Device and method for monitoring bulge type dialysis internal fistula

Abstract

The invention discloses a method and a device for monitoring bulging internal arteriovenous fistula. The monitoring method comprises the following steps: acquiring an arm image of a patient with internal arteriovenous fistula; extracting a bump area of the arm image; bulge density lines of the bulge area are drawn, the trend of the bulge density lines is drawn in the flowing direction of arteries and veins, and the density of the bulge density lines is arranged along the width of the bulge area; selecting at least two points of interest of the bump density line; collecting blood flow impact noise of the point of interest through a sensing device; and analyzing the internal fistula state of the bulge area according to the blood flow impact noise of the at least two points of interest. According to the internal arteriovenous fistula bulge monitoring system and method, the blood flow impact noise of the bulge area of the internal arteriovenous fistula is read through the sensing device so as to analyze the blood flow impact noise of a plurality of different point positions in the bulge area, and monitoring of the internal arteriovenous fistula bulge is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of nephropathy dialysis, and particularly to a monitoring device and method for a bulging dialysis arteriovenous fistula. Background Art

[0002] An arteriovenous fistula is the most commonly used vascular access for maintenance hemodialysis patients and is the lifeline of the patients. It requires patients and medical staff to regularly monitor its function to maintain the long-term patency of the fistula, reduce the occurrence of complications, relieve the pain and economic burden of the patients, and improve the quality of life of the patients.

[0003] Most patients will form an arteriovenous fistula bulge during long-term hemodialysis. There are various possibilities for the formation of an arteriovenous fistula bulge, such as hemodynamic changes, vascular injury, infection, etc. The arteriovenous fistula bulge will directly affect the intensity, range, and nature of the fistula murmur by changing the blood flow velocity, direction, and vascular structure, and have an impact on the monitoring of the arteriovenous fistula. Summary of the Invention

[0004] In view of this, a first aspect of the present invention discloses a monitoring method for a bulging arteriovenous fistula.

[0005] The monitoring method includes the following steps:

[0006] Obtain an arm image of a patient with an arteriovenous fistula;

[0007] Extract the bulging area of the arm image;

[0008] Draw a bulging density line of the bulging area, wherein the direction of the bulging density line is drawn along the blood flow direction of the arteriovenous, and the density of the bulging density line is arranged along the width of the bulging area;

[0009] Select at least two points of interest on the bulging density line;

[0010] Collect the blood flow impact murmur of the points of interest through a sensing device;

[0011] Analyze the fistula state of the bulging area according to the blood flow impact murmurs of at least two of the points of interest.

[0012] In some embodiments disclosed by the present invention,

[0013] The arm image includes at least two discontinuous bulging areas.

[0014] In some embodiments disclosed by the present invention,

[0015] Extracting the bulging area includes:

[0016] Obtain the grayscale image of the arm image;

[0017] Extract the gray - scale edges of the gray - scale image using an edge - detection algorithm, and the bulging area is the closed gray - scale edges formed.

[0018] In some embodiments disclosed by the present invention,

[0019] Obtaining the gray - scale edges includes,

[0020] Extract the gray - scale edges of the gray - scale image using an edge - detection algorithm;

[0021] The edge - detection algorithm is the Prewitt edge - detection algorithm, the Sobel edge - detection algorithm, the Laplacian edge - detection algorithm, or an edge - detection algorithm.

[0022] In some embodiments disclosed by the present invention,

[0023] Drawing the density lines of the bulges includes,

[0024] Arrange a number of vector lines along the flow direction of the artery and vein within the bulging area;

[0025] Make a number of the vector lines evenly spaced along the width of the flattened image to form the density lines of the bulges.

[0026] In some embodiments disclosed by the present invention,

[0027] Drawing the density lines of the bulges includes,

[0028] Extract the flattened area of the bulging area;

[0029] Arrange a number of the vector lines along the flow direction of the artery and vein within the flattened area.

[0030] In some embodiments disclosed by the present invention,

[0031] Selecting the points of interest includes,

[0032] Select the starting point, the ending point, and at least one intermediate point of the density lines of the bulges as the points of interest.

[0033] In some embodiments disclosed by the present invention,

[0034] Selecting at least one of the intermediate points includes,

[0035] Divide the density lines of the bulges into several sections along the flow direction of the artery and vein;

[0036] Select the intermediate points in the sections where the density lines of the bulges are dense.

[0037] In some embodiments disclosed by the present invention,

[0038] Monitoring the internal fistula state of the bulging area includes,

[0039] Obtain the blood flow impact murmur of each of the said points of interest;

[0040] Obtain the time domain characteristics and / or frequency domain characteristics of each of the said blood flow impact murmurs;

[0041] Monitor the internal fistula state of the bulging area according to the said time domain characteristics and / or the said frequency domain characteristics.

[0042] Moreover, a second aspect of the present invention discloses a monitoring device for a bulging arteriovenous internal fistula.

[0043] The said monitoring device includes,

[0044] An extraction module, configured to obtain an arm image of a patient with an arteriovenous internal fistula and extract the bulging area of the said arm image;

[0045] A drawing module, configured to draw the bulging density lines of the said bulging area, wherein the direction of the said bulging density lines is drawn along the blood flow direction of the arteriovenous, and the density of the said bulging density lines is arranged along the width of the bulging area;

[0046] A selection module, configured to select at least two points of interest on the said bulging density lines;

[0047] An analysis module, configured to analyze the internal fistula state of the said bulging area according to the blood flow impact murmurs of at least two of the said points of interest.

[0048] The present invention uses a sensing device to read the blood flow impact murmur of the bulging area of the arteriovenous internal fistula, and through the analysis of the blood flow impact murmurs at multiple different points in the bulging area, realizes the discrimination and abnormal monitoring of the bulging of the arteriovenous internal fistula, without the need for ultrasonic images, and realizes simple and convenient monitoring of the bulging of the arteriovenous internal fistula. Description of the Drawings

[0049] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0050] Figure 1 It is a schematic flow chart of the monitoring method for the bulging arteriovenous internal fistula in this embodiment.

[0051] Figure 2 It is a schematic flow chart of obtaining the bulging area in this embodiment.

[0052] Figure 3 It is a schematic flow chart of drawing the bulging density lines in this embodiment.

[0053] Figure 4 This is a schematic flow chart for monitoring the bulging area in this embodiment.

[0054] Figure 5 This is a schematic structural diagram of the monitoring device for the bulging arteriovenous fistula in this embodiment. Specific implementation manners

[0055] Next, in combination with the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0056] This embodiment discloses a monitoring method for a bulging arteriovenous fistula. The monitoring method is used to monitor the state of the arteriovenous fistula in the bulging area when a bulging arteriovenous fistula appears in the arm of a dialysis patient.

[0057] Among them, the bulging arteriovenous fistula refers to one or more bulges formed at the position of the arteriovenous fistula in the patient's arm. The possible reasons for the formation of the bulges in the arteriovenous fistula are as follows:

[0058] Physiological dilation: After the arteriovenous fistula is established, arterial blood directly flows into the vein, and the vein gradually dilates and thickens due to the high-pressure blood flow. Appropriate physiological dilation is a normal phenomenon for the blood vessels to adapt to the arteriovenous fistula, but excessive physiological dilation may cause bulges in the arteriovenous fistula;

[0059] True aneurysm: The entire layer of the blood vessel wall gradually bulges under the long-term impact of high-pressure blood flow, forming a spindle-shaped or sac-like dilation;

[0060] False aneurysm: Due to puncture injury or infection, the blood vessel wall ruptures, and the extravasated blood is wrapped by the surrounding tissues to form a hematoma, which forms a tumor-like structure communicating with the blood vessel lumen after organization, causing a bulge at the position where the arteriovenous fistula is located;

[0061] Weak blood vessel wall: Long-term puncture at the same position will cause fibrosis of the blood vessel wall, weakened elasticity, and local bulging is likely to occur under the impact of blood flow, causing a bulge at the position where the arteriovenous fistula is located.

[0062] Then, different formation reasons of the bulges in the arteriovenous fistula will cause different blood flow channel structures to be formed in the blood vessel wall and its surrounding tissues. Different blood flow channel structures have a direct impact on the monitoring of the bulges and abnormalities of the arteriovenous fistula. In the prior art, the monitoring of the bulging arteriovenous fistula mainly relies on ultrasonic examination in a medical institution, which is not conducive to the dialysis patient to frequently and independently monitor the bulges of the arteriovenous fistula.

[0063] In this embodiment, the monitoring method uses a sensing device (such as a smart stethoscope) to read the blood flow impact murmur in the bulging area of the arteriovenous fistula, and through the analysis of the blood flow impact murmurs at multiple different points in the bulging area, the discrimination of the bulging of the arteriovenous fistula and its abnormal monitoring are realized.

[0064] Figure 1 It is a monitoring method for a bulging arteriovenous fistula.

[0065] Figure 1 It is shown that the monitoring method includes the following steps 10 to step 60.

[0066] 10 Obtain an arm image of a dialysis patient with an arteriovenous fistula.

[0067] Among them, the arm image with an arteriovenous fistula means that the dialysis patient uses an electronic device with a shooting function (such as a mobile phone terminal) to take a photo of their own arm. The arm image shows the arteriovenous fistula of the dialysis patient at the wrist of the arm, and obvious bulges are formed on the arteriovenous fistula and its surrounding areas with respect to the skin surface. The bulges may be frustum-shaped or may be in a state of blood vessel dilation, etc. There may be multiple discontinuous bulges on the arms of some dialysis patients. For example, multiple bulges are formed due to multiple punctures at multiple places of the arteriovenous fistula. In this embodiment, a dermoscope or a high-resolution camera can be used to take the arm image to ensure uniform light without shadow interference.

[0068] Moreover, after taking the arm image in step 10, the arm image can be subjected to denoising processing and contrast enhancement processing.

[0069] For the denoising processing of the arm image, Gaussian filtering can be applied to eliminate the texture noise on the patient's skin and retain the contour of the bulging area.

[0070] For the contrast enhancement processing of the arm image, the histogram equalization can be used to highlight the brightness and darkness difference between the bulging area and the surrounding skin, which is beneficial to the edge detection of the bulging area in the subsequent steps.

[0071] 20 Extract the bulging area of the arm image.

[0072] Among them, the bulging area has a physiological structure that is significantly prominent from the general arm skin. The number of bulging areas on the arms of most patients is 1, and for a small number of patients, due to the need for repeated multi-point punctures during long-term dialysis, the number of bulging areas on the arm may be greater than 1.

[0073] Figure 2 It is a schematic flow chart for obtaining the bulging area.

[0074] Figure 2 It is shown that obtaining the bulging area includes the following steps.

[0075] 21 Extract the bulging area in the arm image.

[0076] Among them, in this embodiment, after converting the RGB arm image into a grayscale image, a grayscale threshold (such as 120 - 200) is set to segment the highlighted area, and then morphological closing operation is combined to remove noise. The grayscale threshold is set according to the skin color of different dialysis patients. Optionally, before taking the arm image, colored iodine tincture can be applied to the arteriovenous fistula and its surrounding area of the dialysis patient's arm in advance. The colored iodine tincture helps to segment the highlighted area and can be used for skin surface disinfection.

[0077] 22 Obtain the grayscale edge of the grayscale image through the edge detection algorithm, and the bulging area forms a closed grayscale edge.

[0078] Among them, in this embodiment, an edge detection operator (Canny operator) or Sobel edge detection algorithm (Sobel operator) is used to initially extract the contour edge of the bulging area, and then the Hough transform is used to identify the closed contour as the area boundary of the bulging area.

[0079] In some embodiments, the Prewitt operator or Laplace operator can also be selected to enhance the edge contrast of the bulging area.

[0080] 30 Draw the density lines of the bulging area.

[0081] Among them, the direction of the density lines of the bulging area is drawn along the blood flow direction of the arteriovenous (from the proximal end to the distal end). The density of the density lines of the bulging area is adjusted according to the width of the bulging area. For example, a dense line (interval 1mm) is set at the widest part of the bulge, and the edge area is sparse (interval 5mm), and the density lines are superimposed on the bulging area in the form of vector line segments.

[0082] Specifically, Figure 3 is a schematic flow diagram for drawing the density lines of the bulging area.

[0083] Figure 3 It shows that drawing the density lines of the bulging area includes the following steps.

[0084] 31 Extract the flattened area of the bulging area.

[0085] Among them, the flattened area refers to performing a perspective transformation on the bulging area and then generating a two-dimensional flattened image to eliminate surface distortion.

[0086] 32 Arrange a number of vector lines along the blood flow direction of the arteriovenous in the bulging area.

[0087] 33 Make the number of vector lines evenly spaced following the width of the flattened image to form the density lines of the bulging area.

[0088] 34 Arrange a number of vector lines along the blood flow direction of the arteriovenous in the flattened area.

[0089] Among them, parallel vector lines are generated at equal intervals (such as every 5 pixels) along the blood flow direction in the flattened image, and the bulge density is adaptively adjusted according to the bulge width. There may be a gradual change area between the edge of the bulge of the patient and the normal skin. The line density in the gradual change area can gradually decrease from high to low, and the direction is radially arranged along the skin texture.

[0090] In some embodiments, the bulge density lines serve the function of providing diagnostic observation for medical staff. Therefore, when drawing the bulge density lines, the bulge area and a certain range of the surrounding skin can be covered at the same time. At this time, the top of the bulge can be regarded as the top layer, the transition from the bulge to the surrounding skin can be regarded as the transition layer, and the surrounding skin can be regarded as the flat layer. The top layer includes the highest position of the bulge, and the bulge density lines are the densest; the transition layer includes the gradual change area from the bulge edge to the normal skin, and the bulge density lines show a decreasing change; the flat layer includes the surrounding healthy skin, and the bulge density lines are the sparsest.

[0091] Then, in this embodiment, the degree of bulge relative to the skin protrusion can be automatically reflected by the bulge density in terms of the degree of density.

[0092] 40 Select several points of interest on the bulge density lines.

[0093] Among them, the bulge density lines are divided into 3 sections (proximal, middle, and distal) according to the blood flow direction, and 2 points of interest are set at the proximal starting point and the distal end point. 2 points of interest are set in the middle dense area (interval greater than 1 cm).

[0094] 50 Collect the blood flow impact murmur at the points of interest through a sensing device.

[0095] Among them, an electronic stethoscope or a portable ultrasonic Doppler device can be selected as the sensing device.

[0096] An electronic stethoscope is a medical device that combines the functions of a traditional stethoscope and modern electronic technology. Through electronic amplification, noise reduction, and digital processing, the audio and vibration signals obtained by auscultation are significantly improved. A portable ultrasonic Doppler device is an instrument that uses the ultrasonic Doppler effect for measurement, such as a portable Doppler flowmeter. It uses the ultrasonic Doppler effect to calculate the flow velocity by measuring the change in the frequency of the reflected wave of substances in the fluid. In some embodiments, an electrode can be selected as the sensing device, that is, the vibration of an object is detected by the voltage difference between the two plates of a capacitor. When the object vibrates, the distance between the plates of the capacitor changes, resulting in a change in the capacitance value, thereby generating a voltage difference, and then the vibration is detected.

[0097] The blood flow impact murmur is a physical manifestation of high-speed and turbulent blood flow impacting the blood vessel wall, which is closely related to the hemodynamic changes in arteriovenous fistulas. The characteristics of the blood flow impact murmur (such as phase, intensity, nature) can reflect the patency, blood flow status, and potential complications of the fistula and the bulge.

[0098] When the sensing device collects the blood flow impact murmur, the blood flow impact murmur collected by the sensing device at different points of interest may be different. The reason is that there may be differences in the internal structures of the blood vessel walls and their surrounding tissues corresponding to different points of interest in the bulging area.

[0099] Analyze the internal fistula state of the bulging area based on the blood flow impact murmurs at at least two points of interest.

[0100] Among them, Figure 4 is a schematic flow chart for monitoring the bulging area.

[0101] Figure 4 Showing that monitoring the internal fistula state of the bulging area includes the following steps.

[0102] 61 Obtain the blood flow impact murmurs at each point of interest.

[0103] 62 Obtain the time-domain characteristics and frequency-domain characteristics of each blood flow impact murmur.

[0104] Among them, obtaining the time-domain characteristics means extracting the peak intensity, vibration period, etc. of the blood flow impact murmur to obtain several time-domain characteristics.

[0105] For example, the mean absolute value reflects the average intensity of the signal during this period. The greater the intensity of the blood flow impact murmur, the greater this value. This feature is the estimated mean absolute value of the signal x within the analysis window of N samples and is defined as follows:

[0106]

[0107] In the formula, X k represents the kth sample value within the analysis window.

[0108] Another example is the variance, which is the degree of deviation between the collected blood flow impact murmur and its corresponding average value. This feature reflects the variation range of the blood flow impact murmur, and its calculation formula is as follows:

[0109]

[0110] In the above formula, N refers to the number of collections of the measured blood flow impact murmur, X k refers to the vibration amplitude at the kth sampling point position in the selected blood flow impact murmur, refers to the average value corresponding to the blood flow impact murmur.

[0111] Among them, obtaining the frequency-domain characteristics means performing a short-time Fourier transform (STFT) on the signal of the blood flow impact murmur to extract several frequency-domain characteristics (such as the main frequency peak position, energy distribution, etc.).

[0112] For example, Short-Time Fourier Transform (STFT), Spectral Centroid, Band Energy Ratio, Mel Frequency Cepstral Coefficient (MFCC), Harmonic-to-Noise Ratio (HNR).

[0113] 63 Monitor the arteriovenous fistula status in the bulging area according to time-domain features and frequency-domain features.

[0114] For example, if the main frequency difference between two points of interest at the adjacent proximal starting point and distal ending point > 20% and there is a lag exceeding a certain delay, it is determined that the arteriovenous fistula has a stenosis risk and the middle section of the bulging area has an impact on the stenosis risk.

[0115] Again, calculate the Root Mean Square (RMS) value of the murmur signal. If the RMS difference between adjacent points > 15 dB, it indicates abnormal blood flow.

[0116] Alternatively, extract the energy proportion of the 200 - 800 Hz frequency band for the points of interest. If the proportion of each point of interest < 30%, it is determined that the arteriovenous fistula function has degenerated; if the proportion of the proximal starting point is greater than 80%, it is determined that the arteriovenous fistula function degeneration is caused by the removal of the bulging area.

[0117] Furthermore, Figure 5 This embodiment discloses a monitoring device for a bulging arteriovenous fistula.

[0118] Figure 5 This embodiment shows that the monitoring device includes an extraction module, a drawing module, a selection module, and an analysis module.

[0119] Among them, the extraction module is used to obtain the arm image of the patient with an arteriovenous fistula and extract the bulging area of the arm image;

[0120] Among them, the drawing module is used to draw the bulging density line of the bulging area. The trend of the bulging density line is drawn along the blood flow direction of the arteriovenous, and the density of the bulging density line is arranged along the width of the bulging area;

[0121] Among them, the selection module is used to select at least two points of interest on the bulging density line;

[0122] Among them, the analysis module is used to analyze the arteriovenous fistula status in the bulging area according to the blood flow impact murmur of at least two points of interest.

[0123] This embodiment discloses a schematic structural diagram of an electronic device. This application provides an electronic device, including: a processor and a memory. The processor and the memory are interconnected and communicate with each other through a communication bus and / or other forms of connection mechanisms (not marked). The memory stores a computer program executable by the processor. When the computing device runs, the processor executes the computer program to perform the method in any optional implementation manner of the above-described embodiment when executed.

[0124] This embodiment discloses a storage medium, on which a computer program is stored. When the computer program is executed by a processor, it performs the method in any optional implementation manner of the above-described embodiment. Among them, the storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (Static Random Access Memory, abbreviated as SRAM), electrically erasable programmable read-only memory (Electrically Erasable Programmable Read-Only Memory, abbreviated as EEPROM), erasable programmable read-only memory (Erasable Programmable Read Only Memory, abbreviated as EPROM), programmable read-only memory (Programmable Red-Only Memory, abbreviated as PROM), read-only memory (Read-Only Memory, abbreviated as ROM), magnetic memory, flash memory, a magnetic disk or an optical disc.

[0125] From the above description of the embodiments, those skilled in the art can clearly understand that the present invention can be implemented by means of software and necessary general-purpose hardware. Of course, it can also be implemented by hardware, but in many cases the former is a better implementation manner.

[0126] Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as a floppy disk, read-only memory (Read-Only Memory, ROM), random access memory (Random Access Memory, RAM), flash memory (FLASH), a hard disk or an optical disc of a computer, etc. It includes several instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to perform the methods of various embodiments of the present invention.

[0127] Note that the above is only the preferred embodiment of the present invention and the technical principles applied. Those skilled in the art will understand that the present invention is not limited to the specific embodiments here, and various obvious changes, re-adjustments and substitutions can be made by those skilled in the art without departing from the protection scope of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments. Without departing from the concept of the present invention, more other equivalent embodiments can be included, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A monitoring method for a bulging arteriovenous fistula, characterized in that, the monitoring method includes the following steps, acquiring an arm image of a patient with an arteriovenous fistula; extracting the bulging area of the arm image; drawing a bulging density line of the bulging area, wherein the direction of the bulging density line is drawn along the flow direction of the arteriovenous, and the density of the bulging density line is arranged along the width of the bulging area; selecting at least two points of interest on the bulging density line; collecting the blood flow impact murmur of the points of interest through a sensing device; analyzing the fistula state of the bulging area according to the blood flow impact murmur of at least two of the points of interest.

2. The monitoring method for a bulging arteriovenous fistula according to claim 1, characterized in that, the arm image includes at least two discontinuous bulging areas.

3. The monitoring method for a bulging arteriovenous fistula according to claim 1, characterized in that, extracting the bulging area includes, acquiring a grayscale image of the arm image; using an edge detection algorithm to extract the grayscale edge of the grayscale image, and the bulging area is the closed grayscale edge formed.

4. The monitoring method for a bulging arteriovenous fistula according to claim 3, characterized in that, acquiring the grayscale edge includes, using an edge detection algorithm to extract the grayscale edge of the grayscale image; the edge detection algorithm is a Prewitt edge detection algorithm, a Sobel edge detection algorithm, a Laplace edge detection algorithm or a Canny edge detection algorithm.

5. The monitoring method for a bulging arteriovenous fistula according to claim 1, characterized in that, drawing the bulging density line includes, configuring a number of vector lines along the flow direction of the arteriovenous in the bulging area; making the number of vector lines evenly spaced along the width of the flattened image to form the bulging density line.

6. The monitoring method for a bulging arteriovenous fistula according to claim 5, characterized in that, drawing the bulging density line includes, extracting the flattened area of the bulging area; configuring a number of the vector lines along the flow direction of the arteriovenous in the flattened area.

7. The monitoring method for a bulging arteriovenous fistula according to claim 1, characterized in that, selecting the points of interest includes, selecting the starting point, the ending point and at least one intermediate point of the bulging density line as the points of interest.

8. The monitoring method for a bulging arteriovenous fistula according to claim 7, characterized in that, selecting at least one of the intermediate points includes, dividing the bulging density line into several sections along the flow direction of the arteriovenous; selecting the intermediate point in the section where the bulging density line is dense.

9. The monitoring method for a bulging arteriovenous fistula according to claim 1, characterized in that, monitoring the fistula state of the bulging area includes, acquiring the blood flow impact murmur of each of the points of interest; acquiring the time-domain feature and / or frequency-domain feature of each of the blood flow impact murmurs; monitoring the fistula state of the bulging area according to the time-domain feature and / or the frequency-domain feature.

10. A monitoring device for a bulging arteriovenous fistula, characterized in that, the monitoring device includes, An extraction module, configured to obtain an arm image of a patient with an arteriovenous fistula and extract the bulging area of the arm image; A drawing module, configured to draw the bulging density lines of the bulging area, wherein the trend of the bulging density lines is drawn along the blood flow direction of the arteriovenous fistula, and the density of the bulging density lines is arranged along the width of the bulging area; A selection module, configured to select at least two points of interest on the bulging density lines; An analysis module, configured to analyze the fistula state of the bulging area according to the blood flow impact murmurs of at least two of the points of interest.

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