3D printing model generation system for patient-specific vascular intervention balloons

Abstract

The application discloses a 3D printing model generation system of a patient-specific vascular intervention balloon, which comprises an image modeling module, a balloon construction module, a stress adjustment module and a printing processing module.The image modeling module extracts vascular geometric and anatomical characteristic parameters from patient DICOM images and generates a three-dimensional model with anatomical characteristic annotations to provide a basis for balloon design.The balloon construction module marks high-risk areas and upgrades the model according to the vascular curvature and bending dynamics parameters in the three-dimensional model of the blood vessel to design an initial balloon three-dimensional model that fits the actual blood vessel.The stress adjustment module constructs a rule base covering various parameters of the balloon, optimizes the stress distribution of the balloon through simulation and prevents stress concentration.The printing processing module realizes material partition and density gradient control by using 3D printing according to the optimized balloon structure to manufacture a patient-specific balloon.The scheme can improve the adaptability of the balloon and the blood vessel, enhance the expansion effect, reduce the operation risk and provide strong support for personalized medical treatment.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric digital data processing, and in particular to a 3D printing model generation system for patient-specific vascular intervention balloons. BACKGROUND

[0002] In the design and manufacture of traditional vascular intervention balloons, standardized and universal products are often used, which are difficult to fully adapt to the unique vascular anatomy and physiological characteristics of each patient. The blood vessels of different patients differ significantly in geometry, vessel curvature, lesion location and degree, etc. The standardized balloon may not precisely fit the blood vessel, and problems such as inaccurate positioning and uneven pressure on the blood vessel wall may occur during the intervention treatment process, affecting the treatment effect and even causing complications such as blood vessel injury. Therefore, in order to meet the needs of personalized medicine, developing a technology that can generate customized balloons according to patient-specific vascular information has become a problem to be solved, which provides a realistic demand background for the emergence of a 3D printing model generation system for patient-specific vascular intervention balloons.

[0003] With the rapid development of medical imaging technology, DICOM images have become an important means of obtaining detailed information about a patient's blood vessels, providing high-precision geometric and anatomical feature parameters. However, how to effectively extract key information from these massive image data and convert it into a three-dimensional model that can be used for balloon design and manufacturing is one of the technical challenges currently faced. At the same time, in terms of balloon design, not only the adaptability of the balloon to the blood vessel needs to be considered, but also the mechanical properties of the balloon, such as stress distribution and stiffness gradient, need to be considered to ensure safety and effectiveness during treatment. The existing design and manufacturing methods are difficult to simultaneously meet these complex and personalized requirements. SUMMARY

[0004] The present application provides a 3D printing model generation system for patient-specific vascular intervention balloons, which includes an image modeling module, a balloon construction module, a stress adjustment module, and a printing processing module.

[0005] S1, the image modeling module is used to generate a three-dimensional model by extracting geometric and anatomical feature parameters from patient DICOM images.

[0006] S2, the balloon construction module is used to mark high-risk areas and upgrade the three-dimensional model of the blood vessel according to the curvature of the blood vessel in the three-dimensional model of the blood vessel and using bending dynamics parameters.

[0007] S3, the stress adjustment module is used to construct a rule base covering various parameters of the balloon and simulate and optimize the stress distribution of the balloon.

[0008] S4, the printing processing module is used for realizing material partition and density gradient control through 3D printing according to the optimized balloon structure, and manufacturing patient-specific balloon.

[0009] Preferably, the balloon construction module is further used for:

[0010] According to the curvature of the blood vessel in the three-dimensional model of the blood vessel and using the bending dynamics parameters, the high-risk area is accurately marked, and the three-dimensional model of the blood vessel is upgraded;

[0011] According to the upgraded three-dimensional model of the blood vessel, intelligent balloon design work is carried out, and a hinged structure adapted to the blood vessel is automatically segmented and generated;

[0012] The upper limit of the diameter growth rate of the curvature adaptation section and the upper limit of the pressure difference between adjacent sections are set, and the wall thickness of the non-load-bearing area is reduced;

[0013] For the key parts of the balloon, dynamic stiffness gradient printing control is realized.

[0014] Preferably, the balloon design includes: the design rules of the balloon model need to consider: balloon length, according to the length of the blood vessel stenosis section + two end safety margins, set the length of the blood vessel stenosis section as , the two end safety margins are both , then the balloon length is ; balloon diameter, refer to the target blood vessel diameter, set the proximal diameter of the stenosis section as , and the distal diameter as , then the balloon diameter is ; bending compliance, the balloon wall thickness of the high curvature area is thinned or the flexible material partition is used; bifurcation adaptation, the balloon at the complex bifurcation is designed as a double balloon or a side hole structure; calcification area strengthening, the spiral reinforcing rib or the thickened wall thickness is added to the balloon surface corresponding to the calcification area.

[0015] Preferably, the image modeling module includes:

[0016] Obtain the CT or MRI image of the blood vessel of the patient, use the U-Net neural network for automatic segmentation, identify the blood vessel boundary through the trained model, and output the binary mask of the blood vessel contour; wherein the blood vessel area is 1 and the background is 0;

[0017] Extract the blood vessel centerline through the skeletonization algorithm, calculate the curvature distribution of the centerline and mark the high curvature area, and generate the blood vessel centerline and the curvature distribution graph;

[0018] Mark the calcification area according to the HU value of the CT image, set the threshold to identify the position and range of plaque calcification, and generate the spatial coordinates and distribution graph of the calcification area;

[0019] Identify the bifurcation opening position and angle through blood vessel connectivity analysis, and mark the included angle of the branch blood vessel and the main blood vessel;

[0020] The segmented vascular contours, centerlines, calcification markers, and vascular branches are imported into the reconstruction software to generate a 3D model in STL format with geometric feature annotations.

[0021] Preferably, the upper limit of the diameter growth rate of the set curvature adaptation segment and the upper limit of the pressure difference between adjacent segments, while reducing the wall thickness of the non-load-bearing area, includes: setting the upper limit of the diameter growth rate of the set curvature adaptation segment. Diameter growth rate , must meet Set the upper limit of the pressure difference between adjacent sections. Pressure difference between adjacent sections Analyze the non-load-bearing area of ​​the balloon. Based on the overall strength requirements and material properties of the balloon, reduce the wall thickness of the non-load-bearing area. Assume the original wall thickness is... The wall thickness after reduction , where α is the reduction ratio.

[0022] Preferably, the stress adjustment module further includes:

[0023] Collect data on balloon size, shape, wall thickness distribution, material properties, and performance requirements under different working conditions, and logically correlate them to form a rule base covering multiple parameters of the balloon.

[0024] Determine the elastic modulus of the base material, and adjust the elastic modulus according to the actual application of the balloon material. ;

[0025] Based on the patient's vascular elastic modulus, the blood vessel is simplified into an isotropic elastomer;

[0026] Define the boundary conditions and applied loads for the simulation to determine the stress distribution;

[0027] Stress distribution simulation calculations were performed using finite element analysis software.

[0028] Analyze the stress distribution results obtained from the simulation calculation to identify areas of stress concentration and parts with unreasonable stress distribution.

[0029] Preferably, dynamic stiffness gradient printing control is implemented for key parts of the balloon, including: identifying key parts of the balloon, including hinge joints, curved inner walls, and curvature adaptation sections; using 3D printing technology for key parts, and by controlling the composition, density, and layer thickness parameters of the printing material, a mathematical model between material parameters and stiffness is established based on the required stiffness of each part, and the corresponding material parameters are calculated based on the model to guide the printing process.

[0030] Preferably, the system further includes: adjusting the elastic modulus of the base material according to the actually selected balloon material to obtain the elastic modulus of the actual balloon material. ; fixing both ends of the balloon before simulation, simulating the constraint state of the balloon when the catheter is pushed; gradually applying the rated working pressure of the balloon, observing the stress distribution; setting the friction coefficient μ between the balloon and the inner wall of the blood vessel, simulating the interaction between the balloon and the inner wall of the blood vessel during balloon expansion; according to the geometric shape, size and material properties of the balloon and the blood vessel, establishing a finite element model of the balloon and the blood vessel in the simulation software, and performing mesh division on the model; inputting boundary conditions, loads and material parameters into the simulation software, setting solving parameters; starting the simulation software to calculate and obtain the stress distribution results of the balloon under different working conditions.

[0031] Preferably, the intelligent balloon design work is carried out according to the upgraded three-dimensional model of the blood vessel, and a hinged structure adapted to the blood vessel is automatically generated in sections, including:

[0032] The spiral center line of the blood vessel is accurately extracted from the CTA image of the patient, the minimum curvature radius of the blood vessel is calculated, the ECG signal and the DSA contrast data of the patient are synchronously collected, and the spatiotemporal four-dimensional model is generated based on the synchronous data;

[0033] The three-dimensional model of the bifurcation of the blood vessel is reconstructed by using the CTA data, the vortex core center coordinates, the vortex influence radius and the pulsating vortex migration characteristics of the bifurcation are calculated by combining the spatiotemporal four-dimensional model and the hemodynamic principle, and the displacement vector and the migration angle of the bifurcation of the blood vessel in the systolic period are obtained by synchronously collecting the ECG signal and the ultrasonic Doppler data;

[0034] According to the overall shape of the blood vessel, the minimum curvature radius and the characteristics of the bifurcation of the blood vessel, the stress condition and the blood flow impact of the blood vessel are comprehensively considered, and the approximate number of the micro-grooves is calculated; the layout of the micro-grooves on the surface of the balloon is determined according to the spatial distribution rule of the blood vessel;

[0035] The hinge locking angle and the depth control law are determined by combining the biological rhythm of the blood vessel, the morphological change of the blood vessel and the layout of the micro-grooves, and the opening and closing logic is set so that the micro-grooves on the surface of the balloon can be dynamically adjusted according to the biological rhythm of the blood vessel.

[0036] Preferably, the spiral center line comprises:

[0037] The image segmentation algorithm is used to separate the blood vessel region from the background in the CTA image of the patient, and the spiral center line is extracted from the segmented blood vessel region by using the skeleton-based algorithm; wherein the accuracy of the spiral center line is required to be within ±0.1mm.

[0038] One or more technical solutions provided in the application have at least the following technical effects or advantages:

[0039] The three-dimensional model of the blood vessel with anatomical feature label is accurately generated by image modeling, and the initial balloon three-dimensional model is designed according to the actual condition of the blood vessel; the stress adjustment module optimizes the stress distribution of the balloon to avoid stress concentration; the printing processing module realizes material partition and density gradient control according to the optimization result, and manufactures the patient-specific balloon. The scheme improves the adaptability of the balloon and the blood vessel, enhances the expansion effect, reduces the operation risk, and provides strong support for personalized medical treatment.

[0040] The curvature of the three-dimensional model of the blood vessel is accurately extracted, the high-risk area is marked combined with the bending dynamics parameter, and the model is upgraded, on the basis of which intelligent balloon design is carried out, the adaptive hinge structure is automatically generated, the local performance is optimized, the curvature adaptation segment parameter is set, the non-bearing area wall thickness is reduced, and the dynamic stiffness gradient printing control of the key part of the balloon is realized, which effectively improves the fitting degree of the balloon and the blood vessel, ensures the uniform transmission of the expansion pressure, enhances the performance of the balloon in the complex blood vessel area, and at the same time reduces the weight and ensures the strength of the key part.

[0041] By accurately extracting the blood vessel information and constructing the space-time four-dimensional model, the blood vessel morphology, curvature and blood flow dynamics change can be clearly presented; the three-dimensional model of the blood vessel bifurcation is reconstructed and the related parameters are obtained, the blood vessel characteristics can be deeply understood; the layout and characteristics of the micro groove are determined by comprehensively considering various factors, which can improve the adaptability of the balloon and the blood vessel; the dynamic adjustment logic is set combined with biological rhythm, so that the balloon can better adapt to the physiological changes of the blood vessel, and the treatment effect and safety are improved. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 It is a structure schematic view of a 3D printing model generation system of a patient-specific vascular interventional balloon of an embodiment of the present application. DETAILED DESCRIPTION

[0043] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the related drawings; the preferred embodiments of the present application are shown in the drawings, but the present application can be realized in many different forms, and is not limited to the embodiments described herein; on the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0044] It should be noted that the terms "vertical", "horizontal", "up", "down", "left", "right" and similar expressions used herein are only for illustrative purposes and do not represent the only embodiment.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application; and the use herein of the terms "and / or" includes a combination of one or more of the associated listed items.

[0046] Embodiment one

[0047] Figure 1 A 3D printing model generation system of a patient-specific vascular intervention balloon according to an embodiment of the application.

[0048] As shown in Figure 1 , the 3D printing model generation system of the patient-specific vascular intervention balloon comprises an image modeling module, a balloon construction module, a stress adjustment module and a printing processing module.

[0049] In some embodiments, the 3D printing model generation system of the patient-specific vascular intervention balloon according to an embodiment of the application is specifically used to perform the following steps:

[0050] S1, the image modeling module is used to generate a three-dimensional model by extracting blood vessel geometric features and anatomical feature parameters from patient DICOM images.

[0051] Among them, the anatomical feature parameters are the curvature, calcification position and bifurcation angle of the blood vessel.

[0052] Specifically, the CT or MRI image of the patient's blood vessel is obtained, the U-Net neural network is used for automatic segmentation, the blood vessel boundary is identified by training the model, and the binary mask of the blood vessel contour is output (the blood vessel region is 1 and the background is 0).

[0053] The centerline of the blood vessel is extracted by the skeletonization algorithm, the curvature distribution of the centerline is calculated and the high curvature area is marked, and the centerline and the curvature distribution graph of the blood vessel are generated. Specifically, the skeletonization algorithm (Zhang-Suen thinning algorithm) is applied to the binary mask, the centerline of the blood vessel (single-pixel width skeleton) is extracted, the discrete points are sampled along the centerline, the curvature of each point is calculated, and the area with curvature higher than the threshold (appropriately adjusted according to the actual application) is marked as the high curvature section.

[0054] Among them, the curvature calculation formula is: for three consecutive points on the centerline, the curvature is calculated as follows:

[0055]

[0056] Among them, L is the distance between points, and Area is the area of the triangle formed by three points.

[0057] According to the HU value of the CT image, the calcification region is marked, the threshold value is set to identify the position and range of plaque calcification, and the spatial coordinates and distribution diagram of the calcification region are generated. Specifically, according to the HU value distribution of the CT image, the calcification threshold value (the threshold value HU>130 is defined in this application, which can be adjusted appropriately according to the actual application) is set, the voxels in the scanned image that meet the threshold value are marked as calcification regions, and the spatial coordinate set and range boundary of the calcification region are generated.

[0058] Among them, the calcification voxel screening is realized by threshold comparison: .

[0059] The bifurcation opening position and angle are identified by analyzing the vascular connectivity, and the included angle between the branch vessels and the main vessels is marked. Specifically, the connectivity analysis is performed on the vascular skeleton to identify the bifurcation point (the skeleton point connecting more than two branches), and the included angle between the branch vessels and the main vessels is calculated: at the bifurcation point, the main vessel direction vector and the branch direction vector are taken. The included angle is calculated by vector dot product, and the bifurcation opening position and angle are marked (the included angle <60° is an acute angle bifurcation).

[0060] The segmented blood vessel contour, center line, calcification mark and blood vessel branch are imported into the reconstruction software to generate an STL format three-dimensional model with geometric feature annotation. Specifically, the segmented blood vessel contour (binary mask), center line (including curvature annotation), calcification region (spatial coordinates) and bifurcation structure (angle and position) are imported into the three-dimensional reconstruction software, and the surface rendering algorithm (MarchingCubes) is used to generate a blood vessel surface mesh model. The anatomical feature parameters (curvature distribution, calcification mark, bifurcation angle) are attached to the model surface in the form of texture or attribute, and exported as an STL format file (triangular mesh model).

[0061] S2, the balloon construction module is used to mark the high-risk area according to the vascular curvature in the three-dimensional model of the blood vessel and use the bending dynamics parameters, and upgrade the three-dimensional model of the blood vessel.

[0062] Among them, the design rules of the balloon model need to be considered: the length of the balloon, according to the length of the stenosis segment of the blood vessel + the safety margin at both ends (assuming the length of the stenosis segment of the blood vessel is , and the safety margin at both ends is , then the length of the balloon is ; the diameter of the balloon, referring to the target blood vessel diameter (assuming the diameter of the proximal end of the stenosis segment is , and the diameter of the distal end is , then the diameter of the balloon is ) ; bending compliance, balloon wall thickness reduction of 20-30% in high curvature areas, or sub-division of the balloon with flexible material; bifurcation adaptation, balloon design with "double balloon" or "side hole structure" in complex bifurcations; calcification area reinforcement, spiral reinforcement or thickened wall thickness on the balloon surface corresponding to the calcification area.

[0063] The initial balloon three-dimensional model includes length, diameter, bending section, bifurcation section, and calcification area reinforcement structure.

[0064] Specifically, a three-dimensional model of the blood vessel is constructed, and anatomical feature parameters such as the length of the stenosis section of the blood vessel, the diameters of the proximal and distal ends of the stenosis section, the curvature distribution of the blood vessel, whether there is a complex bifurcation, and the location of the calcification area are extracted from the model. According to the length of the stenosis section of the blood vessel, combined with the safety margin at both ends (the safety margin can be set according to actual clinical experience, for example, 5mm at each end), the length of the balloon is calculated. The average diameter of the proximal and distal ends of the stenosis section is calculated, multiplied by 1.1 as a reference value to determine the diameter of the balloon. The curvature distribution of the blood vessel is analyzed to identify high curvature areas. For high curvature areas, there are two ways to handle them: one is to reduce the balloon wall thickness by 20-30%; the other is to subdivide the area with flexible material. Check if there is a complex bifurcation in the blood vessel, if there is, design the balloon at the complex bifurcation as "double balloon" or "side hole structure". Determine the location of the calcification area in the blood vessel, and add spiral reinforcement or thickened wall thickness on the balloon surface corresponding to the calcification area. Integrate the balloon length, diameter, bending section processing method, bifurcation section design, and calcification area reinforcement structure determined above, and generate an initial balloon three-dimensional model according to the design rules of the balloon model.

[0065] For example, a patient is admitted to the hospital due to chest pain, and coronary angiography shows that there is a significant stenosis in the left anterior descending branch (LAD) of the patient, which needs to be treated by balloon dilation. The doctor needs to construct an initial balloon three-dimensional model according to the specific situation of the diseased blood vessel. Through coronary angiography and subsequent blood vessel reconstruction technology, a three-dimensional blood vessel model of the patient's left anterior descending branch (LAD) is constructed.

[0066] The following anatomical feature parameters are accurately extracted from the model: the length of the stenosis section of the blood vessel , the diameter of the proximal end of the stenosis section , and the diameter of the distal end . The curvature distribution of the blood vessel shows that there is a high curvature area about 5mm behind the stenosis section. There is a complex bifurcation located 8mm distal to the stenosis section. The calcification area is located in the middle of the stenosis section, with a length of about 5mm.

[0067] Set the safety margin at both ends (determined according to clinical experience and the condition of the diseased blood vessel), according to the balloon length calculation formula , the length of the balloon can be obtained. First, calculate the average diameter of the proximal and distal ends of the stenosis section According to the balloon diameter calculation formula , the balloon diameter is , and for convenience of actual operation, it is rounded to 3.2 mm.

[0068] For the high curvature area, the balloon wall thickness of the area is reduced by 25% (an intermediate value is selected within the range of 20%-30%). Assuming that the normal balloon wall thickness is 0.1 mm, the balloon wall thickness of the high curvature area becomes 0.1 x (1-25%) = 0.075 mm. Due to the complex bifurcation, the balloon at the complex bifurcation is designed as a "double balloon" structure. That is, the main balloon is used to expand the stenosis section, and a smaller side balloon extends at the bifurcation, with a diameter of 2.0 mm and a length of 8 mm to better adapt to the morphology of the bifurcated blood vessels. A spiral reinforcing rib is added to the surface of the balloon corresponding to the calcified area (length 5 mm). The spiral reinforcing rib is made of the same material as the balloon, with a width of 0.5 mm and a pitch of 1 mm to enhance the expansion capacity and damage resistance of the balloon in the calcified area.

[0069] Based on the above-determined balloon length of 21 mm, diameter of 3.2 mm, bending section (high curvature area wall thickness of 0.075 mm), bifurcation section ("double balloon" structure, side balloon diameter of 2.0 mm, length of 8 mm), and calcified area strengthening structure (spiral reinforcing rib with a length of 5 mm), an initial balloon three-dimensional model is generated using three-dimensional modeling software (SolidWorks, Mimics, etc.) according to the design rules of the balloon model.

[0070] In some embodiments, step S2 further includes the following content:

[0071] S21, according to the curvature of the blood vessel in the three-dimensional model of the blood vessel and using the bending dynamics parameters, accurately mark the high-risk area, and upgrade the three-dimensional model of the blood vessel.

[0072] Specifically, the curvature of the blood vessel is extracted from the three-dimensional model of the blood vessel and the bending dynamics parameters are used. The curvature can be obtained by calculating the curvature radius of each point on the center line of the blood vessel, and the bending dynamics parameters can be calculated in combination with the blood flow hemodynamic characteristics related data.

[0073] Along the center line of the blood vessel, the curvature radius is accurately calculated at every 2 mm interval, and the blood vessel section with a curvature greater than 30° is marked as a high-risk bending section, and the error is strictly controlled to be ≤0.5°. The curvature calculation formula is: let the tangent direction vector of a point on the center line of the blood vessel be , the normal direction vector be , and the curvature be (where s is the arc length parameter), and the curvature angle θ = arctan(k) (here it is simplified to be measured by angle, and the actual calculation is more complex, which needs to consider factors such as unit conversion).

[0074] The minimum bending radius R_min of the blood vessel was measured. When R_min < 20 mm, the area was marked and articulation design was initiated. The anatomical locations of the inner and outer walls of the bend were marked with an accuracy of ±0.1 mm. Based on the standard 3D blood vessel model, an upgrade was made by adding a bend-sensitive area and clearly marking blood vessel segments with curvature greater than 30°. A detailed wall thickness distribution map was drawn, and the "compression-resistant zone" was marked on the outer wall of the bend, and the "tensile-resistant zone" was marked on the inner wall, providing accurate vascular structural information for subsequent balloon design.

[0075] S22, based on the upgraded 3D model of blood vessels, carries out intelligent balloon design work, automatically segmenting and generating articulated structures that adapt to blood vessels.

[0076] The intelligent design of the balloon encompasses several key aspects, including automatically generating articulated structures, locally thickening the curved inner wall, and optimizing segmented articulations and curved surfaces, to achieve a perfect fit between the balloon structure and the blood vessel.

[0077] Specifically, based on vascular characteristics, the system automatically segments and generates articulated structures, ensuring that the number of segments n ≥ 3. The number of segments can be determined based on the total length L of the vascular vessel and a preset range of segment lengths. ,pass ( The initial estimate is based on the preset average segment length, and then adjusted according to the actual condition of the blood vessel. A local thickening of 25% is applied to the curved medial wall, assuming the original wall thickness is... After thickening the wall thickness This effectively compensates for the compressive stress that the area may experience during balloon expansion. The gooseneck hyperboloid topology is activated, and an optimized algorithm ensures a balloon-vascular fit of ≥92%. Fit can be calculated by measuring the overlap area between the balloon surface and the vessel wall. Total area of ​​the inner wall of blood vessels ratio To measure and ensure that the expansion pressure is evenly transmitted. Set the segment length ratio to not exceed 1.3, and let the lengths of adjacent segments be respectively... and ,but To prevent sudden stress changes due to excessive differences in segment length, the stiffness of the near-end segment is adjusted from... The value changes from 5.0 N·mm² to the distal end. 0.8 N·mm², achieving a gradual gradient of 84%. Stiffness variation can be achieved using a linear variation formula. ( (The length from the proximal end to the current position) allows the balloon to have appropriate stiffness at different locations. In regions with a radius of curvature R < 30 mm, a hyperboloid expansion surface is generated. The shape of the hyperboloid can be obtained through the standard equation of hyperboloids, further improving the balloon's performance in this complex region.

[0078] S23, set the diameter growth rate upper limit of the curvature adaptation section and the pressure difference upper limit of adjacent segments, while reducing the wall thickness of the non-load-bearing area.

[0079] Specifically, set the diameter growth rate upper limit of the curvature adaptation section (the diameter growth rate of the present application is not more than 0.15 mm / s), and the specific value can be determined according to the tolerance of the blood vessel and the design requirements of the balloon. The diameter growth rate , needs to meet . Set the pressure difference upper limit of adjacent segments (the present application defines 0.4 atm), the pressure difference can be measured by a pressure sensor or calculated according to the principle of fluid dynamics, and needs to ensure that the pressure difference between adjacent segments . Analyze the non-load-bearing area of the balloon, reduce the wall thickness of the non-load-bearing area according to the overall strength requirements of the balloon and the material properties, and set the original wall thickness (the reduction ratio α is determined according to the actual situation), it needs to be explained that the wall thickness of the non-load-bearing area is reduced to maintain the bending area wall thickness of 0.05 mm, while reducing the weight of the balloon and ensuring the strength of the key parts.

[0080] S24, for the key parts of the balloon, realize dynamic stiffness gradient printing control.

[0081] Among them, the key parts of the balloon are clearly defined, including the hinge joint, the bending inner wall, and the curvature adaptation section. For these key parts, 3D printing technology is used to control the composition, density, layer thickness and other parameters of the printing material to realize dynamic stiffness gradient printing control. Specifically, according to the required stiffness of each part, a mathematical model between material parameters and stiffness can be established, such as the relationship between the stiffness and the material density (A and n are material constants), and the corresponding material parameters are calculated according to the model to guide the printing process.

[0082] It needs to be explained that by accurately extracting the curvature of the three-dimensional model of the blood vessel and marking the high-risk area combined with the bending dynamics parameters and upgrading the model, intelligent balloon design is carried out based on this to automatically generate adaptive hinge structure, optimize local performance, set curvature adaptation section parameters, reduce non-load-bearing area wall thickness and realize dynamic stiffness gradient printing control of the key parts of the balloon, effectively improve the fit of the balloon and the blood vessel, ensure uniform transmission of expansion pressure, and enhance the performance of the balloon in complex blood vessel regions, while reducing weight and ensuring the strength of the key parts.

[0083] S3, stress adjustment module is used to build a rule base covering various parameters of the balloon, and simulate and optimize the stress distribution of the balloon.

[0084] Specifically, the size, shape, wall thickness distribution, material characteristic parameters of the balloon and performance requirements under different working conditions are collected to form a rule base covering various parameters of the balloon.

[0085] Determine the elastic modulus of the base material, and adjust the elastic modulus according to the actual application balloon material Specifically: according to the actual selected balloon material (may be a material modified or compounded on the basis of the base material), combined with the modification process of the material, the change of the composition and other factors, the elastic modulus of the base material is adjusted to obtain the elastic modulus of the actual balloon material For example, if the base material is a certain polymer, the elastic modulus is increased by adding reinforcing fibers, which can be estimated and adjusted according to the proportion of added fibers and the elastic modulus of the fibers using the mixing law formula.

[0086] Simplify the blood vessel as an isotropic elastic body according to the elastic modulus of the patient's blood vessel. Specifically: the elastic modulus of the patient's blood vessel is obtained by measuring the medical imaging technology (intravascular ultrasound, magnetic resonance elastography) Simplify the blood vessel as an isotropic elastic body, that is, consider the elastic properties of the blood vessel in all directions to be the same.

[0087] Define the boundary conditions and load applied force of the simulation to determine the stress distribution. Specifically, fix both ends of the balloon before simulation to simulate the constraint state of the balloon when the catheter is pushed; gradually apply the rated working pressure of the balloon to observe the stress distribution; make the friction coefficient μ between the balloon and the inner wall of the blood vessel to simulate the interaction between the balloon and the inner wall of the blood vessel when the balloon is expanded. The friction coefficient can be measured by experiment or obtained by referring to relevant literature.

[0088] Use finite element analysis software (such as ANSYS, Abaqus, etc.) to perform stress distribution simulation calculation. According to the geometric shape, size and material properties of the balloon and the blood vessel, establish a finite element model of the balloon and the blood vessel in the simulation software, and divide the model into grids. The density of the grid will affect the calculation accuracy and calculation time, and reasonable selection should be made according to the actual situation. Input the boundary conditions, load and material parameters determined in the previous step into the simulation software, and set the solution parameters such as solution method and convergence criterion. Start the simulation software to calculate and get the stress distribution results of the balloon under different working conditions.

[0089] Analyze the stress distribution results obtained by simulation calculation, and find out the stress concentration area and unreasonable stress distribution parts. According to the analysis results, adjust the related parameters of the balloon, such as wall thickness distribution, shape structure, etc., and re-calculate the simulation until the stress distribution meets the design requirements, and the stress distribution is optimized.

[0090] S4, the printing processing module is used for realizing material partition and density gradient control through 3D printing according to the optimized balloon structure, and manufacturing a patient-specific balloon.

[0091] Specifically, according to the balloon structure optimized by the stress adjustment module, the high stress areas on the balloon are determined through the finite element analysis results. These areas bear large stress during the balloon expansion process and need to enhance the material performance. For the high stress areas, a composite material of TPU and 20% nylon is prepared. The TPU base material and the nylon are mixed uniformly according to the proportion, and the nylon can be dispersed well in the TPU through methods such as melt blending to improve the Young's modulus of the material in this area by 3 times. In the 3D printing software, according to the balloon structure model, the high stress areas and other areas are accurately divided. The high stress areas use the above-mentioned composite material, and the other areas use ordinary TPU material.

[0092] The balloon structure is analyzed to find out the areas where the wall thickness changes, such as the bending compliance processing area, the calcification area strengthening structure and the normal wall thickness transition area, etc. The density gradient range of the wall thickness change area is set to 0.8-1.2 g / cm³, and its continuous transition mode is determined. The density gradient change can be realized by adjusting the material filling density in the 3D printing process, and the filling density is related to the actual density of the material. In the 3D printing slicing software, for the wall thickness change area, the corresponding density gradient parameters are set, so that the software can generate appropriate printing path and filling mode according to these parameters.

[0093] According to the needs of the calcification area strengthening in the balloon structure, the shape, size and pitch of the spiral reinforcing rib and other parameters are designed. For example, the width, height and spacing between adjacent two circles of the spiral reinforcing rib are determined. The G-code generation algorithm is used: a special G-code generation algorithm is used, which combines the design parameters of the spiral reinforcing rib and the overall structure of the balloon, to calculate the accurate stacking path of the spiral reinforcing rib on the balloon surface. This algorithm needs to consider the moving track of the printing head, the material extrusion amount and other factors to ensure that the spiral reinforcing rib can be accurately and firmly printed on the balloon. Generate a complete G-code file: integrate the information of material partition, density gradient control and spiral reinforcing rib path planning to generate a complete G-code file. This file contains all the instructions required by the 3D printer during the printing process, such as the moving coordinates of the printing head, the material extrusion speed, the temperature control, etc.

[0094] Check the performance indicators of the 3D printer to ensure normal operation. Install the appropriate printing nozzle, set the printing temperature, printing platform temperature and other parameters according to the selected material. Put the prepared ordinary TPU material and TPU+20% nylon composite material into the corresponding material groove of the 3D printer respectively. Import the generated G-code file into the 3D printer for the last check and calibration before printing to ensure the accuracy of the printing position. Start the 3D printer and print according to the instructions of the G-code file. During the printing process, pay close attention to the printing status and handle possible problems such as material blockage and printing layer misalignment in a timely manner. After printing, remove the balloon from the printing platform and perform necessary post-processing operations such as removing support structures and surface polishing to obtain a smooth and accurately sized patient-specific balloon.

[0095] wherein the Young's modulus of the ordinary TPU material is , the Young's modulus of the TPU+20% nylon composite material in the high stress area is 3 times that of the ordinary TPU material, then the Young's modulus of the composite material is ; assuming that the actual density of the material is and the filling density is (the filling density value range is usually between 0-1), there is an approximate linear relationship between them, that is , wherein is the maximum density when the material is completely filled. In the wall thickness change area, the value of is adjusted to realize the continuous transition of the density in the range of 0.8-1.2 g / cm³. For example, when the density is , the corresponding filling density can be calculated according to .

[0096] The technical solutions in the above embodiments of the present application have at least the following technical effects or advantages:

[0097] The image modeling accurately generates a blood vessel three-dimensional model with anatomical feature labeling, and accordingly an initial balloon three-dimensional model is designed to fit the actual condition of the blood vessel. The stress adjustment module optimizes the stress distribution of the balloon to avoid stress concentration. The printing processing module realizes material partitioning and density gradient control according to the optimization results to manufacture a patient-specific balloon. This scheme improves the adaptability of the balloon to the blood vessel, enhances the expansion effect, reduces the risk of surgery, and provides strong support for personalized medical treatment.

[0098] Embodiment Two

[0099] In embodiment one, by constructing a three-dimensional model of the blood vessel and based on its anatomical feature parameters and bending dynamics parameters, intelligent balloon design is carried out, the balloon and the blood vessel are well matched, and the stress distribution is optimized, and a patient-specific balloon is manufactured through 3D printing. However, in actual application scenarios, the blood vessel conditions of different patients are different, the complexity of the blood vessel, the diversity of the lesion site and the physiological differences of individuals, etc. Factors such as the balloon generated according to the unified design process and parameters are difficult to achieve the optimal performance when facing various special blood vessel conditions. For example, for some patients with extremely twisted blood vessels, multiple severe calcification and complex bifurcation, the balloon manufactured according to the conventional design method may not be able to uniformly transmit pressure during expansion, resulting in insufficient expansion in some areas and excessive expansion in some areas, thereby affecting the treatment effect, and even may cause damage to the blood vessel. Moreover, the elastic modulus and blood flow dynamics characteristics of different patients' blood vessels also have great differences, and these factors will have an important influence on the design and use of the balloon. In order to further improve the adaptability of the balloon to various complex blood vessel conditions and the treatment effect, and to provide more accurate and personalized treatment for patients, more factors need to be considered, and the balloon design and manufacturing process need to be further optimized and improved, so embodiment two is proposed.

[0100] Therefore, the embodiments of the present application make certain optimizations on the basis of the above-mentioned embodiments.

[0101] In some embodiments, step S22 further comprises:

[0102] S221, accurately extracting the spiral centerline of the blood vessel from the CTA image of the patient, calculating the minimum curvature radius of the blood vessel, synchronously collecting the ECG signal and DSA contrast data of the patient, and generating a spatiotemporal four-dimensional model based on the synchronous data.

[0103] Specifically, the image segmentation algorithm is used to separate the blood vessel region and the background from the CTA image of the patient, and the skeleton-based algorithm (thinning algorithm) is used to extract the spiral centerline from the segmented blood vessel region, ensuring that the extraction accuracy is within ±0.1mm.

[0104] A series of discrete points are selected along the spiral centerline, and local fitting (such as quadratic polynomial fitting) is performed on each point and its adjacent points. (taking the fitting curve of y with respect to x as an example), and then the curvature radius is obtained. Find the minimum value in all curvature radii, and set the critical threshold to 20mm to judge the blood vessel high curvature area.

[0105] Connect the ECG device and set the heart rate monitoring range to 60-180 bpm. Real-time acquisition of patient ECG signals. Synchronously start the DSA device and collect DSA contrast data, ensuring that the ECG signal and DSA contrast data are time-synchronized. Based on the synchronously collected ECG signal and DSA contrast data, each heartbeat cycle is carefully divided into 50 phases. According to the spiral centerline and curvature radius data of the blood vessel, the change in curvature during systole is labeled, for example, at a specific heart rate (such as 120 bpm), the amount of curvature change ΔR is recorded. Combined with the blood flow information in the DSA contrast data, the vortex migration rate during diastole is calculated and labeled, ranging from 0.3 to 1.8 mm / s. Use all the above data to construct a spatiotemporal four-dimensional model to show the shape, curvature change, and hemodynamic characteristics of the blood vessel at different heartbeat phases.

[0106] S222, using CTA data to reconstruct a three-dimensional model of the blood vessel bifurcation, combining the spatiotemporal four-dimensional model and hemodynamic principles to calculate the vortex core coordinates, vortex influence radius, and pulsatile vortex migration characteristics at the bifurcation; synchronously collect ECG signals and ultrasound Doppler data to obtain the displacement vector and migration angle of the blood vessel bifurcation during systole.

[0107] Wherein, the systolic displacement vector is the peak systolic velocity, and the migration angle is the direction of the dynamic vortex core movement.

[0108] S223, according to the overall shape of the blood vessel, the minimum curvature radius, and the characteristics of the blood vessel bifurcation, comprehensively consider the stress condition of the blood vessel and the impact of blood flow, calculate the approximate number of micro-grooves; according to the spatial distribution rule of the blood vessel, determine the layout of the micro-grooves on the balloon surface.

[0109] Wherein, the spatial distribution rule is the spatial trend, curvature change, and bifurcation position of the blood vessel,

[0110] If located on the outside of the curvature (R>30mm), adopt a spiral arrangement, with a pitch of 0.8xD; if located on the inside of the high curvature (R≤30mm), adopt a radial arrangement, with a divergence angle β=360° / N. According to the constraint conditions, the geometric characteristics of the radial grooves on the inside of the curvature (depth 0.12mm, inclination angle 25°±5°) and the spiral grooves on the outside of the curvature (depth 0.08mm, inclination angle 40°±5°) are designed, including parameters such as length.

[0111] S224, combined with the biological rhythm of the blood vessel, the morphological change of the blood vessel, and the layout of the micro-grooves, determine the hinge locking angle and depth control law, set the opening and closing logic so that the micro-grooves on the balloon surface can be dynamically adjusted according to the biological rhythm of the blood vessel.

[0112] Wherein, the biological rhythm of the blood vessel is reflected by the ECG signal, and the morphological change of the blood vessel is provided by the space-time four-dimensional model; the depth control law enables the micro-groove on the surface of the balloon to adjust the depth according to the contraction and dilation dynamics of the blood vessel.

[0113] For example, the image segmentation algorithm (such as the threshold-based segmentation method, which sets the appropriate gray threshold range to distinguish blood vessels and background tissues) is used to separate the blood vessel region and the background from the CTA image of the patient. The skeleton-based thinning algorithm is used to extract the spiral centerline from the segmented blood vessel region, and the boundary pixels are removed through multiple iterations to ensure that the extraction accuracy is within ±0.1 mm. According to the measurement, the spiral centerline extraction error of the target blood vessel segment is controlled within the specified range. A series of discrete points are selected along the spiral centerline every 1 mm, and a local quadratic polynomial fitting is performed on each point and its adjacent 5 points. The curvature is calculated according to the fitting curve, and the formula is Further, the radius of curvature is obtained. The minimum value of all the radii of curvature is 18 mm, and the critical threshold is set to 20 mm, so as to judge that there is a high curvature region in the blood vessel segment.

[0114] Connect the ECG device and set the heart rate monitoring range to 60-180 bpm to collect the ECG signal of the patient in real time. Mr. Li's heart rate is stable at about 75 bpm during the collection process. Start the DSA device synchronously, collect the DSA contrast data, and ensure that the ECG signal and the DSA contrast data are time-synchronized. Based on the synchronously collected data, each heartbeat cycle is carefully divided into 50 phases. According to the spiral centerline and the radius of curvature data of the blood vessel, the change of the curvature in the systolic period is labeled. For example, at a heart rate of 75 bpm, the change of the curvature at a certain position is recorded as ΔR = ±0.8 mm. Combined with the blood flow information in the DSA contrast data, the diastolic vortex migration rate is calculated and labeled, and the measured diastolic vortex migration rate of the blood vessel segment is 0.5-1.2 mm / s. Using all the above data, a space-time four-dimensional model is constructed, which can clearly show the morphology, curvature change and hemodynamic characteristics of the blood vessel at different heartbeat phases on the computer screen. It can be seen that in the high curvature region, the blood vessel morphology changes obviously, the systolic curvature increases, and the diastolic vortex migration rate is relatively fast.

[0115] The three-dimensional model of the blood vessel bifurcation is reconstructed using the CTA data, and the space-time four-dimensional model and the hemodynamic principle (the flow of blood at the bifurcation is simulated according to the fluid mechanics equation) are combined to calculate the vortex core coordinates, the vortex influence radius and the pulsating vortex migration characteristics at the bifurcation. According to the calculation, the vortex core coordinates at the bifurcation of the blood vessel are (Actual coordinates are determined according to actual calculation), the eddy current influence radius is 2.5 mm, and the pulsatile eddy migration characteristic is periodic fluctuation within a certain range. The ECG signal and ultrasonic Doppler data are synchronously collected to obtain the displacement vector and migration angle of the bifurcation of the blood vessel in the systolic period. The peak flow velocity in the systolic period is 80 cm / s, which is the size of the displacement vector in the systolic period, and the migration angle is the angle between the moving direction of the dynamic vortex core and the axial direction of the blood vessel, which is measured to be 30°.

[0116] According to the overall shape of the blood vessel (obtained from the space-time four-dimensional model and the three-dimensional model), the minimum curvature radius (18 mm) and the characteristics of the blood vessel bifurcation (vortex core coordinates, eddy current influence radius, etc.), the stress condition of the blood vessel (analyzed according to the stress-strain relationship of the blood vessel wall) and the blood flow impact (combined with the hemodynamic simulation results) are comprehensively considered to calculate the approximate number of micro grooves. According to the calculation, it is preliminarily determined that about 50 micro grooves are needed. According to the spatial distribution rule of the blood vessel (the spatial trend of the blood vessel, the curvature change and the bifurcation position, etc.), the layout of the micro grooves on the balloon surface is determined. The part of the blood vessel segment is located on the outside of the curvature (R=35 mm>30 mm), and the spiral arrangement mode is adopted, and the pitch is set to 0.8xD (D is the diameter of the blood vessel, which is measured to be 3 mm, so the pitch is 0.8x3=2.4 mm); part of the area is located on the inside of the high curvature (R=18 mm≤30 mm), and the radial arrangement mode is adopted, and the divergence angle β=360° / N (N is the number of micro grooves in this area, which is calculated to be 20, so β=360°÷20=18°). According to the constraint condition, the geometric characteristics of the curvature inside radial groove (depth 0.12 mm, inclination angle 25°±5°, the inclination angle is determined to be 25° after optimization) and the curvature outside spiral groove (depth 0.08 mm, inclination angle 40°±5°, the inclination angle is determined to be 40° after optimization) are designed, and the length is determined to be 5 mm according to the length of the blood vessel segment and the arrangement mode.

[0117] Combining the biological rhythm of blood vessels (reflected by the ECG signal, heart rate 75bpm), the morphological changes of blood vessels (provided by the spatiotemporal four-dimensional model, such as the changes of blood vessel diameter in systole and diastole, etc.), and the microgroove layout, the hinge locking angle is determined to be 45° through mechanical analysis and simulation experiments, which can ensure that the balloon can stably adhere to the blood vessel during the opening and closing process. The depth control law is set so that the microgroove on the surface of the balloon can adjust the depth according to the contraction and diastolic dynamics of the blood vessel. For example, when the blood vessel contracts, the change of the blood vessel diameter is detected through the sensor, and the depth of the microgroove is reduced by 0.02mm; when the blood vessel diastolic, the depth of the microgroove is increased by 0.02mm. The opening and closing logic is set so that the microgroove on the surface of the balloon can adjust according to the biological rhythm of the blood vessel. Taking the R wave of the ECG signal as the trigger point, when the R wave is detected, the contraction process of the balloon starts, and the microgroove adjusts the depth according to the depth control law; when the next R wave is detected, the diastolic process of the balloon starts, and the microgroove adjusts the depth again. In this way, the microgroove on the surface of the balloon is matched with the biological rhythm of the blood vessel, and the adaptability of the balloon to the blood vessel and the treatment effect are improved.

[0118] The technical solutions in the embodiments of the present application have at least the following technical effects or advantages:

[0119] By accurately extracting blood vessel information and constructing a spatiotemporal four-dimensional model, the morphological changes, curvature and hemodynamic changes of the blood vessel can be clearly presented; by reconstructing the three-dimensional model of the blood vessel bifurcation and obtaining related parameters, the characteristics of the blood vessel can be deeply understood; by considering various factors to determine the microgroove layout and characteristics, the adaptability of the balloon to the blood vessel can be improved; by combining the biological rhythm and setting the dynamic adjustment logic, the balloon can better adapt to the physiological changes of the blood vessel, and the treatment effect and safety can be improved.

[0120] The above only describes the preferred embodiments of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A system for generating a 3D printed model of a patient-specific vascular intervention balloon, characterized in that, The application relates to a medical balloon design system, which comprises an image modeling module, a balloon construction module, a stress adjustment module and a printing processing module. S1, the image modeling module is used for extracting blood vessel geometric features and anatomical feature parameters from patient DICOM images to generate a three-dimensional model; S3, the stress adjustment module is used for constructing a rule base covering various parameters of the balloon, and simulating and optimizing stress distribution of the balloon; S2, the balloon construction module is used for marking the high-risk area according to the curvature of the blood vessel in the three-dimensional model of the blood vessel and using the bending dynamics parameters, and upgrading the three-dimensional model of the blood vessel; specifically: according to the curvature of the blood vessel in the three-dimensional model of the blood vessel and using the bending dynamics parameters, the high-risk area is accurately marked, and the three-dimensional model of the blood vessel is upgraded; according to the upgraded three-dimensional model of the blood vessel, intelligent balloon design work is carried out, and the articulated structure adapted to the blood vessel is automatically segmented; the upper limit of the diameter growth rate of the curvature adaptation section and the upper limit of the pressure difference between adjacent sections are set, and the wall thickness of the non-bearing area is reduced; for the key parts of the balloon, dynamic stiffness gradient printing control is realized; wherein the design rules of the balloon model in the balloon design need to consider the balloon length, according to the length of the blood vessel stenosis section + two end safety margins, the length of the blood vessel stenosis section is , the two end safety margins are , the balloon length is ; the balloon diameter, referring to the target blood vessel diameter, the proximal diameter of the stenosis section is , the distal diameter is , the balloon diameter is ; the bending compliance, the balloon wall thickness of the high curvature area is thinned or uses flexible material partition; bifurcation adaptation, the balloon at the complex bifurcation is designed as a double balloon or a side hole structure; calcification area strengthening, the spiral reinforcing rib or thickened wall thickness is added to the balloon surface corresponding to the calcification area; S4, the printing processing module is used for realizing material partition and density gradient control through 3D printing according to the optimized balloon structure, and manufacturing a patient-specific balloon. The image modeling module comprises the following steps:

2. The patient-specific 3D-printed model generation system for vascular intervention balloons of claim 1, wherein, CT or MRI images of the patient's blood vessels are acquired, U-Net neural network is adopted for automatic segmentation, a trained model is used for identifying the blood vessel boundary, and a binary mask of the blood vessel contour is output; wherein the blood vessel region is 1 and the background is 0; A skeletonization algorithm is used to extract the blood vessel center line, the curvature distribution of the center line is calculated and the high-curvature region is marked, and a blood vessel center line and a curvature distribution graph are generated; A CT image HU value is used to mark the calcification region, a threshold is set to identify the position and range of plaque calcification, and the spatial coordinates and distribution graph of the calcification region are generated; The bifurcation opening position and angle are identified through blood vessel connectivity analysis, and the included angle of the branch blood vessel and the main blood vessel is marked; The segmented blood vessel contour, center line, calcification mark and blood vessel branch are introduced into a reconstruction software to generate an STL format three-dimensional model with geometric feature annotation. The stress adjustment module comprises the following steps:

3. The patient-specific 3D-printed model generation system for vascular intervention balloons of claim 1, wherein, The diameter growth rate upper limit of the set curvature adaptation section and the pressure difference upper limit of the adjacent section are set, and the wall thickness of the non-load-bearing area is reduced, including: setting the diameter growth rate upper limit of the curvature adaptation section , the diameter growth rate , needs to meet ; set the pressure difference upper limit of the adjacent section , the pressure difference of the adjacent section ; analyze the non-load-bearing area of the balloon, according to the overall strength requirement of the balloon and the material characteristics, reduce the wall thickness of the non-load-bearing area, set the original wall thickness as , the wall thickness after reduction , wherein α is the reduction ratio.

4. The patient-specific 3D-printed model generation system for vascular intervention balloons of claim 1, wherein, The blood vessel is simplified into an isotropic elastic body according to the elastic modulus of the patient's blood vessel; The collection covers balloon size, shape, wall thickness distribution, and material. The material characteristic parameters and performance requirements under different working conditions are logically linked to form a rule base that covers many aspects of the balloon parameters; Determining the modulus of elasticity of the base material, adjusting the modulus of elasticity according to the actual application of the balloon material ; The stress distribution situation is determined by defining the simulated boundary condition and load application force; Finite element analysis software is used for stress distribution simulation calculation; The stress distribution results obtained through simulation calculation are analyzed to find out the stress concentration area and the unreasonable part of stress distribution. The dynamic stiffness gradient printing control for the key parts of the balloon comprises the following steps: the key parts of the balloon are determined, including the hinge joint, the curved inner wall and the curvature adaptation section; 3D printing technology is adopted for the key parts, the composition, density and layer thickness parameters of the printing material are controlled, the mathematical model between the material parameters and the stiffness is established according to the required stiffness of each part, and the corresponding material parameters are calculated according to the model to guide the printing process.

5. The patient-specific 3D-printed model generation system for vascular intervention balloons of claim 1, wherein, The intelligent balloon design work is carried out according to the upgraded blood vessel three-dimensional model, and the articulated structure adapted to the blood vessel is automatically segmented, which comprises the following steps:

6. The patient-specific 3D-printed model generation system for vascular intervention balloons of claim 4, wherein, The system further comprises: adjusting the elastic modulus of the base material according to the actually selected balloon material to obtain the elastic modulus of the actual balloon material ; fixing both ends of the balloon before simulation, simulating the constraint state of the balloon when the catheter is pushed; gradually applying the rated working pressure of the balloon to observe the stress distribution; setting the friction coefficient μ between the balloon and the inner wall of the blood vessel to simulate the interaction between the balloon and the inner wall of the blood vessel when the balloon is expanded; establishing a finite element model of the balloon and the blood vessel in the simulation software according to the geometric shape, size and material properties of the balloon and the blood vessel, and performing mesh division on the model; inputting boundary conditions, loads and material parameters into the simulation software and setting solving parameters; starting the simulation software to perform calculation and obtain the stress distribution results of the balloon under different working conditions.

7. The patient-specific 3D-printed model generation system for vascular intervention balloons of claim 1, wherein, The spiral center line of the blood vessel is accurately extracted from the CTA image of the patient, the minimum curvature radius of the blood vessel is calculated, the ECG signal and the DSA contrast data of the patient are synchronously collected, and a time-space four-dimensional model is generated based on the synchronous data; The three-dimensional model of the blood vessel bifurcation is reconstructed by using the CTA data, the vortex core coordinate, the vortex influence radius and the pulsating vortex migration characteristics of the bifurcation are calculated by combining the time-space four-dimensional model and the blood flow dynamics principle, the ECG signal and the ultrasonic Doppler data are synchronously collected, and the displacement vector and the migration angle of the blood vessel bifurcation in the systolic period are obtained; According to the overall shape of the blood vessel, the minimum curvature radius and the characteristics of the blood vessel bifurcation, the stress condition and the blood flow impact of the blood vessel are comprehensively considered, the number of micro grooves is calculated, and the layout of the micro grooves on the surface of the balloon is determined according to the spatial distribution rule of the blood vessel. ​ Combining the biological rhythm of blood vessels, the morphological changes of blood vessels and the micro groove layout, the hinge locking angle and the depth control law are determined, and the opening and closing logic is set so that the micro groove on the balloon surface can be dynamically adjusted according to the biological rhythm of the blood vessels.

8. The patient-specific 3D-printed model generation system of vascular intervention balloons of claim 7, wherein, The spiral center line comprises: An image segmentation algorithm is used to separate the blood vessel region from the background in the CTA image of the patient, and a skeleton-based algorithm is used to extract the spiral center line from the segmented blood vessel region; wherein the accuracy of the spiral center line is required to be within ±0.1mm.

Images