Hemodialysis patient autologous internal arteriovenous fistula monitoring system and method

Abstract

The invention provides a system and a method for monitoring autologous internal arteriovenous fistula of a hemodialysis patient, and relates to the technical field of blood monitoring. Vein data, fat data and muscle data of the patient in the measuring process are collected by analyzing the Doppler ultrasonic blood flow measuring process, and the autologous internal arteriovenous fistula of the patient is obtained by analyzing a vein three-dimensional model; acquiring a vein inner wall area deviation index for reflecting the deviation degree of the vein area of the patient measured by the color Doppler ultrasonic wave, and performing correlation analysis on the fat data and the muscle data; and generating a flow velocity deviation index for reflecting the blood flow measurement deviation degree caused by muscle and fat thickness in the Doppler ultrasonic blood flow velocity measurement process, comprehensively analyzing the flow velocity deviation index and the flow velocity deviation index to generate a blood flow deviation index, comparing the blood flow deviation index with a threshold value, and outputting the blood volume monitoring accuracy level.

Description

Technical Field

[0001] The present invention relates to the technical field of blood monitoring, and particularly to a monitoring system and method for the autogenous arteriovenous fistula of hemodialysis patients. Background Technique

[0002] An autogenous arteriovenous fistula is a common vascular surgery mainly used for hemodialysis of patients with chronic renal failure. This surgery creates an abnormal blood flow channel by directly connecting a vein to an artery, allowing arterial blood flow to enter the vein, thereby increasing the blood flow and inner diameter of the vein for subsequent dialysis. The advantages of an autogenous arteriovenous fistula include a lower infection risk, fewer complications, and a longer service life, and it can ensure the effectiveness of dialysis better than artificial blood vessels. The surgery is usually performed on the forearm or upper arm and requires a certain healing time after the operation for the fistula to mature and provide an appropriate blood flow. A mature fistula can provide a stable and repeatable dialysis access, ensuring that the patient receives sufficient blood flow during dialysis to meet the need for removing toxins and excess water from the body.

[0003] Before the operation, it is necessary to monitor the patient's blood. The operation can be performed only when the blood flow meets the surgical standard. When monitoring the autogenous arteriovenous fistula of hemodialysis patients, the blood flow of the patient is monitored. During the monitoring process, the Doppler ultrasound measurement method is often used. This method is calculated based on the conventional sound velocity of human tissues, and only part of the area is calculated when calculating the cross-section of the blood vessel. Due to the different contents of muscle and fat in the human body of different patients, the cross-section of the blood vessel also has differences, so the error of the obtained blood flow result is relatively large.

[0004] The above information disclosed in the background art section is only used to strengthen the understanding of the background of the present disclosure, so it may include information that does not constitute the prior art known to those of ordinary skill in the art. Summary of the Invention

[0005] The purpose of the present invention is to provide a monitoring system and method for the autogenous arteriovenous fistula of hemodialysis patients to solve the problems raised in the above background art.

[0006] To achieve the above purpose, the present invention provides the following technical solutions:

[0007] A monitoring method for the autogenous arteriovenous fistula of hemodialysis patients, the specific steps include:

[0008] S1. Determine the vein of the autogenous arteriovenous fistula to be monitored, and scan the limb where the vein is located by computer tomography to construct a three-dimensional model of the limb;

[0009] S2. Conduct a correlation analysis on the three-dimensional model of the limb to generate a three-dimensional venous model, a three-dimensional fat model, and a three-dimensional muscle model. Among them, the three-dimensional venous model is used to reflect the three-dimensional model of the limb veins, the three-dimensional fat model is used to reflect the three-dimensional model of the limb fat, and the three-dimensional muscle model is used to reflect the three-dimensional model of the limb muscles;

[0010] S3. Place the three-dimensional model of the venous part in a coordinate system for correlation analysis to generate venous area parameters, and the venous area parameters include the venous cross-sectional area and the mean area;

[0011] S4. Conduct a correlation analysis on the venous area parameters to generate a venous inner wall area deviation index S, and the venous inner wall area deviation index S is used to reflect the deviation degree of measuring the venous area of the patient through color Doppler ultrasound;

[0012] S5. Reconstruct a three-dimensional coordinate system, place the three-dimensional fat model and the three-dimensional muscle model in the reconstructed three-dimensional coordinate system, where the emission direction of the Doppler ultrasound coincides with the Z-axis, and conduct a correlation analysis on the three-dimensional fat model and the three-dimensional muscle model to generate a fat thickness and a muscle thickness. The fat thickness is the effective fat thickness of the path during the transmission of the Doppler ultrasound, and the muscle thickness is the effective muscle thickness of the path during the transmission of the Doppler ultrasound;

[0013] S6. Conduct a correlation analysis on the fat thickness and the muscle thickness to generate a weighted sound velocity, and conduct a correlation analysis on the weighted sound velocity to generate a flow velocity deviation index. The flow velocity deviation index is used to reflect the degree of blood flow measurement deviation caused by the muscle and fat thicknesses during the measurement of blood flow velocity by Doppler ultrasound;

[0014] S7. Conduct a correlation analysis on the flow velocity deviation index L and the venous inner wall area deviation index S to generate a blood flow deviation index XLP, compare the blood flow deviation index XLP with a threshold ∈, output the accuracy level of the blood flow measurement result based on Doppler ultrasound, and output whether to adopt the blood flow data measured by Doppler ultrasound.

[0015] Further, use the 3DSlicer software to import the data obtained by computer tomography scanning, use the threshold segmentation tool to extract the three-dimensional venous model, and extract the contours of the fat layer and the muscle through the threshold segmentation algorithm to generate the three-dimensional models of the fat and the muscle.

[0016] Further, the limb after autogenous arteriovenous fistula surgery is scanned by a CT scanner, and the collected data is processed by computer software to generate a three-dimensional model of the limb. The three-dimensional model is placed in the XYZ coordinate system, where the line connecting the head and tail endpoints of the vein is parallel to the Z-axis, and the head endpoint of the vein is placed on the XOY plane. N equally spaced cross-sections parallel to the XOY plane are set to truncate and divide the three-dimensional model of the vein, and the intersection line between the three-dimensional model inside the vein and the cross-section is retained. Coordinate points are obtained from the intersection line, and the coordinate points inside the vein on the i-th cross-section are where i is used to index the cross-section, j is used to index the coordinate points obtained on that cross-section, the coordinate points on each cross-section are evenly spaced, and the number of coordinate points on each cross-section is M.

[0017] Further, for the coordinate points inside the vein correlation analysis is performed to generate the venous cross-sectional area S i , and the formula based on is:

[0018]

[0019] where, and are respectively defined as and to form a closed shape. The superscripts j and j + 1 are both used to index the coordinate points on the i-th cross-section. The venous cross-sectional area S i is used to reflect the area of the inner wall of the vein on the i-th cross-section;

[0020] Correlation analysis is performed on the venous cross-sectional area S i to generate the mean area , and the formula based on is:

[0021]

[0022] The mean area is used to reflect the average area of the inner wall of the vein to be monitored for autogenous arteriovenous fistula after segmentation;

[0023] Correlation analysis is performed on the mean area to generate the venous inner wall area deviation index S, and the formula based on is:

[0024]

[0025] where D is the diameter of the blood vessel measured by color Doppler ultrasound, and the venous inner wall area deviation index S is used to reflect the deviation degree of the venous area of the patient measured by color Doppler ultrasound.

[0026] Further, the three-dimensional model of fat is multi-layered. On the Z-axis, the fat layers are numbered, They are the minimum coordinate point and the maximum coordinate point on the Z-axis where the k-th fat layer is located. There are a total of K fat layers. The muscle layers are numbered on the Z-axis. They are the minimum coordinate point and the maximum coordinate point on the Z-axis where the p-th muscle layer is located. There are a total of P muscle layers. A correlation analysis is performed on the three-dimensional fat model and the three-dimensional muscle model to generate the fat thickness Z and the muscle thickness R. The formula is as follows:

[0027]

[0028] α is the scaling ratio of the three-dimensional model to the entity. The fat thickness Z is used to reflect the thickness of the fat along the ultrasonic path during Doppler ultrasound measurement, and the muscle thickness R is used to reflect the thickness of the muscle along the ultrasonic path during Doppler ultrasound measurement.

[0029] Furthermore, a correlation analysis is performed on the fat thickness and the muscle thickness to generate the fat acoustic wave propagation time t Z and the muscle acoustic wave propagation time t R , and the formula is as follows:

[0030]

[0031] Among them, c Z is the propagation speed of sound waves in fat, c R is the propagation speed of sound waves in muscle, which is obtained through laboratory measurement. The fat acoustic wave propagation time t Z is used to reflect the time when sound waves propagate in fat during Doppler ultrasound measurement, and the muscle acoustic wave propagation time t R is used to reflect the time when sound waves propagate in muscle during Doppler ultrasound measurement;

[0032] A correlation analysis is performed on the fat acoustic wave propagation time t Z and the muscle acoustic wave propagation time t R to generate the weighted sound speed c avg , and the formula is as follows:

[0033]

[0034] The weighted sound speed c avg is used to reflect the average sound speed of the Doppler sound speed in the muscle and fat of this patient;

[0035] A correlation analysis is performed on the weighted sound speed c avg to generate the flow velocity deviation index L, and the formula is as follows:

[0036]

[0037] Among them, f dRepresents the Doppler frequency shift, which is used to reflect the difference between the received frequency and the transmitted frequency. f0 is the ultrasonic transmission frequency, θ is the angle between the propagation direction of the ultrasonic wave and the blood flow direction in Doppler ultrasound measurement, 1540 is the value of the sound speed in tissue in conventional Doppler ultrasound measurement, and the flow velocity deviation index L is an index of the deviation degree of blood flow velocity measurement generated based on the muscle and fat thickness of the patient.

[0038] Furthermore, a correlation analysis is performed on the flow velocity deviation index L and the venous inner wall area deviation index S to generate a blood flow deviation index XLP. The formula is as follows:

[0039] XLP = |(1 - S) * L|

[0040] The blood flow deviation index XLP is used to reflect the error deviation degree of blood flow measurement based on Doppler ultrasound at the conventional tissue sound speed. When XLP ≤ ∈, the accuracy level of the blood flow measurement result based on Doppler ultrasound is output as level one, with a small deviation, and the blood flow data measured based on Doppler ultrasound is adopted; when XLP > ∈, the accuracy level of the blood flow measurement result based on Doppler ultrasound is output as level two, with a large deviation, and the blood flow data measured by Doppler ultrasound cannot be used.

[0041] The present invention also provides a monitoring system for the autologous arteriovenous fistula of hemodialysis patients, which is used to execute the monitoring method for the autologous arteriovenous fistula of hemodialysis patients, including:

[0042] A limb model construction module, which is used to determine the vein to be monitored in the autologous arteriovenous fistula, and construct a three-dimensional model of the limb by computer tomography scanning the limb where the vein is located;

[0043] A three-dimensional model analysis module, which is used to perform a correlation analysis on the three-dimensional model of the limb to generate a venous three-dimensional model, a fat three-dimensional model, and a muscle three-dimensional model;

[0044] A vein analysis module, which is used to place the three-dimensional model of the vein part in a coordinate system for correlation analysis to generate vein area parameters, and perform a correlation analysis on the vein area parameters to generate a venous inner wall area deviation index;

[0045] A fat and muscle analysis module, which is used to reconstruct a three-dimensional coordinate system, place the fat three-dimensional model and the muscle three-dimensional model in the reconstructed three-dimensional coordinate system, where the emission direction of the Doppler ultrasonic wave coincides with the Z axis, perform a correlation analysis on the fat three-dimensional model and the muscle three-dimensional model to generate fat thickness and muscle thickness, perform a correlation analysis on the fat thickness and muscle thickness to generate a weighted sound speed, and perform a correlation analysis on the weighted sound speed to generate a flow velocity deviation index;

[0046] A comprehensive analysis module is used to perform a correlation analysis on the flow velocity deviation index L and the venous inner wall area deviation index S to generate a blood flow deviation index XLP, compare the blood flow deviation index XLP with a threshold ∈, output the accuracy level of the blood flow measurement result based on Doppler ultrasound, and output whether to adopt the blood flow data measured by Doppler ultrasound.

[0047] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0048] By analyzing the process of measuring blood flow by Doppler ultrasound, the present invention collects the patient's venous data, fat data, and muscle data during the measurement process. By analyzing the three-dimensional venous model, the venous inner wall area deviation index for reflecting the deviation degree of the venous area measured by color Doppler ultrasound is obtained, and a correlation analysis is performed on the fat data and muscle data to generate a flow velocity deviation index for reflecting the magnitude of the blood flow measurement deviation caused by the thickness of muscle and fat during the process of measuring blood flow by Doppler ultrasound. After comprehensively analyzing the two, a blood flow deviation index is generated and compared with a threshold to output the accuracy level of blood volume monitoring. Description of the Drawings

[0049] Figure 1 It is a schematic diagram of the overall method flow of the present invention;

[0050] Figure 2 It is a schematic diagram of the overall system flow of the present invention. Detailed Embodiments

[0051] To make the objectives, technical solutions, and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with specific embodiments.

[0052] It should be noted that unless otherwise defined, the technical terms or scientific terms used in the present invention should have the ordinary meaning understood by those with ordinary skills in the field to which the present invention belongs. The "first", "second", and similar terms used in the present invention do not indicate any order, quantity, or importance, but are only used to distinguish different components. The terms such as "including" or "comprising" mean that the elements or objects appearing before this term cover the elements or objects listed after this term and their equivalents, without excluding other elements or objects. The terms such as "connected" or "linked" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The terms such as "upper", "lower", "left", "right", etc. are only used to represent relative positional relationships, and when the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0053] Embodiment:

[0054] Please refer to Figure 1 , the present invention provides a technical solution:

[0055] A method for monitoring the autogenous arteriovenous fistula in hemodialysis patients. When monitoring the autogenous arteriovenous fistula in hemodialysis patients, it is necessary to monitor the blood flow of the patient. During the monitoring process, the Doppler ultrasound measurement method is often used. This method is calculated based on the conventional sound velocity of human tissue propagation, and only a partial area is calculated when calculating the cross-sectional area of the blood vessel. Therefore, the error of the obtained blood flow result is relatively large. Among them, the Doppler ultrasound measurement method obtains the partial cross-sectional area A of the blood vessel and obtains the blood flow velocity v, and calculates the blood flow Q through the formula Q = A * v. When obtaining the blood flow velocity v, it is necessary to calculate based on the conventional sound velocity of human tissue, that is, 1540 m / s. However, due to the different contents of muscle and fat in the human body of different patients, the cross-sections of blood vessels also have differences, so the calculation results have differences. In order to evaluate the method for monitoring the autogenous arteriovenous fistula in hemodialysis patients based on Doppler ultrasound measurement, the specific steps include:

[0056] Step 1: Determine the vein of the autogenous arteriovenous fistula to be monitored, and scan the limb where the vein is located by computer tomography to construct a three-dimensional model of the limb;

[0057] Step 2: Conduct a correlation analysis on the three-dimensional model of the limb to generate a three-dimensional vein model, a three-dimensional fat model, and a three-dimensional muscle model. Among them, the three-dimensional vein model is used to reflect the three-dimensional model of the limb vein, the three-dimensional fat model is used to reflect the three-dimensional model of the limb fat, and the three-dimensional muscle model is used to reflect the three-dimensional model of the limb muscle;

[0058] Scan the limb where the vein is located by computer tomography and obtain DICOM data. Use 3DSlicer software to import the DICOM data obtained by computer tomography. Use the threshold segmentation tool to extract the three-dimensional vein model. Extract the contours of the fat layer and muscle through the threshold segmentation algorithm to generate three-dimensional models of fat and muscle. Import the exported three-dimensional models of vein, fat, and muscle into Blender software to create a three-dimensional scene and visually display the three-dimensional models of vein, fat, and muscle.

[0059] Step 3: Place the three-dimensional model of the vein part in a coordinate system for correlation analysis to generate vein area parameters, and the vein area parameters include the cross-sectional area of the vein and the mean area;

[0060] Scan the limb after autogenous arteriovenous fistula surgery with a CT scanner. The collected data is processed by computer software to generate a three-dimensional model of the limb. Place the three-dimensional model in the XYZ coordinate system. For convenience of calculation, align the line connecting the head and tail endpoints of the vein with the Z-axis, and place the head endpoint of the vein on the XOY plane. Set N equally spaced cross-sections parallel to the XOY plane to truncate and divide the three-dimensional model of the vein. Retain the intersection line of the inner contour model of the vein and the cross-section. This intersection line represents the inner wall of the vein. Analyze this intersection line, which is to analyze the inner wall of the vein. Obtain coordinate points from the intersection line. The inner venous coordinate points of the i-th cross-section are where i is used to index the cross-section and j is used to index the coordinate points obtained on that cross-section. To reduce the influence of errors, the coordinate points on each cross-section are evenly spaced, and the number of coordinate points on each cross-section is M.

[0061] For the inner venous coordinate points Perform a correlation analysis to generate the cross-sectional area S of the vein i , and the formula is:[[]]

[0062]

[0063] where and are respectively defined as and to form a closed shape. The superscripts j and j + 1 are both used to index the coordinate points on the i-th cross-section. The cross-sectional area S of the vein i is used to reflect the cross-sectional area of the inner wall of the vein on the i-th cross-section;

[0064] Perform a correlation analysis on the cross-sectional area S of the vein i to generate the mean area , and the formula is:[[]]

[0065]

[0066] The mean area is used to reflect the average area of the inner wall of the vein to be monitored of the autogenous arteriovenous fistula after segmentation, that is, the average cross-sectional area of this section of the inner wall of the vein.

[0067] Step 4: Perform a correlation analysis on the vein area parameters to generate the deviation index S of the inner wall area of the vein. The deviation index S of the inner wall area of the vein is used to reflect the deviation degree of the vein area measured by color Doppler ultrasound for the patient;

[0068] To compare with the cross-sectional area of the blood vessel measured by Doppler ultrasound, perform a correlation analysis on the mean area to generate the deviation index S of the inner wall area of the vein. The formula is:[[]]

[0069]

[0070] Wherein, D is the diameter of the blood vessel measured by color Doppler ultrasound, is the cross-sectional area of the venous blood vessel obtained by Doppler ultrasound measurement. After taking the difference and comparing it with the average area it is possible to obtain the deviation degree of the cross-sectional area of the blood vessel measured by Doppler ultrasound. The venous inner wall area deviation index S is used to reflect the deviation degree of the venous area of the patient measured by color Doppler ultrasound. The larger the value of the venous inner wall area deviation index S, the greater the deviation degree of the cross-sectional area of the blood vessel measured by color Doppler ultrasound.

[0071] Step 5: Reconstruct a three-dimensional coordinate system, place the three-dimensional fat model and the three-dimensional muscle model in the reconstructed three-dimensional coordinate system, wherein the emission direction of the Doppler ultrasound coincides with the Z-axis, perform a correlation analysis on the three-dimensional fat model and the three-dimensional muscle model to generate the fat thickness and the muscle thickness. The fat thickness is the effective fat thickness of the path during the transmission of Doppler ultrasound, and the muscle thickness is the effective muscle thickness of the path during the transmission of Doppler ultrasound;

[0072] The Z-axis is the direction in which the ultrasonic probe emits ultrasonic waves. Both the ultrasonic emission probe and the receiving probe are located on the Z-axis for convenience of calculation. The three-dimensional fat model is multi-layered. On the Z-axis, the fat layers are numbered, are respectively the minimum coordinate point and the maximum coordinate point on the Z-axis where the k-th fat layer is located. There are a total of K fat layers. On the Z-axis, the muscle layers are numbered, are respectively the minimum coordinate point and the maximum coordinate point on the Z-axis where the p-th muscle layer is located. There are a total of P muscle layers. Perform a correlation analysis on the three-dimensional fat model and the three-dimensional muscle model to generate the fat thickness Z and the muscle thickness R. The formula based on is:

[0073]

[0074] α is the scaling ratio between the three-dimensional model and the entity. The fat thickness Z is used to reflect the fat thickness on the ultrasonic path during the measurement by Doppler ultrasound, and the muscle thickness R is used to reflect the muscle thickness on the ultrasonic path during the measurement by Doppler ultrasound. The more the ratio of the muscle thickness to the fat thickness deviates from the standard human body ratio, the less accurate the blood flow velocity obtained by Doppler ultrasound measurement;

[0075] The formula for measuring blood flow velocity by Doppler ultrasound is: f0 is the initial ultrasonic frequency, θ is the angle between the ultrasonic probe and the blood flow direction, and C is the speed of sound. The standard speed of sound in human tissues, i.e., 1540 m / s, is used during calculation.

[0076] Step 6: Conduct a correlation analysis on the fat thickness and muscle thickness to generate a weighted sound velocity. Then, conduct a correlation analysis on the weighted sound velocity to generate a flow velocity deviation index, which is used to reflect the degree of blood flow measurement deviation caused by muscle and fat thickness during the measurement of blood flow velocity by Doppler ultrasound;

[0077] Conduct a correlation analysis on the fat thickness and muscle thickness to generate the fat acoustic wave propagation time t Z and the muscle acoustic wave propagation time t R , and the formula is:

[0078]

[0079] where c Z is the propagation speed of sound waves in fat, and c R is the propagation speed of sound waves in muscle, which is obtained through laboratory measurement. The fat acoustic wave propagation time t Z is used to reflect the time when sound waves propagate in fat during Doppler ultrasound measurement, and the muscle acoustic wave propagation time t R is used to reflect the time when sound waves propagate in muscle during Doppler ultrasound measurement;

[0080] Conduct a correlation analysis on the fat acoustic wave propagation time t Z and the muscle acoustic wave propagation time t R to generate a weighted sound velocity c avg , and the formula is:

[0081]

[0082] The weighted sound velocity c avg is used to reflect the mean sound velocity of Doppler sound velocity in the muscle and fat of this patient. Since the proportion of blood vessels and nerve tissues in the limb is extremely small, they do not participate in the calculation. The weighted sound velocity c avg is the sound velocity propagation speed of the limb part of this patient. Due to the different sound velocity propagation speeds in fat and muscle, this speed changes with the proportion of fat and muscle;

[0083] Conduct a correlation analysis on the weighted sound velocity c avg to generate a flow velocity deviation index L, and the formula is:

[0084]

[0085] where f dRepresents the Doppler frequency shift, which is used to reflect the difference between the received frequency and the transmitted frequency. f0 is the ultrasonic transmission frequency, θ is the angle between the propagation direction of the ultrasonic wave and the blood flow direction in Doppler ultrasound measurement, and 1540 is the value of the sound velocity in tissue in conventional Doppler ultrasound measurement. The formula for measuring blood flow velocity by Doppler ultrasound is as follows: By comparing with this formula, the deviation degree of blood flow velocity measured by Doppler ultrasound can be obtained. The flow velocity deviation index L is an index of the deviation degree of blood flow velocity measurement generated based on the muscle and fat thickness of the patient. The larger the value of the flow velocity deviation index L, the greater the deviation degree of the flow velocity calculation.

[0086] Step 7: Conduct a correlation analysis on the flow velocity deviation index L and the venous inner wall area deviation index S to generate a blood flow deviation index XLP. Compare the blood flow deviation index XLP with the threshold ∈, output the accuracy level of the blood flow measurement result based on Doppler ultrasound, and output whether to adopt the blood flow data measured by Doppler ultrasound.

[0087] The threshold ∈ is a set deviation degree threshold, which is obtained through experimental measurement. When the blood flow deviation index XLP is greater than this threshold, the data measured by Doppler ultrasound is defined as inaccurate. When the blood flow deviation index XLP is not greater than this threshold, the data measured by Doppler ultrasound is defined as accurate and can be adopted.

[0088] Conduct a correlation analysis on the flow velocity deviation index L and the venous inner wall area deviation index S to generate a blood flow deviation index XLP. The formula is as follows:

[0089] XLP = |(1 - S) * L|

[0090] The venous inner wall area deviation index S is a proportional value. When it is 1, it means that the data of the vascular cross-sectional area measured by Doppler ultrasound is accurate. The more it deviates from 1, the more inaccurate it is. The flow velocity deviation index L represents the calculation deviation degree of the blood flow velocity. By combining the two, the blood flow deviation index XLP is output. The blood flow deviation index XLP is used to reflect the error deviation degree of blood flow measurement based on Doppler ultrasound under the conventional tissue sound velocity. The larger the value of the blood flow deviation index XLP, the more inaccurate the data obtained by Doppler ultrasound measurement. When XLP ≤ ∈, the accuracy level of the blood flow measurement result based on Doppler ultrasound is output as level one, with a small deviation, and the blood flow data measured by Doppler ultrasound is adopted; when XLP > ∈, the accuracy level of the blood flow measurement result based on Doppler ultrasound is output as level two, with a large deviation, and the blood flow data measured by Doppler ultrasound cannot be adopted.

[0091] Refer to Figure 2, the present invention also provides a self - arteriovenous fistula monitoring system for hemodialysis patients, which is used to execute the self - arteriovenous fistula monitoring method for hemodialysis patients, including:

[0092] A limb model construction module, which is used to determine the vein to be monitored in the self - arteriovenous fistula, scan the limb where the vein is located by computer tomography, and construct a three - dimensional model of the limb;

[0093] A three - dimensional model analysis module, which is used to perform a correlation analysis on the three - dimensional model of the limb to generate a vein three - dimensional model, a fat three - dimensional model, and a muscle three - dimensional model;

[0094] A vein analysis module, which is used to place the three - dimensional model of the vein part in a coordinate system for correlation analysis to generate a vein area parameter, and perform a correlation analysis on the vein area parameter to generate a vein inner wall area deviation index;

[0095] A fat and muscle analysis module, which is used to reconstruct a three - dimensional coordinate system, place the fat three - dimensional model and the muscle three - dimensional model in the reconstructed three - dimensional coordinate system, where the emission direction of the Doppler ultrasonic wave coincides with the Z - axis, perform a correlation analysis on the fat three - dimensional model and the muscle three - dimensional model to generate a fat thickness and a muscle thickness, perform a correlation analysis on the fat thickness and the muscle thickness to generate a weighted sound velocity, and perform a correlation analysis on the weighted sound velocity to generate a flow velocity deviation index;

[0096] A comprehensive analysis module, which is used to perform a correlation analysis on the flow velocity deviation index L and the vein inner wall area deviation index S to generate a blood flow deviation index XLP, compare the blood flow deviation index XLP with a threshold ∈, output the accuracy level of the blood flow measurement result based on the Doppler ultrasonic wave, and output whether to adopt the blood flow data measured based on the Doppler ultrasonic wave.

[0097] The above formulas are all dimensionless and take their numerical values for calculation. The formulas are obtained by collecting a large amount of data for software simulation to get a formula closest to the real situation. The preset parameters in the formulas are set by those skilled in the art according to the actual situation.

[0098] The above - mentioned embodiments can be implemented in whole or in part by software, hardware, firmware, or any other combination. When implemented using software, the above - mentioned embodiments can be implemented in whole or in part in the form of a computer program product. Those skilled in the art can realize that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are executed by hardware or software methods depends on the specific application and design constraints of the technical solution.

[0099] The unit described as a separation component may or may not be physically separated. The component displayed as a unit may or may not be a physical unit, and it may be located in one place or distributed across multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0100] As described above, only the specific implementation manners of this application are provided, but the protection scope of this application is not limited thereto. Any person skilled in the art within the technical scope disclosed by this application can easily think of changes or substitutions, which should all be covered within the protection scope of this application.

Claims

1. A method for monitoring an autogenous arteriovenous fistula in hemodialysis patients, characterized in that, The specific steps include: S1. Determine the vein to be monitored in the autogenous arteriovenous fistula, scan the limb where the vein is located through computed tomography, and construct a three-dimensional model of the limb. S2. Conduct a correlation analysis on the three-dimensional model of the limb to generate a three-dimensional vein model, a three-dimensional fat model, and a three-dimensional muscle model. Among them, the three-dimensional vein model is used to reflect the three-dimensional model of the limb vein, the three-dimensional fat model is used to reflect the three-dimensional model of the limb fat, and the three-dimensional muscle model is used to reflect the three-dimensional model of the limb muscle. S3. Place the three-dimensional model of the vein part in a coordinate system for correlation analysis to generate vein area parameters, and the vein area parameters include the cross-sectional area of the vein and the mean area. S4. Conduct a correlation analysis on the vein area parameters to generate a vein inner wall area deviation index S, and the vein inner wall area deviation index S is used to reflect the deviation degree of the vein area measured by color Doppler ultrasound for the patient. S5. Reconstruct a three-dimensional coordinate system, place the three-dimensional fat model and the three-dimensional muscle model in the reconstructed three-dimensional coordinate system, where the emission direction of the Doppler ultrasound coincides with the Z-axis, and conduct a correlation analysis on the three-dimensional fat model and the three-dimensional muscle model to generate a fat thickness and a muscle thickness. The fat thickness is the effective fat thickness of the path during the transmission of the Doppler ultrasound, and the muscle thickness is the effective muscle thickness of the path during the transmission of the Doppler ultrasound. S6. Conduct a correlation analysis on the fat thickness and the muscle thickness to generate a weighted sound velocity, and conduct a correlation analysis on the weighted sound velocity to generate a flow velocity deviation index. The flow velocity deviation index is used to reflect the degree of blood flow measurement deviation caused by the muscle and fat thickness during the measurement of blood flow velocity by Doppler ultrasound. S7. Conduct a correlation analysis on the flow velocity deviation index L and the vein inner wall area deviation index S to generate a blood flow deviation index XLP, compare the blood flow deviation index XLP with a threshold ∈, output the accuracy level of the blood flow measurement result based on Doppler ultrasound, and output whether to adopt the blood flow data measured by Doppler ultrasound.

2. The method for monitoring the autogenous arteriovenous fistula of hemodialysis patients according to claim 1, wherein: Use 3DSlicer software to import the data obtained by computed tomography, use the threshold segmentation tool to extract the three-dimensional vein model, and extract the contours of the fat layer and the muscle through the threshold segmentation algorithm to generate the three-dimensional models of the fat and the muscle.

3. The method for monitoring the autogenous arteriovenous fistula of hemodialysis patients according to claim 1, wherein: The limb after autogenous arteriovenous fistula surgery is scanned by a CT scanner, and the collected data is processed by computer software to generate a three-dimensional model of the limb. The three-dimensional model is placed in the XYZ coordinate system, where the line connecting the head and tail endpoints of the vein is parallel to the Z axis, and the head endpoint of the vein is placed on the XOY plane. N equidistant cross-sections parallel to the XOY plane are set to truncate and divide the three-dimensional model of the vein, and the intersection lines of the inner three-dimensional model of the vein and the cross-sections are retained. Coordinate points are obtained from the intersection lines. The inner-vein coordinate points of the i-th cross-section are where i is used to index the cross-section, j is used to index the coordinate points obtained on that cross-section, the coordinate points on each cross-section are evenly spaced, and the number of coordinate points on each cross-section is M.

4. The method for monitoring the autogenous arteriovenous fistula of hemodialysis patients according to claim 3, wherein: Perform a correlation analysis on the coordinate points on the inner side of the vein to generate the vein cross-sectional area S i , and the formula used is: Among them, and are respectively defined as and to form a closed shape. The superscripts j and j + 1 are both used to index the coordinate points on the i-th cross-section. The venous cross-sectional area S i is used to reflect the area of the inner wall of the vein on the i-th cross-section; For the venous cross-sectional area S i perform a correlation analysis to generate the mean area The formula relied on is as follows: Mean area It is used to reflect the average area of the inner wall of the vein to be monitored in the autogenous arteriovenous fistula after segmentation; Perform a correlation analysis on the mean area to generate the venous inner wall area deviation index S. The formula used is as follows: Among them, D is the diameter of the blood vessel measured by color Doppler ultrasound, and the vein inner wall area deviation index S is used to reflect the deviation degree of the vein area measured by color Doppler ultrasound for the patient.

5. The method for monitoring the autogenous arteriovenous fistula of hemodialysis patients according to claim 2, wherein: The three-dimensional fat model is multi-layered. On the Z-axis, the fat layers are numbered. They are respectively the minimum coordinate point and the maximum coordinate point on the Z-axis where the k-th fat layer is located. There are a total of K fat layers. On the Z-axis, the muscle layers are numbered. They are respectively the minimum coordinate point and the maximum coordinate point on the Z-axis where the p-th muscle layer is located. There are a total of P muscle layers. A correlation analysis is performed on the three-dimensional fat model and the three-dimensional muscle model to generate the fat thickness Z and the muscle thickness R. The formula is as follows: α is the scaling ratio of the three-dimensional model to the entity. The fat thickness Z is used to reflect the thickness of the fat in the ultrasonic path during the measurement by Doppler ultrasound, and the muscle thickness R is used to reflect the thickness of the muscle in the ultrasonic path during the measurement by Doppler ultrasound.

6. The method for monitoring the autogenous arteriovenous fistula of hemodialysis patients according to claim 5, characterized in that: Perform a correlation analysis on the fat thickness and muscle thickness to generate the fat acoustic wave propagation time t Z and the muscle acoustic wave propagation time t R , and the formula used is: Among them, c Z is the propagation speed of sound waves in fat, and c R is the propagation speed of sound waves in muscle, which is obtained through laboratory measurement. The fat sound wave propagation time t Z is used to reflect the time when sound waves propagate in fat during Doppler ultrasound measurement, and the muscle sound wave propagation time t R is used to reflect the time when sound waves propagate in muscle during Doppler ultrasound measurement; For the acoustic wave propagation time t of fat Z and the acoustic wave propagation time t of muscle R perform a correlation analysis to generate a weighted sound velocity c avg , and the formula used is: Weighted sound velocity c avg The mean sound velocity used to reflect the Doppler sound velocity in the muscle and fat of this patient; Perform a correlation analysis on the weighted sound velocity c avg to generate a flow velocity deviation index L, and the formula used is as follows: where f d represents the Doppler frequency shift, which is used to reflect the difference between the received frequency and the transmitted frequency. f0 is the ultrasonic transmission frequency, θ is the angle between the propagation direction of the ultrasonic wave and the blood flow direction in Doppler ultrasound measurement, 1540 is the value of the sound velocity in tissue in conventional Doppler ultrasound measurement, and the flow velocity deviation index L is an index of the degree of deviation in blood flow velocity measurement generated based on the muscle and fat thickness of this patient.

7. The method for monitoring the autogenous arteriovenous fistula of hemodialysis patients according to claim 1, characterized in that: Conduct a correlation analysis on the flow velocity deviation index L and the vein inner wall area deviation index S to generate a blood flow deviation index XLP, and the formula is: XLP = |(1 - S) * L| The blood flow deviation index XLP is used to reflect the error deviation degree of blood flow measurement based on Doppler ultrasound at the sound speed of conventional tissues. When XLP ≤ ∈, the accuracy level of the blood flow measurement result based on Doppler ultrasound is output as grade one, with a small deviation, and the blood flow data measured by Doppler ultrasound is adopted; when XLP > ∈, the accuracy level of the blood flow measurement result based on Doppler ultrasound is output as grade two, with a large deviation, and the blood flow data measured by Doppler ultrasound cannot be used.

8. A self - arteriovenous fistula monitoring system for hemodialysis patients, which is used to execute the self - arteriovenous fistula monitoring method for hemodialysis patients described in claim 1, characterized in that, It includes: A limb model construction module, which is used to determine the vein to be monitored in the autogenous arteriovenous fistula, and construct a three-dimensional model of the limb by computer tomography scanning the limb where the vein is located; A three-dimensional model analysis module, which is used to perform a correlation analysis on the three-dimensional model of the limb to generate a three-dimensional vein model, a three-dimensional fat model, and a three-dimensional muscle model; A vein analysis module, which is used to place the three-dimensional model of the vein part in a coordinate system for correlation analysis to generate vein area parameters, and perform a correlation analysis on the vein area parameters to generate a vein inner wall area deviation index; A fat and muscle analysis module, which is used to reconstruct a three-dimensional coordinate system, place the three-dimensional fat model and the three-dimensional muscle model in the reconstructed three-dimensional coordinate system, where the emission direction of the Doppler ultrasound coincides with the Z-axis, perform a correlation analysis on the three-dimensional fat model and the three-dimensional muscle model to generate fat thickness and muscle thickness, perform a correlation analysis on the fat thickness and the muscle thickness to generate a weighted sound speed, and perform a correlation analysis on the weighted sound speed to generate a flow velocity deviation index; A comprehensive analysis module, which is used to perform a correlation analysis on the flow velocity deviation index L and the vein inner wall area deviation index S to generate a blood flow deviation index XLP, compare the blood flow deviation index XLP with the threshold ∈, output the accuracy level of the blood flow measurement result based on Doppler ultrasound, and output whether to adopt the blood flow data measured by Doppler ultrasound.

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