corrected phase difference.

[0099] When the computer device obtains the weighting factor and phase difference of each channel of each echo data based on the aforementioned steps, it can further process and calculate the phase differences of all channels to obtain the corrected phase difference. Optionally, the computer device can calculate the corrected phase difference using the following formula (4):

[0100] delta_phase=∑μ i ×delta_phase_i (4);

[0101] In the above formula, delta_phase represents the corrected phase difference; μ i represents the weighting factor of the i-th channel; delta_phase_i represents the phase difference between the echo data to be corrected in the i-th channel and the reference echo data in the i-th channel.

[0102] This embodiment relates to a specific method for calculating the corrected phase difference. Since the signal-to-noise ratio of multiple channels of echo data differs at different image locations in practical applications, this embodiment needs to introduce a weighting factor for each channel in the process of determining the corrected phase difference. The larger the weighting factor, the larger the amplitude of the echo data of the corresponding channel, and the smaller the corresponding noise. Conversely, the smaller the weighting factor, the smaller the amplitude of the echo data of the corresponding channel, and the larger the corresponding noise. Therefore, adding a weighting factor to determine the corrected phase difference allows echo data with a larger weighting factor to contribute more information to the calculation of the corrected phase difference, thereby improving the accuracy of the calculated corrected phase difference.

[0103] In one embodiment, another specific implementation of S103 above is provided, such as... Figure 6 As shown, the above-mentioned S103 "determine the correction phase difference based on the reference echo data and the echo data to be corrected" includes:

[0104] S501, extract the reference echo data that overlaps with the echo data to be corrected from the reference echo data, and perform interpolation on the overlapping reference echo data to obtain candidate reference echo data.

[0105] Specifically, after the computer equipment acquires the reference echo data and the echo data to be corrected, it can extract the data overlapping with the echo data to be corrected from the reference echo data, using this as the reference echo data for the overlapping portion. Then, this reference echo data for the overlapping portion is interpolated to an image of the same size as the original reference echo data (K-space filling operation), or interpolated to an image of the same size as the target image, resulting in the interpolated image, i.e., the candidate reference echo data. The target image is the image formed after the final corrected echo data.

[0106] S502, extract the echo data to be corrected from the echo data to be corrected that overlaps with the reference echo data, and perform interpolation on the echo data to be corrected in the overlapping part to obtain candidate echo data to be corrected.

[0107] Specifically, after the computer device acquires the echo data to be calibrated and the reference echo data, it can extract the portion of the echo data to be calibrated that overlaps with the reference echo data. This overlapping portion of the echo data to be calibrated is then interpolated to an image of the same size as the image of the echo data to be calibrated, or to an image of the same size as the target image. The target image is the image formed after the echo data has been finally calibrated, and the resulting interpolated image is the candidate echo data to be calibrated. It should be noted that in this embodiment, the size of the image formed by the reference echo data is the same as the size of the image formed by the echo data to be calibrated.

[0108] S503, determine the candidate phase difference based on the candidate reference echo data and the candidate echo data to be corrected.

[0109] Once the computer equipment acquires the candidate reference echo data and the candidate echo data to be corrected, it can then base its data on... Figure 5 The calculation method described in the embodiment obtains the corrected phase difference between the candidate reference echo data and the candidate echo data to be corrected, which is the candidate phase difference in this embodiment.

[0110] The above embodiments involve phase correction of the overlapping portion of reference echo data and echo data to be corrected. This is mainly for application scenarios where the reference echo data and echo data to be corrected may include different echo data. Therefore, in this case, this embodiment provides the above method to correct the phase deviation between the reference echo data and the echo data to be corrected.

[0111] Correspondingly, S104 above, "using the correction phase difference to perform phase correction on the echo data to be corrected, to obtain the corrected echo data corresponding to the echo data to be corrected," specifically includes:

[0112] The candidate phase difference is used to perform phase correction on the candidate echo data to be corrected, so as to obtain the corrected echo data corresponding to the candidate echo data to be corrected.

[0113] When the computer device obtains the candidate phase difference based on step S503 above, it can use the candidate phase difference to perform phase correction on the candidate echo data to be corrected, so that the phase of the candidate echo data to be corrected is the same as the phase of the candidate reference echo data. The specific phase correction method involved in this embodiment is basically the same as the method described in S104 above. Please refer to the foregoing description for details, which will not be repeated here.

[0114] The following example illustrates Figure 6 The method for determining the corrected phase difference described in the embodiment is illustrated by using multiple echo data acquired through PROPELLER (Periodically Rotated Overlapping Parallel Lines with Enhanced Reconstruction) imaging technology.

[0115] For example, suppose multiple echo data include a first set of echo data, a second set of echo data, and a third set of echo data, and these multiple echo data fill multiple blades in the K-space of a magnetic resonance imaging (MRI) system. Specifically, such as... Figure 13 The diagram shows multiple blades in the K-space, including a first blade K1, a second blade K2, and a third blade K3. The first set of echo data is filled into the first blade K1; the second set of echo data is filled into the second blade K2; and the third set of echo data is filled into the third blade K3. The specific phase correction process based on K1, K2, and K3 is as follows: Figure 14 As shown, the process includes: first, extracting the data from the overlapping area (black area in the figure) of the three blades and transforming it to the image domain for comparison, obtaining the phases Is1, Is2, and Is3 of the echo data to be corrected. Taking Is1 and Is2 as an example, after comparing Is1 and Is2, the phase difference delta12 between Is1 and Is2 is obtained. Then, delta12 is transformed to K-space to obtain the spatially transformed phase difference Kd12. To ensure the consistency of K-space data, Kd12 is directly placed in a K-space of the same size as K2, and the rest is filled with 0 (a low-pass filter can be added). Then, it is transformed to the image domain to obtain Id12. K2 is transformed to the image domain to obtain image I2. The phase of Id12 is subtracted from I2 to obtain I2_cor. Then, it is transformed back to K-space to obtain K2_corr. K2_corr is the K-space after phase correction. Similarly, Is2 and Is3 can be operated on in the same way to obtain K3_corr, and then the phase-corrected K space can be obtained.

[0116] In one embodiment, a specific implementation of S104 is provided. Specifically, S104, "using the phase difference correction to perform phase correction on the echo data to be corrected, to obtain the corrected echo data corresponding to the echo data to be corrected," includes:

[0117] The corrected phase difference is multiplied with the echo data to be corrected to obtain the corrected echo data corresponding to the echo data to be corrected.

[0118] Specifically, when the computer device obtains the corrected phase difference, it can use a corresponding phase correction method to perform phase correction on the echo data to be corrected based on the corrected phase difference, thereby obtaining the corrected echo data corresponding to the echo data to be corrected. Optionally, the computer device can use the following relationships (5) and (6) to calculate the corrected echo data based on the corrected phase difference:

[0119] Adj_renew=Adj×delta_phase (5);

[0120] Adj=Adj_abs_i×Adj_phase_i (6);

[0121] In the above formula, Adj represents the echo data to be calibrated; Adj_abs_i represents the amplitude of the echo data to be calibrated; Adj_phase_i represents the phase of the echo data to be calibrated; delta_phase represents the corrected phase difference; and Adj_renew represents the calibrated echo data corresponding to the echo data to be calibrated. It should be noted that Adj can be the echo data to be calibrated from any channel, or it can be the echo data to be calibrated from all channels.

[0122] In one embodiment, a phase correction method is also provided, such as Figure 7 As shown, in Figure 2 In addition to the method described in the embodiments, the method further includes the following steps:

[0123] S601, determine whether each echo data in the multiple echo data has completed phase correction; if not, proceed to step S602; if yes, proceed to step S603.

[0124] After the computer device corrects one of the echo data to be corrected from multiple echo data based on the methods described in all the foregoing embodiments, it needs to continue correcting the remaining echo data from the multiple echo data until all echo data have been corrected. Therefore, after the computer device corrects one echo data, it also needs to determine whether all echo data from the multiple echo data have completed phase correction. If so, the correction stops; if not, the correction continues.

[0125] S602, redetermine the echo data to be corrected based on multiple echo data, and return to execute the step of determining the corrected phase difference based on the reference echo data and the echo data to be corrected, until the phase correction of multiple echo data has been completed.

[0126] This embodiment involves a computer device determining that uncorrected echo data still exists among multiple echo data sets. In this scenario, the computer device reselects an uncorrected echo data set from the multiple echo data sets and identifies it as the echo data to be corrected, then returns to the previous execution. Figure 2In the embodiment, steps S103 and thereafter perform phase correction on the redefined echo data to be corrected, and so on, until all echo data that needs to be corrected is corrected.

[0127] S603 performs superposition calculations on the corrected multiple echo data to obtain the corrected target echo data.

[0128] In practical applications, since multiple echo data are obtained from the same target object during scanning, after the computer device obtains the corrected multiple echo data, it can perform superposition operation (i.e., cumulative sum operation or weighted cumulative sum operation) on the corrected multiple echo data to obtain the superimposed echo data, which is the corrected target echo data.

[0129] In summary, based on all the above embodiments, this application also provides a phase correction method, such as... Figure 8 As shown, the method includes:

[0130] The S701 acquires multiple echo data by pre-scanning the target object using a magnetic resonance imaging (MRI) device.

[0131] S702 allows you to arbitrarily select one echo data from multiple echo data sets as the reference echo data.

[0132] S703: Randomly select an echo data that is different from the reference echo data from multiple echo data and determine it as the echo data to be corrected.

[0133] S704 determines the weighting factor for each channel based on the amplitude of the echo data to be corrected for each channel and the amplitude of the reference echo data for the corresponding channel.

[0134] S705 calculates the phase difference between the echo data to be corrected and the reference echo data of the corresponding channel for each channel.

[0135] S706, based on the weighting factor of each channel and the phase difference of the corresponding channel, obtains the corrected phase difference.

[0136] S707 performs a multiplication operation between the corrected phase difference and the echo data to be corrected to obtain the corrected echo data corresponding to the echo data to be corrected.

[0137] S708, determine whether each echo data in the multiple echo data has completed phase correction; if not, proceed to step S709; if yes, proceed to step S710.

[0138] S709: Based on multiple echo data, re-determine the echo data to be corrected, and return to execute step S704 until all multiple echo data have been phase corrected.

[0139] S710 performs superposition calculations on multiple corrected echo data to obtain the corrected target echo data.

[0140] For a description of each step in the above embodiments, please refer to the foregoing description, which will not be repeated here.

[0141] In summary, based on all the above embodiments, this application also provides another phase correction method, such as... Figure 9 As shown, the method includes:

[0142] The S801 acquires multiple echo data by pre-scanning the target object using a magnetic resonance imaging (MRI) device.

[0143] S802, the echo data obtained by summing multiple echo data is determined as the reference echo data.

[0144] S803 allows you to arbitrarily select one echo data from multiple echo data sets as the echo data to be corrected.

[0145] S804: Extract the reference echo data that overlaps with the echo data to be corrected from the reference echo data to obtain candidate reference echo data.

[0146] S805: Extract the echo data to be corrected from the echo data to be corrected that overlaps with the reference echo data to obtain candidate echo data to be corrected.

[0147] S806, determine the weighting factor for each channel based on the amplitude of the candidate echo data to be corrected for each channel and the amplitude of the candidate reference echo data for the corresponding channel.

[0148] S807, calculate the phase difference between the candidate echo data to be corrected and the candidate reference echo data of the corresponding channel for each channel.

[0149] S808 obtains the corrected phase difference based on the weighting factor of each channel and the phase difference of the corresponding channel.

[0150] S809, multiply the corrected phase difference with the candidate echo data to be corrected to obtain the corrected echo data corresponding to the candidate echo data.

[0151] S810, determine whether each echo data in the multiple echo data has completed phase correction; if not, proceed to step S811; if yes, proceed to step S812.

[0152] S811, based on multiple echo data, redetermine the echo data to be corrected, and return to the execution of step S804 until all multiple echo data have been phase corrected.

[0153] S812 performs superposition calculations on multiple corrected echo data to obtain the corrected target echo data.

[0154] For a description of each step in the above embodiments, please refer to the foregoing description, which will not be repeated here.

[0155] In summary, this application also provides a magnetic resonance imaging method capable of achieving PROPELLER imaging with Dixon water-lipid separation, comprising:

[0156] First, N k-space PROPELLER blades are collected, where N is an integer greater than 1. In this embodiment, each PROPELLER blade is as follows: Figure 13 The first blade K1, the second blade K2, and the third blade K3 are shown.

[0157] Next, phase correction is performed on the N k-space PROPELLER blades to obtain multiple corrected PROPELLER blades. In this embodiment, the phase correction process for each k-space PROPELLER blade is as follows: Figures 2 to 6 The steps are shown.

[0158] Furthermore, the Dixon technique is used to reconstruct two or more leaf image data from multiple corrected PROPELLER leaves; and the two or more leaf image data are combined to generate water and fat leaf image data.

[0159] Finally, the water leaf image data and fat leaf image data are transformed into water k-space leaf data and fat k-space leaf data, respectively, and PROPELLER reconstruction of the water k-space leaf data and fat k-space leaf data is performed. In this embodiment, the phase correction of the k-space PROPELLER leaf can remove the phase difference between multiple echoes, while retaining phase information other than the phase difference, such as the phase information between channels and the phase information between water and fat, thereby enabling Dixon water-fat separation PROPELLER imaging and obtaining better image results.

[0160] Phase correction of echo data can be achieved based on any of the above embodiments, resulting in the following: Figures 11-12 The resulting image is shown. Figure 10 To reconstruct the image from the echo data after phase correction using the existing PROPELLER phase correction algorithm, it is obvious... Figure 10 There is no phase information in the image, meaning that the phase information was erased when correcting the phase error of each echo data. Therefore, the image reconstructed from the phase-corrected echo data does not contain any phase information. Figure 11 To reconstruct an image based on the phase correction data of a certain channel after phase correction of the echo data using the phase correction method proposed in this application, it is obvious that... Figure 11 It contains very obvious phase information. Figure 12 This is a reconstructed image formed by superimposing the phase-corrected echo data from multiple echo data points. Figure 12 The phase information is displayed more clearly.

[0161] It should be understood that, although Figure 2-9 The steps in the flowchart are shown in sequence as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders. In addition, Figure 2-9 At least some of the steps in the process may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but may be executed at different times. The execution order of these steps or stages is not necessarily sequential, but may be executed in turn or alternately with other steps or at least some of the steps or stages in other steps.

[0162] In one embodiment, such as Figure 15 As shown, a phase correction device is provided, comprising: an acquisition module 11, a first determination module 12, a second determination module 13, and a correction module 14, wherein:

[0163] Acquisition module 11 is used to acquire multiple echo data;

[0164] The first determining module 12 is used to determine reference echo data and echo data to be corrected based on the plurality of echo data.

[0165] The second determining module 13 is used to determine the correction phase difference based on the reference echo data and the echo data to be corrected;

[0166] The correction module 14 is used to perform phase correction on the echo data to be corrected using the correction phase difference, so as to obtain the corrected echo data corresponding to the echo data to be corrected.

[0167] In one embodiment, such as Figure 16 As shown, the first determining module 12 includes:

[0168] The first determining unit 121 is configured to determine the reference echo data based on the plurality of echo data;

[0169] The second determining unit 122 is used to arbitrarily select an echo data that is different from the reference echo data from the plurality of echo data and determine it as the echo data to be corrected.

[0170] In one embodiment, such as Figure 17As shown, the first determining module 12 includes:

[0171] The third determining unit 123 is used to determine the echo data after summing the multiple echo data as the reference echo data;

[0172] The fourth determining unit 124 is used to arbitrarily select one echo data from the plurality of echo data and determine it as the echo data to be corrected.

[0173] In one embodiment, such as Figure 18 As shown, the second determining module 13 mentioned above includes:

[0174] The fifth determining unit 131 is used to determine the weighting factor of each channel based on the amplitude of the echo data to be corrected in each channel and the amplitude of the reference echo data in the corresponding channel.

[0175] The calculation unit 132 is used to calculate the phase difference between the echo data to be corrected in each channel and the reference echo data in the corresponding channel;

[0176] The sixth determining unit 133 is used to obtain the corrected phase difference based on the weighting factor of each channel and the phase difference of the corresponding channel.

[0177] In one embodiment, such as Figure 19 As shown, the second determining module 13 mentioned above includes:

[0178] The first extraction unit 134 is used to extract the reference echo data that overlaps with the echo data to be corrected from the reference echo data, and to perform interpolation on the reference echo data of the overlapping part to obtain candidate reference echo data.

[0179] The second extraction unit 135 is used to extract the echo data to be corrected that overlaps with the reference echo data from the echo data to be corrected, and to perform interpolation on the echo data to be corrected in the overlapping part to obtain candidate echo data to be corrected.

[0180] The seventh determining unit 136 is used to determine the candidate phase difference based on the candidate reference echo data and the candidate echo data to be corrected.

[0181] Correspondingly, the aforementioned correction module 14 is specifically used to perform phase correction on the candidate echo data to be corrected using the candidate phase difference, so as to obtain the corrected echo data corresponding to the candidate echo data to be corrected.

[0182] In one embodiment, the correction module 14 is further configured to perform a multiplication operation between the correction phase difference and the echo data to be corrected, so as to obtain the corrected echo data corresponding to the echo data to be corrected.

[0183] In one embodiment, the aforementioned phase correction device, such as Figure 20 As shown, it also includes:

[0184] The judgment module 15 is used to determine whether each echo data in the plurality of echo data has completed phase correction; if not, the echo data to be corrected is re-determined based on the plurality of echo data, and the step of determining the corrected phase difference based on the reference echo data and the echo data to be corrected is returned to be executed until the plurality of echo data have all completed phase correction; if yes, the corrected plurality of echo data are superimposed to obtain the corrected target echo data.

[0185] Specific limitations regarding the phase correction device can be found in the limitations of the phase correction method above, and will not be repeated here. Each module in the aforementioned phase correction device can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in hardware or independently of the processor in the computer device, or stored in software in the memory of the computer device, so that the processor can call and execute the operations corresponding to each module.

[0186] In one embodiment, a computer device is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to perform the following steps:

[0187] Multiple echo data were obtained by pre-scanning the target object with magnetic resonance imaging;

[0188] Based on the multiple echo data, a reference echo data and an echo data to be corrected are determined;

[0189] The correction phase difference is determined based on the reference echo data and the echo data to be corrected;

[0190] The phase correction is used to perform phase correction on the echo data to be corrected, so as to obtain the corrected echo data corresponding to the echo data to be corrected.

[0191] The computer device provided in the above embodiments has a similar implementation principle and technical effect to the above method embodiments, and will not be described again here.

[0192] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon, the computer program performing the following steps when executed by a processor:

[0193] Multiple echo data were obtained by pre-scanning the target object with magnetic resonance imaging;

[0194] Based on the multiple echo data, a reference echo data and an echo data to be corrected are determined;

[0195] The correction phase difference is determined based on the reference echo data and the echo data to be corrected;

[0196] The phase correction is used to perform phase correction on the echo data to be corrected, so as to obtain the corrected echo data corresponding to the echo data to be corrected.

[0197] The computer-readable storage medium provided in the above embodiments has a similar implementation principle and technical effect to the above method embodiments, and will not be described again here.

[0198] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the methods described above. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, or optical storage, etc. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0199] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0200] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A phase correction method, characterized in that, The method includes: Multiple echo data were obtained by pre-scanning the target object with magnetic resonance imaging; Based on the multiple echo data, a reference echo data and an echo data to be corrected are determined; Calculate the phase difference between the echo data to be corrected for each channel and the reference echo data for the corresponding channel; The weighting factor for each channel is determined based on the amplitude of the echo data to be corrected for each channel and the amplitude of the reference echo data for the corresponding channel. The corrected phase difference is obtained based on the weighting factor of each channel and the phase difference of the corresponding channel; The phase correction is used to perform phase correction on the echo data to be corrected, so as to obtain the corrected echo data corresponding to the echo data to be corrected.

2. The method according to claim 1, characterized in that, The step of determining the reference echo data and the echo data to be corrected based on the multiple echo data includes: The reference echo data is determined based on multiple echo data sets; From the plurality of echo data, an echo data that is different from the reference echo data is randomly selected and determined as the echo data to be corrected.

3. The method according to claim 1, characterized in that, The step of determining the reference echo data and the echo data to be corrected based on the multiple echo data includes: The summation of the multiple echo data is used to determine the reference echo data; Arbitrarily select one echo data from the multiple echo data to determine the echo data to be corrected.

4. The method according to claim 1, characterized in that, The step of using the corrected phase difference to perform phase correction on the echo data to be corrected, to obtain corrected echo data corresponding to the echo data to be corrected, includes: The corrected phase difference is multiplied by the echo data to be corrected to obtain the corrected echo data corresponding to the echo data to be corrected.

5. The method according to claim 1, characterized in that, After performing phase correction on the echo data to be corrected using the phase difference, the method further includes: Determine whether each echo data in the plurality of echo data has been phase corrected; If not, the echo data to be corrected is re-determined based on the multiple echo data, and the process returns to the step of determining the phase difference to be corrected based on the reference echo data and the echo data to be corrected, until the multiple echo data have all been phase corrected. If so, the corrected echo data are superimposed to obtain the corrected target echo data.

6. A phase correction device, characterized in that, The device includes: The acquisition module is used to acquire multiple echo data by pre-scanning the target object with magnetic resonance. The first determining module is used to determine reference echo data and echo data to be corrected based on the multiple echo data. The second determining module is used to calculate the phase difference between the echo data to be corrected in each channel and the reference echo data in the corresponding channel; determine the weighting factor of each channel based on the amplitude of the echo data to be corrected in each channel and the amplitude of the reference echo data in the corresponding channel; and obtain the corrected phase difference based on the weighting factor of each channel and the phase difference of the corresponding channel. The correction module is used to perform phase correction on the echo data to be corrected using the correction phase difference, so as to obtain the corrected echo data corresponding to the echo data to be corrected.

7. The apparatus according to claim 6, characterized in that, The first determining module includes: The first determining unit is specifically used to determine the reference echo data based on the plurality of echo data; The second determining unit is specifically used to arbitrarily select an echo data that is different from the reference echo data from the plurality of echo data and determine it as the echo data to be corrected.

8. The apparatus according to claim 6, characterized in that, The first determining module includes: The third determining unit is specifically used to determine the reference echo data by summing up the multiple echo data; The fourth determining unit is specifically used to arbitrarily select one echo data from the plurality of echo data to determine as the echo data to be corrected.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 5.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 5.

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