Vascular Imaging Method, Device, Electronic Device and Readable Storage Medium

Abstract

The present application discloses a vascular imaging method, apparatus, electronic device, and readable storage medium. The method includes: obtaining a plurality of echo images of an area of interest, where the plurality of echo images at least include a first echo image and a second echo image. Both the first echo image and the second echo image include vascular signals and background signals. The vascular signal intensity of the first echo image is greater than that of the second echo image, and the background signal intensity of the first echo image is greater than that of the second echo image. Performing region of interest fusion on the vascular signal of the first echo image and the background signal of the second echo image to obtain a target vascular image of the area of interest. According to the characteristics of high contrast and separability between blood vessels and the background, the present application recombines the vascular signals and background signals in time images with different signal intensities to optimize the image, with small computational complexity, high quality of the obtained vascular image, and strong practicability.

Description

Technical Field

[0001] This application relates to the field of medical technologies, and particularly to a method, apparatus, electronic device, and readable storage medium for vascular imaging. Background Art

[0002] Magnetic Resonance Imaging (MRI) is one of the main imaging modalities in modern medical imaging and has been widely used in medical imaging. Its basic principle is to utilize the magnetic resonance phenomenon, use radiofrequency excitation to excite hydrogen protons in the human body, use a gradient field for position encoding, then use a receiving coil to receive signals with position information, and finally reconstruct image information through Fourier transform.

[0003] In recent years, due to characteristics such as non-invasive and non-contrast enhancement, non-enhanced magnetic resonance angiography technology has become a risk-free imaging alternative to Computed Tomography Angiography (CTA) and Contrast-enhanced MR Angiography (CE-MRA), and has very important value in the clinical diagnosis of cardiovascular diseases. Among them, Time-of-Flight (TOF) MRA is one of the most commonly used vascular imaging technologies.

[0004] The three-dimensional imaging technology of TOF is widely used in the diagnosis of cerebrovascular diseases, such as intracranial occlusion, intracranial aneurysm, and arteriovenous malformation, etc., and is a conventional method for evaluating intracranial blood vessels. The principle of TOF is to utilize the magnetization intensity difference between flowing protons and stationary protons to achieve imaging contrast. Currently, TOF technology still has background tissues with relatively high signals, such as brain parenchyma and adipose tissue, and spin dephasing occurs in areas of curved blood vessels and fast blood flow, resulting in signal loss, thus making the blood vessels show unevenly (see Figure 1 ), and even false positives may occur in severe cases. Summary of the Invention

[0005] To solve the above problems, embodiments of this application provide a method, apparatus, electronic device, and readable storage medium for vascular imaging.

[0006] In a first aspect, a method for vascular imaging is provided, and the method includes:

[0007] Obtain a plurality of echo images of the region of interest, where the plurality of echo images at least include a first echo image and a second echo image, where both the first echo image and the second echo image include vascular signals and background signals, the vascular signal intensity of the first echo image is greater than that of the second echo image, and the background signal intensity of the first echo image is greater than that of the second echo image;

[0008] Perform region of interest fusion on the vascular signal of the first echo image and the background signal of the second echo image to obtain the target vascular image of the region of interest.

[0009] In a second aspect, there is provided a vascular imaging device, the device comprising:

[0010] An acquisition unit, configured to acquire a plurality of echo images of the region of interest, where the plurality of echo images at least include a first echo image and a second echo image, where both the first echo image and the second echo image include vascular signals and background signals, the vascular signal intensity of the first echo image is greater than that of the second echo image, and the background signal intensity of the first echo image is greater than that of the second echo image;

[0011] A fusion unit, configured to perform region of interest fusion on the vascular signal of the first echo image and the background signal of the second echo image to obtain the target vascular image of the region of interest.

[0012] In a third aspect, an embodiment of the present application further provides an electronic device, comprising: a processor; and a memory arranged to store computer-executable instructions, where the executable instructions, when executed, cause the processor to execute any of the above methods.

[0013] In a fourth aspect, an embodiment of the present application further provides a computer-readable storage medium, where the computer-readable storage medium stores one or more programs, and when the one or more programs are executed by an electronic device including a plurality of application programs, the electronic device is caused to execute any of the above methods.

[0014] At least one of the above technical solutions adopted in the embodiments of the present application can achieve the following beneficial effects:

[0015] In the process of nuclear magnetic resonance imaging based on time-of-flight (TOF), this application utilizes image processing technology. Based on the idea of information sharing and exchange recombination, in the form of multi-image fusion, it performs region-of-interest (ROI) fusion on multiple echo images of multiple regions of interest to obtain a target vascular image with strong contrast and ideal effects. The target vascular image has uniform and clear blood vessels, as well as a background that is clean, dark, and has weak interference with the blood vessels. According to the characteristics of high contrast and separability between the blood vessels and the background, this application recombines the blood vessel signals and background signals in time images with different signal intensities to achieve image optimization, with small computational complexity, high-quality obtained vascular images, and strong practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings described herein are used to provide a further understanding of this application and form a part of this application. The schematic embodiments of this application and their descriptions are used to explain this application and do not constitute an improper limitation to this application. In the drawings:

[0017] Figure 1 shows an image of vascular imaging obtained by using the conventional TOF technology in the prior art;

[0018] Figure 2 shows a schematic flowchart of a vascular imaging method according to an embodiment of this application;

[0019] Figure 3 shows a sequence diagram within one repetition time unit (TR) during the nuclear magnetic resonance process;

[0020] Figure 4 shows a maximum intensity projection (MIP) map obtained by using the conventional TOF technology according to the prior art;

[0021] Figure 5 shows echo images collected at three different echo times of the same section (i.e., the same layer) according to an embodiment of this application;

[0022] Figure 6 shows a schematic diagram of the ROI fusion process between the first echo image and the second echo image according to an embodiment of this application;

[0023] Figure 7 shows a schematic flowchart of a vascular imaging method according to another embodiment of this application;

[0024] Figure 8 shows a schematic flowchart of a vascular imaging method according to still another embodiment of this application;

[0025] Figure 9 shows a schematic diagram of obtaining an optimized target vascular image by performing non-linear transformation on different profiles of the target vascular image according to an embodiment of this application;

[0026] Figure 10 Shows the target vessel images of four slices according to an embodiment of the present application;

[0027] Figure 11 Shows the MIP maps of the cross-section (11-(a)), coronal plane (11-(b)), and sagittal plane (11-(c)) obtained by using the vessel imaging method of the present application;

[0028] Figure 12 Shows a schematic structural diagram of a vessel imaging device according to an embodiment of the present application;

[0029] Figure 13 Is a schematic structural diagram of an electronic device in an embodiment of the present application. Detailed implementation manners

[0030] To make the objectives, technical solutions, and advantages of the present application clearer, the technical solutions of the present application will be clearly and completely described below in conjunction with the specific embodiments of the present application and the corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0031] The following will describe in detail the technical solutions provided by each embodiment of the present application in conjunction with the drawings.

[0032] Time of flight (TOF) is one of the commonly used imaging techniques in nuclear magnetic resonance. The conventional TOF three-dimensional imaging gradient echo sequence consists of a presaturation pulse and a gradient echo sequence with first-order flow compensation. The purpose of adding the presaturation pulse is to achieve separate imaging of arteries and veins, and the first-order flow compensation is to compensate for the additional phase brought by the uniform motion of blood. The repeated radiofrequency excitation pulses in the gradient echo sequence can saturate the longitudinal magnetization vector of static tissues. However, due to the inflow enhancement effect, especially when the arterial blood flow velocity is relatively large, blood is not easily saturated, thus generating signal contrast.

[0033] TOF is essentially T1 (time of appearance) weighted imaging. Substances with short T1, such as fat, will exhibit relatively high signals, affecting the contrast of vessel imaging, especially prone to artifacts in the Maximum Intensity Projection (MIP) image.

[0034] In the prior art, in order to reduce signal loss and artifacts caused by blood movement, there are usually two methods. First, in clinical scans, the first-order flow compensation method is generally used to reduce the phase dispersion of blood flow signals. To suppress the brighter fat signal, the TE (echo time) is set to the time when the transverse magnetization vectors of water and fat are completely opposite, that is, in a 1.5T magnetic resonance system and with flow compensation, the TE can generally only be selected as the longer water-fat phase inversion time, such as 6.9 ms. During the MIP process, in order to prevent the image from being affected by the edge fat signal, manual image cropping can be selected, and MIP is only performed on the signals near the blood vessels. This method only reduces the influence of motion phase dispersion from the perspective of flow compensation, and the imaging quality in areas with complex flow still cannot be guaranteed.

[0035] Second, since the first-order flow compensation cannot compensate for the phase dispersion and signal loss caused by higher-order motion. Usually, a short TE can replace flow compensation and even further reduce this phase dispersion, making the blood vessels appear more uniform. Using the shortest possible echo time (Echo Time, TE) can effectively reduce spin phase dispersion, but the background signal will also increase accordingly. In order to obtain both good blood vessel signals and good image contrast, another solution is to combine a short TE with a fat suppression module. This method adds a fat suppression module, which will increase the imaging time required, and there are still certain risks for the existing fat suppression methods in TOF imaging, which may lead to false positives.

[0036] The concept of this application is that, in view of the above situation, this application uses the echo images of multiple regions of interest. Each of the multiple echo images includes blood vessel signals and background signals, and the intensities of the blood vessel signals and background signals in each echo image are different. By fusing the strong blood vessel signals with the weak background signals in the region of interest, a bright and uniform blood vessel image can be obtained, and an overall image with background suppression can be obtained, thereby obtaining an image with high contrast and good display effect.

[0037] Figure 2 The flowchart of the blood vessel imaging method according to an embodiment of this application is shown. From Figure 2 It can be seen that this application at least includes steps S210 to S220:

[0038] Step S210: Obtain multiple echo images, and obtain multiple echo images of the region of interest. Among them, the multiple echo images at least include a first echo image and a second echo image. The first echo image and the second echo image both include blood vessel signals and background signals. The intensity of the blood vessel signal in the first echo image is greater than that in the second echo image, and the intensity of the background signal in the first echo image is greater than that in the second echo image.

[0039] The imaging in nuclear magnetic resonance using the time-of-flight method utilizes a spoiled gradient echo sequence, such asFigure 3 As shown Figure 3 shows a sequence diagram within a repetition time unit (TR) during nuclear magnetic resonance. The time from the emission of the radio frequency excitation pulse to the acquisition center time is the echo time TE. From Figure 3 It can be seen that using Figure 3 this sequence, (Kx * 3) data points are collected each time, and it is continuously repeated Kz * Ky times. Each time, the values of Ky and Kz are different. This is the encoding process. Finally, three-dimensional K-space data (Kx, Ky, Kz) corresponding to each echo can be obtained. After Fourier transform, the image of each echo is obtained. From Figure 3 it can be seen that multiple echo images can be obtained according to different echo times.

[0040] Due to the complexity of blood flow in blood vessels, such as the existence of turbulence and other phenomena, the longer the time interval (TE) from the excitation of the radio frequency excitation pulse to the acquisition, the more severe the loss of blood signal. Therefore, the shorter the TE, the brighter and more uniform the blood vessel signal collected. That is to say, in the first echo image, the blood vessels are the brightest and most uniform. In this embodiment, in the echo image with the shortest echo time (TE1), the blood vessel signal intensity is the highest. Here, it is denoted as the first echo image. In the following embodiments, the echo image with the shortest echo time (TE1) is used as the first echo image. It should be noted that the first echo image is not limited to the echo image with the shortest echo time (TE1). Any image with a high blood vessel signal intensity, that is, a good blood vessel imaging effect, can be used as the first echo image.

[0041] In addition to considering the blood vessels themselves, the strength of the background signal also has a great impact on the image quality and directly affects the image contrast. Taking the MIP image as an example, the MIP image is composed of the maximum values of pixel signals in the projection direction. As Figure 4 shown, the MIP image projected along the arrow direction comes from the maximum value projection of the signals in this direction. If the background signal is very strong, such as Figure 4 the fat signal marked by the arrow in, this signal is the maximum signal in this projection direction. Corresponding to the MIP image, a brighter background will be obtained, resulting in a low contrast of the MIP image and even masking the small blood vessel signals that are not bright enough. Therefore, it is very necessary to suppress the background signal in blood vessel imaging.

[0042] Therefore, when selecting the second echo image, a darker background image is selected. For stationary background signals, especially the fat signal around the scalp, it is not that the shorter the TE, the better, but the longer the TE, the better. As Figure 5 shown Figure 5 shows echo images collected at three different echo times of the same section (i.e., the same layer) according to an embodiment of the present application. From Figure 5 it can be seen that byFigure 5 -(a), Figure 5 -(b) and Figure 5 -(c), it can be seen by comparison that Figure 5 -the background in (c) is relatively dark, Figure 5 -the second echo image as the background signal source in (c) is very good. In the following embodiments, the echo image with the longest echo time is used as the second echo image. The time of this echo (6.9 ms) is the image with the longest echo time, and it is exactly the time when the water and fat phase directions are opposite. For suppressing the background signal, the echo time shown in 5-(c) is 6.9 ms, that is, the image with the longest echo time is the best. Similarly, the second echo image is not limited to the echo image with the longest echo time, and any image with a greater degree of background suppression can be used.

[0043] In summary, when selecting the echo image, it is sufficient to select according to the requirement that the vascular signal intensity of the first echo image is greater than the vascular signal intensity of the second echo image, and the background signal intensity of the first echo image is less than the background signal intensity of the second echo image.

[0044] In this application, the images are all represented in the form of sequences. In the following description, "image" and "sequence" are the same concept; in the embodiments of this application and each drawing, the shortest echo time is 2.37 ms, and the longest echo time is 6.9 ms. This is only for illustrative purposes and does not form any limitation to this application.

[0045] Step S220: Perform region of interest fusion on the vascular signal of the first echo image and the background signal of the second echo image to obtain the target vascular image of the region of interest.

[0046] As mentioned above, in the first echo image, the effect of blood vessels is relatively good. Therefore, the region of interest of the first echo image is blood vessels; in the second echo image, the effect of background suppression is relatively good. Therefore, the region of interest of the second echo image is the background. By fusing the blood vessels in the first echo image with the background in the second echo image, an image containing the target blood vessels with an ideal effect can be obtained.

[0047] Regarding the region of interest fusion technology, this application does not make any restrictions. One or several combinations of image processing technologies in the prior art can be referred to. For example, first, the region of interest can be extracted through feature extraction technology, and then co-location fusion can be performed to obtain the target vascular image with an ideal effect.

[0048] From Figure 1It can be seen that in the nuclear magnetic resonance imaging process based on time-of-flight method, the present application uses image processing technology. Based on the idea of information sharing and exchange and recombination, in the form of multi-image fusion, the region of interest fusion is performed on multiple echo images of multiple regions of interest to obtain a target vascular image with strong contrast and ideal effect. The target vascular image has uniform and clear blood vessels, and a background that is clean, dark, and has weak interference with blood vessels. According to the characteristics of high contrast and separability between blood vessels and the background, the present application recombines the blood vessel signals and background signals in time images with different signal intensities to optimize the image, with small computational amount, high quality of the obtained vascular image, and strong practicability.

[0049] In some embodiments of the present application, the first echo image is the echo image with the shortest echo time within one repetition time unit in the nuclear magnetic resonance imaging process based on time-of-flight method; the second echo image is the echo image with water-fat phase inversion within the one repetition time unit.

[0050] In some embodiments of the present application, at least the first echo image with the shortest echo time and the second echo image with the longest echo time within one repetition time unit in the nuclear magnetic resonance imaging process based on time-of-flight method are included in the multiple echo images. When TE is short, the blood vessels in the acquired image are brighter and more uniform, and the imaging effect of blood vessels in the first echo image is the best; in the image with the longest echo time, the water and fat are in opposite phases, and the background is suppressed to the greatest extent. Based on image processing technology, fusing the blood vessels in the first echo image with the background in the second echo image can obtain an image with high contrast and good display effect.

[0051] For the image fusion step in step S220, it can also be implemented by any one of the following two recommended methods in the present application. The first method, the region of interest fusion of the first echo image and the second echo image to obtain a target vascular image, includes: step S221: extracting a foreground sequence from the first echo image according to the multiple echo images, the foreground sequence includes the blood vessel signals of the first echo image, and in the foreground sequence, the pixel points corresponding to the blood vessel signals in the first echo image are non-zero pixel points; and step S222: fusing the foreground sequence with the second echo image to obtain a target vascular image.

[0052] Among them, the foreground sequence is a sequence containing the target blood vessels, that is, extracting the foreground sequence containing the target blood vessels from the first echo image, and then replacing the values at the same positions as the foreground sequence in the second echo image with the foreground sequence to achieve the fusion effect.

[0053] In step S221, extracting the foreground sequence from the first echo image according to the multiple echo images includes: determining a first mask of the target blood vessel according to the intensity of each pixel point of the second echo image; extracting the pixel points corresponding to the blood vessel signal in the first echo image according to the first mask to obtain the foreground sequence.

[0054] In step S221, fusing the foreground sequence with the second echo image to obtain a target blood vessel image includes: assigning non-zero pixel points in the foreground sequence to corresponding positions in the second echo image; using the second echo image after assignment as the target blood vessel image.

[0055] A mask can be understood as a sequence composed of 0 and 1, and can be in the form of a vector or a matrix. Since the images involved in this application are all binary images, therefore, the echo images in this application are usually two-dimensional matrices, and the shapes of the echo images are usually the same. For example, both the first echo image and the second echo image are matrices of 512*512.

[0056] To extract the image containing the target blood vessel from the first echo image, it is first necessary to determine the mask of the target blood vessel, denoted as the first mask. Since the contrast between the blood vessel and the background is obvious in the second echo image, the first mask can be determined according to the intensity of each pixel point in the second echo image. Then, a specified operation is performed between the first echo image and the first mask, that is, according to the first mask, the pixel points of the blood vessel signal in the first echo image are extracted to obtain the foreground sequence; then the foreground sequence is correspondingly replaced in the second echo image to obtain the target blood vessel image.

[0057] Please refer to Figure 6 , Figure 6 shows a schematic diagram of the process of fusing the region of interest in the first echo image with the second echo image in an embodiment of the present application. Figure 6 6-(a) in represents the first echo image, each square represents a pixel point of the first echo image, and the "√" in the pixel point represents the value of each pixel point, and the values of each pixel point are all non-zero; 6-(b) represents the second echo image, each square represents a pixel point of the second echo image, and the "×" in the pixel point represents the value of each pixel point, and the values of each pixel point are all non-zero; 6-(c) represents the first mask of the target blood vessel, each square represents a pixel point of the first mask, the first mask includes two elements of "0" and "1", and the pixel points with 1 in the first mask represent the positions of the target blood vessels. Among them, the first mask can be determined according to the intensity of each pixel point in the second echo image.

[0058] Performing a "multiplication" operation on the first echo image and the first mask can obtain the foreground sequence. As shown in 6-(d) of the figure, after the first echo image is operated with the first mask, the foreground sequence is obtained. In the foreground sequence, the pixel points at the target blood vessel positions maintain their original values, while the pixel points at other positions are set to 0.

[0059] Then, the foreground sequence is fused with the second echo image. Specifically, direct in-place replacement can be performed, that is, the non-zero pixel points in the foreground sequence are assigned to the corresponding positions in the second echo image, obtaining the sequence shown in 6-(e) of the figure, which is the target blood vessel image.

[0060] In some embodiments of the present application, in the above method, determining the first mask of the target blood vessel according to the intensities of the pixel points of the second echo image includes: obtaining the maximum value of the intensities of the pixel points of the second echo image; setting an intensity threshold according to the maximum value; if the intensity of a pixel point in the second echo image is greater than the intensity threshold, then taking this pixel point as a non-zero pixel point of the first mask; and determining the first mask according to the determined multiple non-zero pixel points.

[0061] In the second echo image, since the background formed by fat is very dim, relatively speaking, the signal intensity contrast between the blood vessels and the background is greater than that of the first echo image. Therefore, the intensities of the pixel points in the second echo image can be used to determine the first mask. Specifically, an intensity threshold is set according to the intensities of the pixel points in the second echo image. If the intensity of a pixel point is above this intensity threshold, then this pixel point is considered to belong to the first mask. The intensity threshold can be determined according to the maximum value of the intensities of the pixel points in the second echo image. After obtaining the maximum value of the intensities of the pixel points in the second echo image, dividing the maximum value by a value greater than 1, such as 1.3, and taking the obtained value as the intensity threshold. Taking this pixel point as a non-zero pixel point of the first mask, the value of the non-zero pixel point is usually 1. If the intensity of a pixel point is less than this intensity threshold, then setting the value of this pixel point to 0. Performing the above processing on each pixel point in the second echo image can obtain the first mask, as shown in 6-(c) of the figure. Figure 6 as shown in 6-(c) of the figure.

[0062] In some embodiments of the present application, determining the first mask of the target blood vessel according to the intensities of the pixel points of the second echo image further includes: performing multi-layer convolution processing on the first mask with a specified matrix, where the specified matrix is a matrix of all 1s, and the size of the specified matrix is determined according to the size of the first mask; determining the union of the masks obtained in each layer of the multi-layer convolution, and taking the union as the first mask of the target blood vessel.

[0063] Due to severe signal dispersion of local blood vessels, some blood vessel information may be below the threshold. Therefore, the non-zero pixel points in the first mask may not be continuous. To solve this problem, the first mask can be convolved with a all-ones matrix A, such as a 20*20 all-ones matrix, which can make the first mask smoother. The specific expression can be: mask_first = conv2(mask_first, A,'same') > 0.

[0064] In addition, for the mask obtained by the above threshold method, there may also be a problem of discontinuous coordinates in the layer direction. Therefore, the first mask of each layer (section) can integrate the masks of several adjacent layers and take the union of the masks of these layers to obtain the final first mask.

[0065] Figure 7 FIG. shows a schematic flowchart of a blood vessel imaging method according to another embodiment of the present application. Figure 7 As can be seen, this embodiment includes:

[0066] Obtain a first echo image, which is the image with the shortest echo time within a repetition time unit during the nuclear magnetic resonance imaging based on the time-of-flight method.

[0067] Obtain a second echo image, which is the image with the longest echo time within a repetition time unit during the nuclear magnetic resonance imaging based on the time-of-flight method; obtain the intensity values of each pixel point in the second echo image, determine the maximum intensity value, and set the intensity threshold according to the maximum intensity value.

[0068] Judge whether the intensity value of a pixel point in the second echo image is greater than the intensity threshold. If so, set the value of this pixel point in the first mask of the target blood vessel to 1. If not, set the value of this pixel point in the first mask of the target blood vessel to 0, and determine the first mask according to the values of each pixel point in the first mask.

[0069] Perform a first specified operation on the first echo image and the first mask to obtain a foreground sequence.

[0070] Assign the values of the non-zero pixel points in the foreground sequence to the second echo image, and use the second echo image as the target blood vessel image.

[0071] In some embodiments of the present application, the multiple echo images further include a third echo image, the third echo image includes vascular signals and background signals, and the background signal of the third echo image is greater than the background signal intensity of the second echo image; for the image fusion step in step S220, another implementation manner may be adopted. Specifically, the step of fusing the region of interest in the first echo image with the second echo image to obtain a target vascular image includes: extracting a background sequence from the second echo image according to the intensity difference of each pixel point in the second echo image and the third echo image; and fusing the background sequence with the first echo image to obtain a target vascular image.

[0072] Wherein, the third echo image includes vascular signals and background signals, and the background signal of the third echo image is greater than the background signal intensity of the first echo image. That is to say, among the multiple echo images, the background signal of the third echo image is the strongest, and the background signal intensity of the second echo image is the weakest. Thus, a more accurate background sequence can be extracted according to the intensity difference of each pixel point in the second echo image and the third echo image.

[0073] In some embodiments of the present application, the third echo image is an echo image with the same water-fat phase as that in the same repetition time unit where the first echo image and the second echo image are located.

[0074] Please refer to Figure 3 , in Figure 3 , the image with the echo time between the first echo image and the second echo image is an image with the same water-fat phase. In the present application, its echo time is 4.9 ms, which is close to the time of the same water-fat phase, and will enhance the water-fat signal. For the background signal, the difference between the second echo image and the third echo image is the largest, corresponding to the opposite water-fat phase and the same water-fat phase respectively. Therefore, this difference can be used to determine the second mask of the background, and thus determine the background sequence in the second echo image. The background sequence includes the background signal of the second echo image. In the background sequence, the pixel points at the corresponding positions of the background signal of the second echo image are non-zero pixel points. Then, the corresponding background sequence is replaced into the first echo image to obtain the target vascular image. Therefore, an echo image with the same water-fat phase can be selected as the third echo image. The specific process is similar to the embodiment shown in Figure 6 .

[0075] For the extraction process of the background sequence, the specific process can refer to the following flow. According to the intensity difference of each pixel point in the second echo image and the third echo image, extracting the background sequence from the second echo image includes: determining a second mask for the fat background according to the intensity difference of each pixel point in the second echo image and the third echo image; performing a second specified operation on the second echo image and the second mask, that is, according to the second mask, extracting the pixel points of the background signal in the second echo image to obtain the background sequence. Fusing the background sequence with the first echo image to obtain the target blood vessel image includes: assigning the non-zero pixel points in the background sequence to the corresponding positions in the first echo image; using the first echo image after being assigned as the target blood vessel image.

[0076] For the determination method of the corresponding second mask, it can be determined according to the difference in the intensity of each pixel point between the third echo image and the second echo image. Determine the difference in the intensity of each pixel point between the third echo image and the second echo image one by one, and set an intensity difference threshold. If the intensity difference of a pixel point is greater than the intensity difference threshold, it is determined that the pixel point belongs to the second mask, and the value of the pixel point is set to 1. If the intensity difference of a pixel point is not greater than the intensity difference threshold, it is determined that the pixel point does not belong to the second mask, and the value of the pixel point is set to 0, thereby obtaining the second mask. In the second mask, the positions of the non-zero pixel points represent the positions of the background.

[0077] Perform a second specified operation on the second echo image and the second mask. In the embodiment of the present application, since in the second mask, the value of the pixel point representing the position of the background is 1, and the value of the pixel point representing the position of the blood vessel is 0, the second specified operation can be a multiplication operation. After the operation, the background sequence is obtained. In the background sequence, the values of the pixel points representing the positions of the background retain the original values in the second echo image, and the values of the remaining pixel points are set to 0.

[0078] Then assign the values of the non-zero pixel points in the background sequence to the corresponding positions of the first echo image, and use the first echo image after being assigned as the target blood vessel image.

[0079] It should be noted that the forms of the first mask and the second mask are not limited to the examples listed above. If the forms of the first mask and the second mask change, the first specified operation and the second specified operation also need to be adjusted accordingly.

[0080] Figure 8 shows a schematic flowchart of a blood vessel imaging method according to another embodiment of the present application. From Figure 8 it can be seen that this embodiment includes:

[0081] Obtain a first echo image, where the first echo image is the image with the shortest echo time within a repetition time unit during nuclear magnetic resonance imaging based on the time-of-flight method; obtain a second echo image, where the second echo image is the image with water-fat phase inversion within a repetition time unit during nuclear magnetic resonance imaging based on the time-of-flight method; obtain a third echo image, where the third echo image is the image with water-fat phase alignment within a repetition time unit during nuclear magnetic resonance imaging based on the time-of-flight method.

[0082] Obtain the intensity values of each pixel point in the third echo image and the intensity values of each pixel point in the second echo image, and the difference between the intensity values of each pixel point; determine whether the difference between the intensity values of a pixel point is greater than a preset intensity difference threshold. If so, set the value of this pixel point in the second mask of the background to 1. If not, set the value of this pixel point in the second mask of the background to 0, and determine the second mask according to the values of each pixel point in the first mask.

[0083] Perform a second specified operation on the second echo image and the second mask to obtain a background sequence.

[0084] Assign the non-zero pixel point values in the background sequence to the first echo image, and use the first echo image as the target vessel image.

[0085] In some embodiments of the present application, the method further includes: performing an exponential transformation on the obtained target vessel image based on the following formula to obtain an optimized target vessel image:

[0086] image new =(1-(a*image+e -image )) b ;

[0087] where, image new is the optimized target vessel image, the image is the target vessel image, a = 0.4, b = 2.

[0088] After transformation using the above formula, at the same window width and window level, compared with the image before transformation, the vessel uniformity of image new is significantly improved.

[0089] Figure 9 shows a schematic diagram of obtaining an optimized target vessel image by non-linearly transforming different profiles of the target vessel image according to an embodiment of the present application. From Figure 9 of Figure 9 -(a), Figure 9 -(b) and Figure 9It can be seen from (c) that the non - linear transformation does not affect the diagnosis of vascular stenosis, and can significantly improve the brightness and uniformity of blood vessels. The vascular images of nearly 10 different volunteers were processed with this transformation, and it was found that the algorithm is robust enough and does not even require adjusting the magnitudes of parameters a and b.

[0090] Figure 10 The target vascular images of four slices according to an embodiment of the present application are shown. For each slice, the right - most figure represents the first - echo image with TE = 2.37 ms, and the left - most figure represents the second - echo image with TE = 6.9 ms. The middle image is obtained by replacing the vascular signal in the right - hand figure into the left - hand figure, and it shows an image of the blood vessel with high uniformity and contrast.

[0091] Figure 11 The MIP maps of the cross - section (11-(a)), coronal plane (11-(b)), and sagittal plane (11-(c)) obtained by using the vascular imaging method of the present application are shown. From Figure 11 It can be seen that the one labeled TE = 2.37 is the first - echo image, the one labeled TE = 6.9 is the second - echo image, and the one labeled algorithm synthesis is the MIP map of the cross - section, coronal plane, and sagittal plane obtained by using the vascular imaging method of the present application. From Figure 11 It can be seen that the present application perfectly combines the uniform blood vessels with short TE and the suppressed background with long TE.

[0092] In the above - mentioned embodiment of the present application, the first - echo image and the second - echo image are subjected to region - of - interest fusion, that is, the vascular signal in the first - echo image and the background signal in the second - echo image are fused. Here, the vascular signal and the background signal can be understood as the pixel points at the corresponding positions in the image, and the absolute intensity of the pixel points is used.

[0093] Figure 12 The structural schematic diagram of a vascular imaging device according to an embodiment of the present application is shown. From Figure 12 It can be seen that the vascular imaging device 1200 includes:

[0094] An acquisition unit 1210, configured to acquire a plurality of echo images of an interested region, where the plurality of echo images at least include a first - echo image and a second - echo image. Both the first - echo image and the second - echo image include a vascular signal and a background signal. The vascular signal intensity of the first - echo image is greater than that of the second - echo image, and the background signal intensity of the first - echo image is less than that of the second - echo image;

[0095] A fusion unit 1220, configured to perform region - of - interest fusion on the vascular signal of the first - echo image and the background signal of the second - echo image to obtain a target vascular image of the interested region.

[0096] In some embodiments of the present application, in the above-mentioned device, the first echo image is the echo image with the shortest echo time within one repetition time unit during the nuclear magnetic resonance imaging based on the time-of-flight method; the second echo image is the echo image with the same water-fat phase and opposite magnetization vectors within the one repetition time unit.

[0097] In some embodiments of the present application, in the above-mentioned device, the fusion unit 1220 is configured to extract a foreground sequence from the first echo image according to the plurality of echo images; fuse the foreground sequence with the second echo image to obtain the target vascular image of the region of interest.

[0098] In some embodiments of the present application, in the above-mentioned device, the fusion unit 1220 is configured to determine a first mask of the target blood vessel according to the intensity of each pixel point of the second echo image; perform a first specified operation on the first echo image and the first mask to obtain the foreground sequence.

[0099] In some embodiments of the present application, in the above-mentioned device, the fusion unit 1220 is configured to obtain the maximum value of the intensity of each pixel point of the second echo image; set an intensity threshold according to the maximum value; if the intensity of a pixel point in the second echo image is greater than the intensity threshold, then use this pixel point as a non-zero pixel point of the first mask; determine the first mask according to the determined plurality of non-zero pixel points.

[0100] In some embodiments of the present application, in the above-mentioned device, the fusion unit 1220 is configured to perform multi-layer convolution processing on the first mask with a specified matrix, where the specified matrix is a matrix of all 1s, and the size of the specified matrix is determined according to the size of the first mask; determine the union of the masks obtained in each layer of the multi-layer convolution and use the union as the first mask of the target blood vessel.

[0101] In some embodiments of the present application, in the above-mentioned device, the fusion unit 1220 is configured to assign non-zero pixel points in the foreground sequence to corresponding positions in the second echo image; use the second echo image after assignment as the target vascular image of the region of interest.

[0102] In some embodiments of the present application, in the above-mentioned device, the multiple echo images further include a third echo image, the third echo image includes a vascular signal and a background signal, and the background signal of the third echo image is greater than the background signal intensity of the first echo image; a fusion unit 1220, configured to extract a background sequence from the second echo image according to the intensity difference of each pixel point in the second echo image and the third echo image; and fuse the background sequence with the first echo image to obtain a target vascular image of the region of interest.

[0103] In some embodiments of the present application, in the above-mentioned device, the third echo image is an echo image with water-fat phase inversion and the same magnetization vector within the same repetition time unit as the first echo image and the second echo image.

[0104] In some embodiments of the present application, in the above-mentioned device, the fusion unit 1220 is configured to determine a second mask of the fat background according to the intensity difference of each pixel point in the second echo image and the third echo image; and perform a second specified operation on the second echo image and the second mask to obtain the background sequence.

[0105] In some embodiments of the present application, in the above-mentioned device, the fusion unit 1220 is configured to assign non-zero pixel points in the background sequence to corresponding positions in the first echo image; and use the first echo image after being assigned as the target vascular image.

[0106] In some embodiments of the present application, in the above-mentioned device, the fusion unit 1220 is further configured to perform an e-exponential transformation on the obtained target vascular image based on the following formula to obtain a target vascular optimized image:

[0107] image new =(1-(a*image+e -image )) b ;

[0108] wherein, image new is the target vascular optimized image, the image is the target vascular image, a = 0.4, b = 2.

[0109] It should be noted that the above-mentioned vascular imaging device can implement the foregoing vascular imaging method one by one, which will not be elaborated here.

[0110] Figure 13 is a schematic structural diagram of an electronic device according to an embodiment of the present application. Please refer to Figure 13, at the hardware level, the electronic device includes a processor, and optionally also includes an internal bus, a network interface, and a memory. Among them, the memory may include a memory, such as a high-speed random access memory (Random-Access Memory, RAM), and may also include a non-volatile memory, such as at least one disk memory, etc. Of course, the electronic device may also include other hardware required for other services.

[0111] The processor, network interface, and memory can be interconnected through the internal bus. The internal bus can be an ISA (Industry Standard Architecture) bus, a PCI (Peripheral Component Interconnect) bus, or an EISA (Extended Industry Standard Architecture) bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. For the sake of representation, Figure 13 only a bidirectional arrow is used in the figure, but it does not mean that there is only one bus or one type of bus.

[0112] The memory is used to store programs. Specifically, the program may include program code, and the program code includes computer operation instructions. The memory can include a memory and a non-volatile memory, and provide instructions and data to the processor.

[0113] The processor reads the corresponding computer program from the non-volatile memory into the memory and then runs it, forming a vascular imaging device at the logical level. The processor executes the program stored in the memory and is specifically used to perform the following operations:

[0114] Obtain a plurality of echo images of the region of interest. Among them, the plurality of echo images at least include a first echo image and a second echo image. Among them, both the first echo image and the second echo image include vascular signals and background signals. The vascular signal intensity of the first echo image is greater than the vascular signal intensity of the second echo image, and the background signal intensity of the first echo image is greater than the background signal intensity of the second echo image;

[0115] Perform region of interest fusion on the vascular signal of the first echo image and the background signal of the second echo image to obtain the target vascular image of the region of interest.

[0116] The above as in this application Figure 12The method performed by the vascular imaging device disclosed in the illustrated embodiment can be applied to a processor or implemented by a processor. The processor may be an integrated circuit chip with signal processing capabilities. During implementation, the steps of the above method can be completed by the integrated logic circuit in the hardware of the processor or instructions in software form. The above-mentioned processor may be a general-purpose processor, including a Central Processing Unit (CPU), a Network Processor (NP), etc.; it may also be a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field-Programmable Gate Array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components. It can implement or execute the various methods, steps, and logic block diagrams disclosed in the embodiments of the present application. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc. The steps of the method disclosed in combination with the embodiments of the present application can be directly embodied as being executed and completed by a hardware decoding processor, or executed and completed by a combination of the hardware and software modules in the decoding processor. The software module may be located in a mature storage medium in the art such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory, or an electrically erasable programmable memory, a register, etc. This storage medium is located in the memory, and the processor reads the information in the memory and combines its hardware to complete the steps of the above method.

[0117] The electronic device can also execute Figure 12 the method performed by the vascular imaging device in Figure 12 the illustrated embodiment and implement the functions of the vascular imaging device in

[0118] Embodiments of the present application also propose a computer-readable storage medium that stores one or more programs. The one or more programs include instructions that, when executed by an electronic device including multiple application programs, can enable the electronic device to execute Figure 12 the method performed by the vascular imaging device in the illustrated embodiment, and specifically used to execute:

[0119] Obtain multiple echo images of the region of interest, where the multiple echo images at least include a first echo image and a second echo image. Among them, both the first echo image and the second echo image include vascular signals and background signals. The vascular signal intensity of the first echo image is greater than that of the second echo image, and the background signal intensity of the first echo image is the background signal intensity of the second echo image;

[0120] Perform region of interest fusion on the vascular signal of the first echo image and the background signal of the second echo image to obtain the target vascular image of the region of interest.

[0121] Those skilled in the art should understand that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0122] The present application is described with reference to the flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or block in the flowchart and / or block diagram can be implemented by computer program instructions, and the combination of the processes and / or blocks in the flowchart and / or block diagram can also be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate a machine for implementing the functions specified in one process Figure 1 One process or multiple processes and / or blocks Figure 1 A device for the functions specified in one block or multiple blocks.

[0123] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory generate a manufactured article including an instruction device, and the instruction device implements the functions specified in one process Figure 1 One process or multiple processes and / or blocks Figure 1 A device for the functions specified in one block or multiple blocks.

[0124] These computer program instructions can also be loaded onto a computer or other programmable data processing device, so that a series of operation steps are executed on the computer or other programmable device to generate a computer-implemented process. Therefore, the instructions executed on the computer or other programmable device provide for implementing the functions in the process Figure 1A process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0125] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0126] The memory may include non-permanent storage in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. The memory is an example of a computer-readable medium.

[0127] Computer readable media include permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. Information can be computer readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer readable media does not include temporary computer readable media (transitory media), such as modulated data signals and carrier waves.

[0128] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0129] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0130] The above are only embodiments of the present application and are not intended to limit the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the scope of the claims of the present application.

Claims

1. A method for vascular imaging, characterized in that, the method includes: acquiring a plurality of echo images of an area of interest, wherein the plurality of echo images at least include a first echo image and a second echo image, wherein both the first echo image and the second echo image include vascular signals and background signals, the vascular signal intensity of the first echo image is greater than that of the second echo image, and the background signal intensity of the first echo image is greater than that of the second echo image; performing region of interest fusion on the vascular signal of the first echo image and the background signal of the second echo image to obtain a target vascular image of the area of interest; The performing region of interest fusion on the first echo image and the second echo image to obtain a target vascular image of the area of interest includes: extracting a foreground sequence from the first echo image according to the plurality of echo images, the foreground sequence includes the vascular signal of the first echo image, and in the foreground sequence, the pixel points corresponding to the vascular signal in the first echo image are non-zero pixel points; fusing the foreground sequence with the second echo image to obtain a target vascular image of the area of interest.

2. The method according to claim 1, characterized in that, the first echo image is the echo image with the shortest echo time within a repetition time unit during nuclear magnetic resonance imaging based on the time-of-flight method; the second echo image is the echo image with water-fat phase inversion within the one repetition time unit.

3. The method according to claim 1, characterized in that, the extracting a foreground sequence from the first echo image according to the plurality of echo images includes: determining a first mask of the target blood vessel according to the intensity of each pixel point of the second echo image; extracting the pixel points corresponding to the vascular signal in the first echo image according to the first mask to obtain the foreground sequence.

4. The method according to claim 3, characterized in that, the determining a first mask of the target blood vessel according to the intensity of each pixel point of the second echo image includes: acquiring the maximum value of the intensity of each pixel point of the second echo image; setting an intensity threshold according to the maximum value; if the intensity of a pixel point in the second echo image is greater than the intensity threshold, then taking this pixel point as a non-zero pixel point of the first mask; determining the first mask according to the determined plurality of non-zero pixel points.

5. The method according to claim 4, characterized in that, the determining a first mask of the target blood vessel according to the intensity of each pixel point of the second echo image further includes: performing multi-layer convolution processing on the first mask with a specified matrix, wherein the specified matrix is a matrix of all 1s, and the size of the specified matrix is determined according to the size of the first mask; determining the union of the masks obtained in each layer of the multi-layer convolution and taking the union as the first mask of the target blood vessel.

6. The method according to claim 1, characterized in that, the fusing the foreground sequence with the second echo image to obtain a target vascular image of the area of interest includes: Assign the non-zero pixel points in the foreground sequence to the corresponding positions in the second echo image; Use the second echo image after assignment as the target blood vessel image.

7. A blood vessel imaging method, characterized in that, the method includes: Obtain multiple echo images of the region of interest, where the multiple echo images at least include a first echo image and a second echo image. The first echo image and the second echo image both include blood vessel signals and background signals. The blood vessel signal intensity of the first echo image is greater than that of the second echo image, and the background signal intensity of the first echo image is greater than that of the second echo image; Perform region of interest fusion on the blood vessel signal of the first echo image and the background signal of the second echo image to obtain the target blood vessel image of the region of interest; The multiple echo images further include a third echo image, the third echo image includes blood vessel signals and background signals, and the background signal of the third echo image is greater than the background signal intensity of the second echo image; The performing region of interest fusion on the first echo image and the second echo image to obtain the target blood vessel image includes: According to the intensity difference of each pixel point in the second echo image and the third echo image, extract the background sequence from the second echo image. The background sequence includes the background signal of the second echo image. In the background sequence, the pixel points at the corresponding positions of the background signal of the second echo image are non-zero pixel points; Fuse the background sequence with the first echo image to obtain the target blood vessel image.

8. The method according to claim 7, characterized in that, The third echo image is an echo image with the same water-fat phase within the same repetition time unit as the first echo image and the second echo image.

9. The method according to claim 7, characterized in that, The extracting the background sequence from the second echo image according to the intensity difference of each pixel point in the second echo image and the third echo image includes: Determine the second mask of the fat background according to the intensity difference of each pixel point in the second echo image and the third echo image; According to the second mask, extract the pixel points of the background signal in the second echo image to obtain the background sequence.

10. The method according to claim 7, characterized in that, The fusing the background sequence with the first echo image to obtain the target blood vessel image includes: Assign the non-zero pixel points in the background sequence to the corresponding positions in the first echo image; Use the first echo image after assignment as the target blood vessel image.

11. The method according to any one of claims 1 to 10, characterized in that, the method further includes: Perform e-exponential transformation on the obtained target blood vessel image based on the following formula to obtain the target blood vessel optimized image: image new = (1 - (a * image + e -image )) b ; Among them, image new is the optimized image of the target blood vessel, the image is the target blood vessel image, a = 0.4, b = 2.

12. A blood vessel imaging device, characterized in that, the device includes: An acquisition unit, configured to acquire a plurality of echo images of a region of interest, where the plurality of echo images at least include a first echo image and a second echo image, and both the first echo image and the second echo image include vascular signals and background signals, the vascular signal intensity of the first echo image is greater than that of the second echo image, and the background signal intensity of the first echo image is greater than that of the second echo image; A fusion unit, configured to perform region of interest fusion on the vascular signal of the first echo image and the background signal of the second echo image to obtain a target vascular image of the region of interest; The fusion unit is configured to extract a foreground sequence from the first echo image according to the plurality of echo images, the foreground sequence includes the vascular signal of the first echo image, and in the foreground sequence, the pixel points corresponding to the vascular signal in the first echo image are non-zero pixel points; and fuse the foreground sequence with the second echo image to obtain a target vascular image of the region of interest.

13. An electronic device comprising: A processor; And a memory arranged to store computer-executable instructions, which when executed cause the processor to execute the method according to any one of claims 1 to 11.

14. A computer-readable storage medium storing one or more programs, which when executed by an electronic device including a plurality of application programs, cause the electronic device to execute the method according to any one of claims 1 to 11.

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