Method, system, device and medium for generating magnetic resonance images

Abstract

The application discloses a kind of generation methods, systems, equipment and medium of magnetic resonance image, method includes: obtaining multiple target personnel multiple first magnetic resonance image, and based on multiple first magnetic resonance image obtains the position information of target site in each first magnetic resonance image;According to multiple position information, respectively to multiple target sites are radio frequency transmitting field local shimming to respectively obtain the amplitude and phase of local shimming after transmitting channel, to obtain multiple radio frequency transmitting field local shimming after transmitting channel amplitude and phase;Based on multiple radio frequency transmitting field local shimming after transmitting channel amplitude and phase, obtain a group of transmitting channel target amplitude and target phase;With a group of transmitting channel target amplitude and target phase as the initial amplitude and initial phase of transmitting channel when next time scanning, scanning target personnel to generate target magnetic resonance image, so that the local spatial distribution of radio frequency transmitting field is uniform in magnetic resonance image generation process.

Description

Technical Field

[0001] This invention relates to the field of magnetic resonance imaging technology, and in particular to a method, system, device and medium for generating magnetic resonance images. Background Technology

[0002] MRI (Magnetic Resonance Imaging) is a medical imaging technique used for medical diagnosis. MRI scanners use strong magnetic fields, magnetic field gradients, and radio waves to generate images of the object being scanned (e.g., tissues or organs in the human body). Cardiac MRI images are commonly used to assess cardiac function parameters and diagnose cardiovascular diseases, and are considered the gold standard for quantitative cardiac analysis. Compared to low-field MRI, ultra-high-field MRI has a higher signal-to-noise ratio and tissue contrast, making it more suitable for observing the fine structure and metabolic physiological changes of cardiac tissue. However, increased field strength shortens the radiofrequency wavelength, making it easier to form standing waves in the imaging field of the human heart, causing B1. + Uneven local spatial distribution of the (radio frequency emission field) can cause "black holes" in the image, affecting image quality and clinical diagnosis.

[0003] Currently, B1 is used for ultra-high field magnetic resonance imaging. + Spatial inhomogeneity often necessitates global B1 calibration before clinical scanning. + Homogenization has a long calibration time, and global homogenization is difficult to guarantee the B1 value of the scanned area. + Uniformity. Besides global shimming, local shimming is also a commonly used method, which shims a specific ROI (Region of Interest) to improve the B1 resolution of that ROI. + Non-uniformity. Both global and local shimming require a calibration process. This process is affected by factors such as the patient's breathing, heartbeat, and ECG status, resulting in insufficient stability. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the defect of uneven local spatial distribution of radio frequency emission field in the process of magnetic resonance image generation in the prior art, and to provide a method, system, device and medium for generating magnetic resonance images.

[0005] The present invention solves the above-mentioned technical problems through the following technical solution:

[0006] This invention provides a method for generating magnetic resonance images, the method comprising:

[0007] Acquire multiple sets of first magnetic resonance images of multiple target individuals, and obtain the location information of the target part in each set of first magnetic resonance images based on the multiple sets of first magnetic resonance images;

[0008] According to the plurality of position information, a radio frequency transmit field local shimming is performed on each of the plurality of target parts to obtain the amplitude and phase of the transmit channel after local shimming, thereby obtaining a plurality of sets of the amplitude and phase of the transmit channel after local shimming of the radio frequency transmit field;

[0009] Based on the plurality of sets of the amplitude and phase of the transmit channel after local shimming of the radio frequency transmit field, a target amplitude and a target phase of a set of transmit channels are obtained;

[0010] The target amplitude and the target phase of the set of transmit channels are used as the initial amplitude and the initial phase of the transmit channel for the next scan, and the target person is scanned to generate a target magnetic resonance image.

[0011] Preferably, the step of obtaining the position information of the target part in each of the plurality of first magnetic resonance images based on the plurality of first magnetic resonance images comprises:

[0012] Based on the plurality of first magnetic resonance images, an image recognition model is used to obtain the position information of the target part in each of the plurality of first magnetic resonance images.

[0013] Preferably, the step of performing radio frequency transmit field local shimming on each of the plurality of target parts to obtain the amplitude and phase of the transmit channel after local shimming comprises:

[0014] A plurality of sets of second magnetic resonance images of a plurality of target persons are obtained;

[0015] Based on the plurality of sets of second magnetic resonance images, the transmit sensitivity of a plurality of sets of transmit channels is obtained;

[0016] A penalty function is used to calculate the target weight corresponding to the transmit sensitivity of the plurality of sets of transmit channels;

[0017] Based on the target weight, the amplitude and phase of the transmit channel after local shimming of the radio frequency transmit field are obtained.

[0018] Preferably, before the step of calculating the target weight of the plurality of sets of transmit channels using the penalty function, the step of performing radio frequency transmit field local shimming on each of the plurality of target parts to obtain the amplitude and phase of the transmit channel after local shimming of the radio frequency transmit field further comprises:

[0019] A mask is applied to the area outside the target part to obtain the amplitude and phase of the transmit channel after local shimming of the radio frequency transmit field.

[0020] Preferably, the step of obtaining the target amplitude and the target phase of a set of transmit channels based on the plurality of sets of the amplitude and phase of the transmit channel after local shimming of the radio frequency transmit field comprises:

[0021] Multiple sets of third magnetic resonance images are generated by scanning multiple target personnel using the amplitude and phase of the transmission channels after local shimming of multiple radio frequency transmission fields;

[0022] Determine whether each group of the third magnetic resonance images meets the requirements. If so, use the amplitude and phase of the transmission channel corresponding to the third magnetic resonance image as the candidate amplitude and candidate phase of the transmission channel, respectively.

[0023] The average value of the candidate amplitude and the average value of the candidate phase corresponding to the candidate amplitude and the candidate phase are obtained respectively, and the average value of the candidate amplitude and the average value of the candidate phase are respectively used as the target amplitude and target phase of a set of transmission channels.

[0024] Preferably, the step of determining whether each group of the third magnetic resonance images meets the requirements includes:

[0025] Obtain the coefficient of variation of the target region in the third magnetic resonance image generated by the amplitude and phase scan of the transmission channel after local shimming of the radio frequency transmission field for each group;

[0026] Determine whether the coefficient of variation is less than a preset threshold. If so, the third magnetic resonance image meets the requirements.

[0027] Preferably, the step of obtaining the average value of the candidate amplitude and the average value of the candidate phase corresponding to the candidate amplitude and candidate phase respectively includes:

[0028] Select the third magnetic resonance image whose coefficient of variation is less than a preset threshold;

[0029] Histograms are constructed based on the amplitude and phase corresponding to the third magnetic resonance image, respectively.

[0030] Based on the histogram, the average value of the candidate amplitude and the average value of the candidate phase corresponding to the candidate amplitude and candidate phase are obtained.

[0031] The present invention also provides a system for generating magnetic resonance images, the system comprising:

[0032] The first acquisition module is used to acquire multiple sets of first magnetic resonance images of multiple target persons, and to acquire the location information of the target part in each set of first magnetic resonance images based on the multiple sets of first magnetic resonance images;

[0033] The second acquisition module is used to perform local shimming of the radio frequency transmission field on the multiple target locations according to the multiple location information to obtain the amplitude and phase of the transmission channel after local shimming of the radio frequency transmission field, and to obtain multiple sets of amplitude and phase of the transmission channel after local shimming of the radio frequency transmission field.

[0034] The third acquisition module is configured to acquire target amplitude and target phase of a group of transmission channels based on the amplitudes and phases of the transmission channels after the local shimming of the multiple groups of radio frequency transmission fields.

[0035] The scanning module is configured to use the target amplitude and target phase of the group of transmission channels as initial amplitude and initial phase of the transmission channels in the next scan to scan the target person to generate a target magnetic resonance image.

[0036] The present application also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the method for generating a magnetic resonance image as described above when executing the computer program.

[0037] The present application also provides a computer readable storage medium, which stores a computer program, wherein the computer program is executable on a processor to implement the method for generating a magnetic resonance image as described above.

[0038] On the basis of common knowledge in the art, the above-mentioned preferred conditions can be combined in any manner to obtain preferred examples of the present application.

[0039] The positive progress effect of the present application is that:

[0040] The present application acquires multiple groups of first magnetic resonance images of multiple target persons, acquires position information of a target part in each group of first magnetic resonance images based on the multiple groups of first magnetic resonance images, performs local shimming of a radio frequency transmission field on the multiple target parts to obtain amplitudes and phases of transmission channels after the local shimming of the multiple groups of radio frequency transmission fields, acquires target amplitude and target phase of a group of transmission channels based on the amplitudes and phases of the transmission channels after the local shimming of the multiple groups of radio frequency transmission fields, and uses the target amplitude and target phase of the group of transmission channels as initial amplitude and initial phase of the transmission channels in the next scan to scan the target person to generate a target magnetic resonance image. The present application can obtain the optimal amplitudes and phases of a group of transmission channels from the amplitudes and phases of the transmission channels after the local shimming of the multiple groups of radio frequency transmission fields, so as to use the optimal amplitudes and phases as the initial amplitude and initial phase of the transmission channels in the next scan, and further make the local spatial distribution of the radio frequency transmission field uniform in the magnetic resonance image generation process, thereby improving the quality of the scanned image and the accuracy of clinical diagnosis. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 The flowchart of the method for generating a magnetic resonance image of the present application embodiment 1.

[0042] Figure 2 The flowchart of step 102 in the present application embodiment 1.

[0043] Figure 3This is a flowchart of step 103 in Embodiment 1 of the present invention.

[0044] Figure 4 This is a schematic diagram of a histogram in Embodiment 1 of the present invention.

[0045] Figure 5 This is a schematic diagram of the modules of the magnetic resonance image generation system of Embodiment 2 of the present invention.

[0046] Figure 6 This is a schematic diagram of the second acquisition module in Embodiment 2 of the present invention.

[0047] Figure 7 This is a schematic diagram of the third acquisition module in Embodiment 2 of the present invention.

[0048] Figure 8 This is a schematic diagram of the electronic device according to Embodiment 3 of the present invention. Detailed Implementation

[0049] The present invention will be further illustrated by way of embodiments below, but the present invention is not limited to the scope of the embodiments described herein.

[0050] Example 1

[0051] like Figure 1 As shown, this embodiment discloses a method for generating magnetic resonance images, the method comprising:

[0052] Step S101: Obtain multiple sets of first magnetic resonance images of multiple target persons, and obtain the location information of the target part in each set of first magnetic resonance images based on the multiple sets of first magnetic resonance images;

[0053] Specifically, multiple sets of first magnetic resonance images can be generated by scanning multiple target individuals of different genders and body types, such as volunteers. A set of first magnetic resonance images is generated when scanning each target individual, and the target body part corresponding to each target individual is determined from the set of magnetic resonance images. Each set of first magnetic resonance images may contain one or more first magnetic resonance images. These first magnetic resonance images are used to identify the target body part and can be GRE (Gradient Echo Series) images or FSE (Fast Spin Echo Series) images. The first magnetic resonance images include the anatomy information of the target individual and at least include the target body part.

[0054] The target body part in this plan can be the volunteer's heart, or other parts of the volunteer's body, such as the liver or stomach. This application does not limit the specific body part to be the target body part; it can be determined based on actual needs.

[0055] Step S102, according to the plurality of position information, respectively performing radio frequency transmission field local shimming on the plurality of target parts to respectively obtain the amplitude and phase of the transmission channel after local shimming, thereby obtaining a plurality of sets of the amplitude and phase of the transmission channel after local shimming of the radio frequency transmission field.

[0056] In the scheme, according to the position information, the region of the radio frequency transmission field local shimming is determined, thereby realizing the radio frequency transmission field local shimming on the target part.

[0057] In the scheme, the amplitude and phase are parameters of the transmission channel of the magnetic resonance device, and the amplitude and phase affect the amplitude and phase of the radio frequency pulse, and also affect the transmission sensitivity distribution of the transmission channel. The amplitude, that is, the amplitude, is usually used to represent the strength and power of the radio frequency signal, and the phase represents the angular offset between the radio frequency signals, and the phase is usually taken as a unit of "degree" or "radian". The amplitude and phase of the radio frequency signal affect the uniformity of the radio frequency signal pulse, and the uniformity of the radio frequency signal pulse causes the uniformity of the local spatial distribution of the radio frequency transmission field (B1 + ) and further affects the quality of the scan image.

[0058] In the scheme, the magnetic resonance device includes a plurality of transmission channels. For each target person, a corresponding set of amplitude and phase can be obtained after shimming. The set of amplitude and phase specifically includes the values of the amplitude and phase of the plurality of transmission channels of the magnetic resonance device. After shimming, a plurality of scanned persons can obtain a plurality of sets of amplitude and phase. Step S103, based on the plurality of sets of amplitude and phase of the transmission channel after local shimming of the radio frequency transmission field, obtaining a set of target amplitude and target phase of the transmission channel;

[0059] In the scheme, each target person corresponds to a set of amplitude and phase of the transmission channel after local shimming of the radio frequency transmission field. Through the plurality of sets of amplitude and phase of the transmission channel after local shimming of the radio frequency transmission field, a set of amplitude and phase of the transmission channel most meeting the requirements is obtained as the target amplitude and target phase.

[0060] Step S104, taking the target amplitude and target phase of the set of transmission channels as the initial amplitude and initial phase of the transmission channel for the next scan, scanning the target person to generate a target magnetic resonance image.

[0061] Specifically, the above-mentioned set of target amplitude and target phase of the transmission channel is taken as a parameter of the magnetic resonance image scanning system, that is, as the initial amplitude and initial phase of the transmission channel for the next scan, and the target person is scanned to generate a target magnetic resonance image.

[0062] In the scheme, by taking the amplitude and phase of the obtained most required transmission channel as the initial amplitude and initial phase of the transmission channel in the next scan, compared with the conventional scan on the target person by using the default amplitude and phase of the magnetic resonance device, the influence of the amplitude and phase of the radio frequency signal on the pulse uniformity of the radio frequency signal is relatively smaller in the scanning process, so that the influence of the pulse uniformity of the radio frequency signal on the uniformity of the local spatial distribution of the radio frequency transmission field (B1 + ) is relatively smaller, the local spatial distribution of the radio frequency transmission field is more uniform in the magnetic resonance image generation process, and thus the quality of the scan image and the accuracy of the clinical diagnosis are improved.

[0063] In an implementable manner, the step S101 specifically includes:

[0064] Based on a plurality of groups of the first magnetic resonance images, an image recognition model is used to obtain position information of a target part in each group of the first magnetic resonance images. The image recognition model is a model pre-trained by a large number of image samples, which outputs the geometric shape and position information of the target part after recognizing the target part.

[0065] In the scheme, the first magnetic resonance image is specifically obtained by scanning using a corresponding preset sequence by the magnetic resonance device, and the magnetic resonance device needs to be calibrated before scanning using the preset sequence. B1 + As a part of the calibration stage, a plurality of first magnetic resonance images can be generated by scanning at any stage before the shimming, and the target part is recognized and segmented using the first magnetic resonance images.

[0066] In the scheme, by using the image recognition model to obtain the position information of the target part in each group of the first magnetic resonance images, the position information of the target part is more accurate, so that the region of the local shimming of the radio frequency transmission field is more accurate, and the accuracy of the amplitude and phase of the transmission channel after the local shimming is obtained is ensured, and thus the uniformity of the spatial distribution of the radio frequency transmission field after the local shimming in the magnetic resonance image generation process is improved.

[0067] As shown in Figure 2 , in an implementable manner, the step 102 specifically includes:

[0068] Step S1021, obtaining a plurality of groups of second magnetic resonance images of a plurality of target persons;

[0069] In the scheme, each target person corresponds to a group of second magnetic resonance images, and each group of second magnetic resonance images can include a plurality of second magnetic resonance images. The second magnetic resonance image is an image used to obtain the transmission sensitivity of the transmission channel. The second magnetic resonance image includes the distribution information of the B1 + field map.

[0070] In step S1022, a plurality of sets of transmit sensitivities of the transmit channels are obtained based on the plurality of sets of the second magnetic resonance images; wherein the transmit sensitivity of the transmit channel can be represented by B1 + The field map characterizes.

[0071] In the present scheme, each target person corresponds to a set of second magnetic resonance images, and each set of second magnetic resonance images corresponds to a set of transmit sensitivities of the transmit channels.

[0072] In step S1023, a penalty function is used to calculate the target weight corresponding to the plurality of sets of transmit sensitivities of the transmit channels.

[0073] Specifically, the penalty function is calculated as shown in the following formula:

[0074]

[0075] Wherein J(w) represents the penalty function, the result of the penalty function represents the target weight corresponding to the transmit sensitivity of the transmit channel, S i represents the transmit sensitivity of the i-th transmit channel, T represents the optimization target value, w i represents the amplitude and phase of the i-th channel, which is a complex number; n represents the number of transmit channels, r represents the index of each point in the transmit sensitivity, R represents the number of points in the transmit sensitivity, and λ represents a constant greater than or equal to 0.

[0076] In step S1024, the amplitude and phase of the transmit channel after the local shimming of the plurality of sets of radio frequency transmit fields are obtained based on the target weight.

[0077] In the present scheme, the weight of the transmit sensitivity of the transmit channel is a complex number, which contains the amplitude and phase, so the target weight of each transmit channel sensitivity corresponds to the amplitude and phase of each transmit channel.

[0078] In the present scheme, the penalty function is used to calculate the target weight corresponding to the plurality of sets of transmit sensitivities of the transmit channels, so that the obtained target weight is more accurate, and then the amplitude and phase of the transmit channel after the local shimming of the plurality of sets of radio frequency transmit fields are obtained based on the target weight, so that the amplitude and phase of the transmit channel after the local shimming of the plurality of sets of radio frequency transmit fields are more accurate, and thus the local spatial distribution of the radio frequency transmit field in the magnetic resonance image generation process is ensured to be uniform.

[0079] In an implementable manner, before the step of using the penalty function to calculate the target weight of the plurality of sets of transmit sensitivities of the transmit channels, the step of locally shimming the radio frequency transmit field on the plurality of target sites to obtain the amplitude and phase of the transmit channel after the local shimming of the radio frequency transmit field further comprises:

[0080] applying a mask to the region outside the target region to obtain the amplitude and phase of the transmission channel after the local shimming of the radio frequency transmission field.

[0081] In this solution, by applying a mask to the region outside the target region, the target region can be more accurately subjected to local shimming of the radio frequency transmission field, thereby obtaining B1 + field map data, and finally, based on the transmission sensitivity of the transmission channel, the amplitude and phase of the transmission channel after the local shimming of the radio frequency transmission field are more accurately obtained.

[0082] Specifically, the step of applying a mask to the region outside the target region can be performed after the step of obtaining a plurality of sets of second magnetic resonance images generated by a plurality of target persons and before the step of obtaining the transmission sensitivity of a plurality of sets of transmission channels. Alternatively, the step of applying a mask to the region outside the target region can also be performed after the step of obtaining the transmission sensitivity of a plurality of sets of transmission channels and before the step of calculating the target weight corresponding to the transmission sensitivity of the plurality of sets of transmission channels using a penalty function. In summary, the step of applying a mask to the region outside the target region can be performed before the step of calculating the target weight of the plurality of sets of transmission channels using a penalty function.

[0083] In a specific embodiment, for example, when the target region is the heart, a mask is applied to the region outside the heart region, so that the amplitude and phase of the plurality of sets of transmission channels after local shimming of the radio frequency transmission field are more accurate, thereby ensuring the local spatial distribution uniformity of the radio frequency transmission field in the magnetic resonance image generation process.

[0084] As shown in Figure 3 In an implementable manner, the step S103 includes:

[0085] Step S1031, using the amplitude and phase of the transmission channel after local shimming of the plurality of sets of radio frequency transmission fields to scan a plurality of target persons to generate a plurality of sets of third magnetic resonance images.

[0086] Specifically, using the amplitude and phase of the transmission channel after local shimming of each set of radio frequency transmission fields to scan the corresponding target person to generate a set of third magnetic resonance images, so that using the amplitude and phase of the transmission channel after local shimming of the plurality of sets of radio frequency transmission fields to scan a plurality of target persons to generate a plurality of sets of third magnetic resonance images. The third magnetic resonance image is an image used to determine whether the amplitude and phase of the transmission channel meet the requirements, and the third magnetic resonance image can be a B1 + field map. The third magnetic resonance image can include structural information of the scanned object, and can also include B1 +Distribution information of the field map. The corresponding target personnel is the target personnel in step 101.

[0087] Step S1032, judging whether each group of the third magnetic resonance image meets the requirement, if yes, executing step S1033, if not, not considering the third magnetic resonance image that does not meet the requirement.

[0088] Specifically, the coefficient of variation of the target part in each group of the third magnetic resonance image is obtained, and it is judged whether the coefficient of variation is less than the preset threshold value, if less than the preset threshold value, the third magnetic resonance image meets the requirement.

[0089] Wherein, the coefficient of variation is the ratio of the standard deviation of the B1 + value of the field map and the average value of the B1 + value, the smaller the coefficient of variation, the better the uniformity of the B1 + field map of the third magnetic resonance image, that is, the better the local uniformity of the radio frequency transmit field of the target part. +

[0090] In the present scheme, by comparing the coefficient of variation of the target part in each group of the third magnetic resonance image with the preset threshold value as the judgment condition, it is ensured that the coefficient of variation meeting the requirement is screened, that is, the uniformity of the B1 + field map of the third magnetic resonance image is ensured, so as to ensure the accuracy of the candidate amplitude and candidate phase screened, and further ensure the local spatial distribution uniformity of the radio frequency transmit field in the magnetic resonance image generation process.

[0091] Step S1033, taking the amplitude and phase of the transmit channel corresponding to the third magnetic resonance image as the candidate amplitude and candidate phase of the transmit channel, respectively;

[0092] Step S1034, obtaining the candidate amplitude average value and candidate phase average value corresponding to the candidate amplitude and candidate phase, respectively, and taking the candidate amplitude average value and candidate phase average value as the target amplitude and target phase of a group of transmit channels, respectively.

[0093] In the present scheme, taking the candidate amplitude average value and candidate phase average value as the target amplitude and target phase of a group of transmit channels is only one preferred scheme, and other ways of obtaining the target amplitude and target phase can also be adopted according to the actual user needs, which is not limited herein.

[0094] In an implementable manner, the step S1034 specifically comprises:

[0095] Selecting the third magnetic resonance image with the coefficient of variation less than the preset threshold value;

[0096] ​constructing a histogram based on the amplitudes and phases corresponding to the third magnetic resonance images respectively;

[0097] based on the histogram, obtaining candidate amplitude mean value and candidate phase mean value corresponding to the candidate amplitudes and candidate phases.

[0098] Specifically, the third magnetic resonance image with the coefficient of variation less than the preset threshold is selected, that is, the third magnetic resonance image with low coefficient of variation is screened out, and a histogram is constructed according to the amplitude and phase of each channel thereof, wherein the phase is divided into intervals by α as an interval, and α represents a preset angle of the interval. The interval data with low density of each channel is screened out, the remaining interval phase and the amplitude corresponding thereto are averaged, and the calculated candidate amplitude mean value and candidate phase mean value are taken as the target amplitude and target phase of a group of transmission channels. In the present scheme, the histogram is constructed by using the amplitudes and phases corresponding to the third magnetic resonance images with the coefficient of variation less than the preset threshold to obtain the candidate amplitude mean value and candidate phase mean value corresponding to the candidate amplitudes and candidate phases, so as to ensure that the target amplitude and target phase of the optimal transmission channel are obtained, which are taken as the initial amplitude and initial phase of the transmission channel in the next scan, and the target person is scanned to generate a target magnetic resonance image, thereby improving the quality of the scanned image and the accuracy of the clinical diagnosis.

[0099] Taking the amplitude and phase screening of a certain transmission channel as an example, as shown in FIG. 1, Figure 4 The horizontal coordinate uniformly divides the amplitude value (0-1.0) into intervals, and every 0.1 is an interval, and the vertical coordinate represents the frequency of each interval, that is, the number of target persons falling into the corresponding interval amplitude. As can be seen from the figure, the frequency of the amplitude value in the (0.1-0.3) interval and the amplitude value in the (0.9-1.0) interval is very small, which is an interval with low data density, that is, the number of target persons falling into the (0.1-0.3) interval and the (0.9-1.0) interval is very small. Most of the data are concentrated in the (0.5-0.8) interval, which is an interval with high density, that is, the number of target persons falling into the (0.5-0.8) interval is large. In the calculation, the data in the low-density intervals, that is, the (0.1-0.3) interval and the (0.9-1.0) interval, are removed, and the amplitude in the remaining interval, that is, the (0.5-0.8) interval, is averaged, thereby obtaining a group of optimal target amplitudes and target phases of the transmission channel, which are taken as the initial amplitude and initial phase of the transmission channel in the next scan, thereby improving the quality of the scanned image and the accuracy of the clinical diagnosis.

[0100] Embodiment 2

[0101] As shown in FIG. 2, Figure 5As shown, the embodiment discloses a magnetic resonance image generation system for implementing the magnetic resonance image generation method of embodiment 1, which comprises:

[0102] The first acquisition module 1 acquires a plurality of groups of first magnetic resonance images of a plurality of target persons, and acquires position information of a target part in each group of the first magnetic resonance images based on the plurality of first magnetic resonance images;

[0103] The second acquisition module 2 is configured to locally shim the radio frequency transmission field for each of the target parts according to the plurality of position information to obtain the amplitude and phase of the transmission channel after local radio frequency transmission field shimming, and obtain a plurality of groups of the amplitude and phase of the transmission channel after local radio frequency transmission field shimming;

[0104] The third acquisition module 3 is configured to acquire target amplitude and target phase of a group of transmission channels based on the amplitude and phase of the plurality of groups of transmission channels after local radio frequency transmission field shimming;

[0105] The scanning module 4 is configured to use the target amplitude and target phase of the group of transmission channels as the initial amplitude and initial phase of the transmission channel for the next scan, and scan the target person to generate a target magnetic resonance image.

[0106] In an implementable manner, the second acquisition module 2 is further configured to:

[0107] Based on the plurality of groups of first magnetic resonance images, an image recognition model is used to acquire the position information of the target part in each group of the first magnetic resonance images.

[0108] As shown, in an implementable manner, the second acquisition module 2 specifically comprises: Figure 6

[0109] The first acquisition unit 21 is configured to acquire a plurality of groups of second magnetic resonance images of a plurality of target persons;

[0110] The second acquisition unit 22 is configured to acquire a plurality of groups of transmission channel transmission sensitivities based on the plurality of groups of second magnetic resonance images; wherein the transmission sensitivity of the transmission channel can be represented by B1 + field map.

[0111] The calculation unit 23 is configured to calculate target weights corresponding to the transmission sensitivities of the plurality of groups of transmission channels using a penalty function;

[0112] Specifically, the penalty function is calculated as shown in the following formula:

[0113]

[0114] ​Where J(w) represents the penalty function, the result of which represents the target weight corresponding to the transmission sensitivity of the transmission channel, and S i The transmit sensitivity of the i-th transmit channel is represented by T, and the target value is represented by w. i The amplitude and phase of the i-th channel are represented by complex numbers; n represents the number of transmission channels; r represents the index of each point in the transmission sensitivity; R represents the number of points in the transmission sensitivity; and λ represents a constant greater than or equal to 0.

[0115] The third acquisition unit 24 is used to acquire the amplitude and phase of the transmission channel after local homogenization of multiple sets of radio frequency transmission fields based on the target weight.

[0116] In one implementable manner, the second acquisition module 2 further includes:

[0117] The mask application unit 25 is used to apply a mask to the area outside the target area to obtain the amplitude and phase of the transmission channel after local homogenization of the radio frequency transmission field.

[0118] like Figure 7 As shown, in one implementable embodiment, the third acquisition module 3 includes:

[0119] Scanning unit 31 is used to scan multiple target personnel using the amplitude and phase of the transmission channels after local homogenization of multiple radio frequency transmission fields to generate multiple sets of third magnetic resonance images;

[0120] The judgment unit 32 is used to determine whether each group of the third magnetic resonance images meets the requirements. If yes, the first determination unit 33 is called. If no, the third magnetic resonance images that do not meet the requirements are not considered.

[0121] The first determining unit 33 uses the amplitude and phase of the emission channel corresponding to the third magnetic resonance image as candidate amplitude and candidate phase of the emission channel, respectively.

[0122] The second determining unit 34 obtains the average value of the candidate amplitude and the average value of the candidate phase corresponding to the candidate amplitude and the candidate phase, respectively, and uses the average value of the candidate amplitude and the average value of the candidate phase as the target amplitude and target phase of a set of transmission channels.

[0123] In one implementable manner, the determining unit 32 is specifically used for:

[0124] Obtain the coefficient of variation of the target region in the third magnetic resonance image generated by the amplitude and phase scan of the transmission channel after local shimming of the radio frequency transmission field for each group;

[0125] Determine whether the coefficient of variation is less than a preset threshold. If so, the third magnetic resonance image meets the requirements.

[0126] In an implementable manner, the first determining unit 33 is specifically configured to include:

[0127] selecting a third magnetic resonance image with a coefficient of variation less than a preset threshold value;

[0128] constructing a histogram based on the amplitude and phase corresponding to the third magnetic resonance image respectively;

[0129] obtaining candidate amplitude mean value and candidate phase mean value corresponding to the candidate amplitude and candidate phase based on the histogram.

[0130] Embodiment 3

[0131] Figure 8 A structural schematic diagram of an electronic device is provided in the embodiment of the present application. The electronic device includes a memory, a processor, and a computer program stored in the memory and used for running on the processor, and the processor implements the magnetic resonance image generation method provided in Embodiment 1 when executing the program. Figure 8 The electronic device 40 shown is merely an example and should not impose any limitation on the functions and use range of the embodiment of the present application.

[0132] As shown in Figure 8 The electronic device 40 can be in the form of a general computing device, for example, it can be a server device. The components of the electronic device 40 can include but are not limited to the above-mentioned at least one processor 41, the above-mentioned at least one memory 42, and a bus 43 connecting different system components including the memory 42 and the processor 41.

[0133] The bus 43 includes a data bus, an address bus, and a control bus.

[0134] The memory 42 can include volatile memory, such as random access memory (RAM) 421 and / or cache memory 422, and can further include read-only memory (ROM) 423.

[0135] The memory 42 can further include programs / utilities 425 having a set of (at least one) program modules 424, such as but not limited to an operating system, one or more application programs, other program modules, and program data, each of which or some combination of which can include the implementation of a network environment.

[0136] The processor 41 performs various functional applications and data processing by running the computer program stored in the memory 42, such as the magnetic resonance image generation method provided in Embodiment 1 of the present application.

[0137] The electronic device 40 can also communicate with one or more external devices 44 such as a keyboard, a pointing device, etc. through an input / output (I / O) interface 45. Further, the model generation device 40 can communicate with one or more networks such as a local area network (LAN), a wide area network (WAN), and / or a public network such as the Internet, through a network adapter 46. As pictured, the network adapter 46 communicates with the other modules of the model generation device 40 through the bus 43. It should be appreciated that other hardware and / or software modules can be used in conjunction with the model generation device 40 such as, but not limited to, microcode, device drivers, redundant processing units, external disk drive arrays, RAID (Redundant Array of Independent Disks) systems, tape drives, and data backup storage systems, etc. as depicted.

[0138] It should be noted that although several units / modules or sub-units / modules of an electronic device are mentioned in the foregoing detailed description, such a division is merely exemplary and not mandatory. Indeed, according to an embodiment of the application, the features and functionalities of two or more units / modules described above can be embodied in one unit / module. Conversely, the features and functionalities of one unit / module described above can be further divided into several units / modules embodied by.

[0139] Embodiment 4

[0140] The embodiment provides a computer readable storage medium, and a computer program is stored on the computer readable storage medium. The program is executed by a processor to implement the magnetic resonance image generation method provided in embodiment 1.

[0141] More specifically, the readable storage medium can include, but is not limited to, a portable disc, a hard disk, a random access memory, a read-only memory, an erasable programmable read-only memory, an optical storage device, a magnetic storage device, or any suitable combination of the above.

[0142] In a possible implementation, the application can also be implemented in the form of a program product, which includes program code for causing a terminal device to execute the magnetic resonance image generation method provided in embodiment 1 when the program product is run on the terminal device.

[0143] The program code for executing the application can be written in any combination of one or more programming languages, and can be executed entirely on the user device, partly on the user device and partly on a remote device, or entirely on a remote device, as a stand-alone software package, or partly on the user device and partly on a remote device.

[0144] Although the specific embodiments of the present application have been described above, it is understood by those skilled in the art that the present application is only illustrated by way of example, and the scope of protection of the present application is defined by the appended claims. Those skilled in the art can make various changes or modifications to the embodiments without departing from the principles and essence of the present application, and such changes and modifications fall within the scope of protection of the present application.

Claims

1. A method for generating magnetic resonance images, characterized in that, The generation method includes: Acquire multiple sets of first magnetic resonance images of multiple target individuals, and obtain the location information of the target part in each set of first magnetic resonance images based on the multiple sets of first magnetic resonance images; Based on multiple location information, local shimming of the radio frequency transmission field is performed on multiple target locations to obtain the amplitude and phase of the transmission channel after local shimming, thereby obtaining multiple sets of amplitude and phase of the transmission channel after local shimming of the radio frequency transmission field; Based on the amplitude and phase of the transmission channels after local homogenization of multiple sets of radio frequency transmission fields, the target amplitude and target phase of a set of transmission channels are obtained; The target amplitude and target phase of the set of transmission channels are used as the initial amplitude and initial phase of the transmission channels for the next scan to scan the target personnel and generate a target magnetic resonance image; The step of obtaining the target amplitude and target phase of a set of transmission channels based on the amplitude and phase of multiple sets of local homogenized radio frequency transmission fields includes: Multiple sets of third magnetic resonance images are generated by scanning multiple target personnel using the amplitude and phase of the transmission channels after local shimming of multiple radio frequency transmission fields; Obtain the coefficient of variation (COP) of the target region in each group of third magnetic resonance images. The COP is the coefficient of variation of the third magnetic resonance image. field map The standard deviation of the value The ratio of the average values; Select the third magnetic resonance image whose coefficient of variation is less than a preset threshold; Histograms are constructed based on the amplitude and phase corresponding to the third magnetic resonance image, respectively. Based on the histogram, the intervals with low data density and the intervals with high data density are determined. The average value of the candidate amplitude and the average value of the candidate phase corresponding to the interval with high data density are obtained, and the average value of the candidate amplitude and the average value of the candidate phase are respectively used as the target amplitude and target phase of a set of transmission channels.

2. The method for generating magnetic resonance images as described in claim 1, characterized in that, The step of obtaining the location information of the target region in each group of first magnetic resonance images based on multiple groups of first magnetic resonance images includes: Based on multiple sets of the first magnetic resonance images, the location information of the target part in each set of the first magnetic resonance images is obtained by using an image recognition model.

3. The method for generating magnetic resonance images as described in claim 1, characterized in that, The step of performing local shimming of the radio frequency transmission field on multiple target locations to obtain the amplitude and phase of the transmission channel after local shimming includes: Acquire multiple sets of second magnetic resonance images of multiple target individuals; Based on multiple sets of the second magnetic resonance images, the emission sensitivity of multiple emission channels is obtained; The target weights corresponding to the transmission sensitivity of the multiple sets of transmission channels are calculated using a penalty function; Based on the target weights, the amplitude and phase of the transmission channels after local homogenization of multiple sets of radio frequency transmission fields are obtained.

4. The method for generating magnetic resonance images as described in claim 3, characterized in that, Before the step of calculating the target weights corresponding to the transmission sensitivity of multiple transmission channels using a penalty function, the step of performing local RF transmission field shimming on multiple target locations to obtain the amplitude and phase of the transmission channels after local RF transmission field shimming further includes: A mask is applied to the area outside the target region to obtain the amplitude and phase of the transmission channel after local homogenization of the radio frequency transmission field.

5. A magnetic resonance image generation system, characterized in that, The generation system includes: The first acquisition module is used to acquire multiple sets of first magnetic resonance images of multiple target persons, and to acquire the location information of the target part in each set of first magnetic resonance images based on the multiple sets of first magnetic resonance images; The second acquisition module is used to perform local shimming of the radio frequency transmission field on the multiple target locations according to the multiple location information to obtain the amplitude and phase of the transmission channel after local shimming of the radio frequency transmission field, and to obtain multiple sets of amplitude and phase of the transmission channel after local shimming of the radio frequency transmission field. The third acquisition module is used to acquire the target amplitude and target phase of a set of transmission channels based on the amplitude and phase of the transmission channels after local homogenization of multiple sets of radio frequency transmission fields; The scanning module is used to use the target amplitude and target phase of the set of transmission channels as the initial amplitude and initial phase of the transmission channels for the next scan, and to scan the target personnel to generate a target magnetic resonance image; The third acquisition module includes: The scanning unit is used to scan multiple target personnel by using the amplitude and phase of the transmission channels after local shimming of multiple radio frequency transmission fields to generate multiple sets of third magnetic resonance images; The judgment unit is used to obtain the coefficient of variation of the target region in each group of third magnetic resonance images. The coefficient of variation is the coefficient of variation of the third magnetic resonance image. field map The standard deviation of the value The ratio of the average values; select the third magnetic resonance image whose coefficient of variation is less than a preset threshold; The first determining unit is used to construct histograms based on the amplitude and phase corresponding to the third magnetic resonance image, respectively; and to determine the intervals with low data density and the intervals with high data density based on the histograms. The second determining unit is used to obtain the average value of the candidate amplitude and the average value of the candidate phase corresponding to the interval with high data density, and respectively use the average value of the candidate amplitude and the average value of the candidate phase as the target amplitude and target phase of a set of transmission channels.

6. An electronic device comprising a memory, a processor, and a computer program stored in the memory and for running on the processor, characterized in that, When the processor executes the computer program, it implements the method for generating magnetic resonance images as described in any one of claims 1 to 4.

7. 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 method for generating magnetic resonance images as described in any one of claims 1 to 4.

Images