A method for controlling the diameter of a tapered intracranial sinus stent

Abstract

The present application relates to the technical field of intracranial venous sinus, in particular to a variable-diameter gradual change control method of intracranial venous sinus conical stent, comprising the following steps: establishing sinus cavity profile index based on intracranial venous sinus three-dimensional reconstruction grid and center line arc length position, screening the transition position of the pipe diameter and the partial circular area to form axial positioning nodes, setting the outer diameter of the stent ring unit, the mesh pitch and the circumferential opening, correcting the contact checking parameters through finite element simulation, and obtaining the stent forming instructions. After the three-dimensional reconstruction grid and the center line arc length position are matched, the sinus cavity profile index is formed, the transition position of the pipe diameter and the partial circular area jointly constrain the axial positioning nodes, the outer diameter of the stent ring unit, the axial pitch of the mesh, and the circumferential opening of the mesh are set along the gradual change path, the finite element contact checking introduces the sinus wall contact pressure, the wall gap and the stent wire strain, the connection rib inclination angle and the crown round corner radius are corrected accordingly, and the problems of wall gap, uneven load and wire deformation concentration are relieved.

Description

Technical Field

[0001] This invention relates to the field of intracranial venous sinus technology, and in particular to a method for gradually controlling the diameter of a tapered stent for intracranial venous sinuses. Background Technology

[0002] The field of intracranial venous sinus technology encompasses neurointerventional medicine, cerebral venous return pathways, diagnosis and treatment of venous sinus stenosis, design of endovascular implantable devices, and preoperative planning. This technical field primarily focuses on the anatomical structure, lumen morphology, blood flow pathways, lesion site identification, interventional device selection, and implantation path determination of intracranial venous sinuses. It is widely applied in neurosurgery, interventional radiology, endovascular therapeutic device development, and medical image-aided design. Please refer to... Figure 1 Traditional methods for controlling the gradual change in diameter of intracranial venous sinus conical stents refer to the methods used to set the diameter change pattern, axial transition shape, segmental structure distribution, and bending adaptation parameters of conical stents used in this location, taking into account the morphological differences in the intracranial venous sinus lumen along its length. These methods typically combine medical image reconstruction, lumen geometry measurement, stent parametric modeling, finite element analysis, mesh structure design, and processing path setting to plan the diameter gradient relationship and related structural parameters from the proximal to the distal end of the stent.

[0003] Traditional intracranial venous sinus tapered stent designs often rely on imaging measurements to set the proximal and distal diameter transitions. The direction of lumen curvature and non-circular cross-sections are often treated separately. The outer diameter of the stent ring unit and the mesh structure lack linkage verification with the sinus wall contact state. In actual operation, local wall gaps are prone to occur, the contact load is unevenly distributed, the stent wire deformation is concentrated, and the matching degree between the gradual segment forming command and the implantation channel is insufficient. Summary of the Invention

[0004] To address the technical problems existing in the prior art, this invention provides a method for gradually controlling the diameter of a tapered stent for intracranial venous sinuses. The technical solution is as follows: On the one hand, a method for gradually controlling the diameter of an intracranial venous sinus conical stent is provided, comprising the following steps: S1: Based on the intracranial venous sinus, obtain the three-dimensional reconstruction mesh and the position of the centerline arc length, calibrate the mesh cutting plane, trace the closure line of the lumen boundary, check the continuity of the cross-sectional contour, and obtain the sinus contour index. S2: Based on the sinus cavity contour index, call the cavity boundary closure line, organize the bending direction from the proximal end to the distal end, filter the cross-sectional area with a rounded shape, determine the overlap with the tube diameter transition position, and obtain the axial positioning node; S3: Based on the axial positioning node, obtain the spacing between adjacent nodes and the outer diameter of the support ring unit, arrange the support ring units, set the mesh pitch and circumferential opening, adjust the position of the transition node, and obtain the outer diameter gradient path; S4: Based on the outer diameter gradient path, call the support mesh unit and the cavity boundary, put in the finite element simulation calculation, obtain the contact pressure, wall-attached gap and support wire strain, correct the connecting rib angle and crown fillet, and obtain the contact verification parameters. S5: Based on the contact verification parameters, check the connection status of the outer diameter of the control node, organize the transition section of the tapered support mesh, adjust the connection sequence of the node outer diameter and the mesh pitch, and obtain the support forming command.

[0005] On the other hand, the sinus cavity contour index includes arc segment positioning marks, cavity wall closure marks, and cross-sectional normal references; the axial positioning nodes include inlet anchor points, bending inflection points, and radial transition points; the outer diameter gradient path includes ring diameter sequences, gradient section marks, and mesh unfolding sections; the contact verification parameters include wall load levels, wall adhesion status levels, and wire deformation levels; and the stent forming instructions include ring assembly codes, pitch arrangement codes, and coronal forming codes.

[0006] On the other hand, the steps for obtaining the sinus cavity contour index are as follows: S101: Based on the intracranial venous sinus, obtain the position of the arc length of the three-dimensional reconstruction mesh and the centerline, determine the matching status of the centerline direction and the shape of the lumen, adjust the corresponding area of ​​the arc length position in the mesh fragment, and obtain the arc length registration index. S102: Based on the arc length registration index, analyze the local direction of the center line, adjust the orientation of the mesh cutting surface, determine the intersection state of the cutting surface and the cross-sectional direction of the lumen, filter the beginning and end connected lumen boundaries, and obtain the closed-loop profile of the cross section. S103: Based on the closed-loop profile of the cross section, analyze the continuity between adjacent cross sections, determine the association status between the profile break part and the cross section normal reference, adjust the matching order of the arc segment positioning mark and the cavity wall closure mark, and obtain the sinus cavity profile index.

[0007] On the other hand, the steps for obtaining the axial positioning node are as follows: S201: Based on the sinus cavity contour index, analyze the arc segment positioning marks and the direction of the closed line, filter the cross-sectional contours that are continuously arranged from the proximal end to the distal end, calculate the displacement direction of the center of adjacent contours, determine the continuity of the center line turning in the cross-sectional sequence, and obtain the turning path sequence. S202: Based on the turning path sequence, analyze the unfolded shape of each cross section, calculate the difference between the extension range of the long axis and the extension range of the short axis, screen the sections with concentrated differences, adjust the position of the sections in the curved path, and obtain the semi-circular distribution sections. S203: Analyze the distribution range of the circular distribution section from the near end to the far end, compare the overlap between the distribution range and the pipe diameter transition position, screen the anchoring parts and section transition parts in the overlapping section, adjust the axial arrangement order of the nodes, and obtain the axial positioning nodes.

[0008] On the other hand, the specific steps for obtaining the outer diameter gradient path are as follows: S301: Based on the axial positioning nodes, analyze their arrangement from the proximal end to the distal end, calculate the constraint of the spacing between adjacent nodes on the arrangement range of the ring unit, determine the transition direction of the outer diameter of the support ring unit between each node, and obtain the ring diameter sequence. S302: Based on the ring diameter sequence, analyze the axial distribution state of the ring units, screen the expandable mesh sections between adjacent ring units, calculate the connection range between the axial pitch of the mesh and the circumferential opening of the mesh, adjust the arrangement order of the mesh between the rings, and obtain the mesh expansion sections. S303: Based on the mesh unfolding section, obtain the outer diameter change direction of adjacent ring units, compare the outer diameter change direction with the axial positioning node arrangement direction, determine the influence of the transition node insertion position on the continuous state of the tapered support diameter, adjust the axial position of the transition node, and obtain the outer diameter gradual change path.

[0009] On the other hand, the steps for obtaining the contact verification parameters are as follows: S401: Based on the outer diameter gradient path, analyze its unfolding direction within the intracranial venous sinus lumen boundary, screen the placement area of ​​the stent mesh unit in the curved tube segment, adjust the assembly posture of the outer edge of the ring unit close to the lumen boundary, determine the continuity of the mesh unit arrangement along the gradient path, and obtain the simulated assembly state. S402: Based on the simulated assembly state, calculate the sinus wall contact pressure distribution during the stent release process, compare the wall-attachment gap range between the outer surface of the stent and the lumen boundary, analyze the strain distribution of the stent wire in the bending section, determine the force continuity of the transition section mesh, and obtain the contact deformation state. S403: Based on the contact deformation state, screen the pressure concentration area and the gap concentration area, optimize the constraint state of the connecting rib tilt angle on the mesh unfolding direction, adjust the constraint state of the crown fillet radius on the bending shape of the support wire, determine the matching order of the wall load level and the wall adhesion state level, and obtain the contact verification parameters.

[0010] On the other hand, the steps for obtaining the stent forming command are as follows: S501: Based on the contact verification parameters, analyze the changes in the wall load level and the wall contact state level, screen the contact level transition segment in the outer diameter connection of the control node, determine whether the outer diameter transition of adjacent control nodes continues along the gradual path, adjust the outer diameter connection sequence, and obtain the outer diameter connection state. S502: Based on the outer diameter connection state, analyze the distribution sections in the tapered support gradient path, compare the mesh pitch continuity state between adjacent control nodes, filter the transition sections with concentrated pitch transitions, and adjust the arrangement order of mesh openings along the gradient path to obtain the mesh transition section. S503: Based on the mesh transition section, determine whether the arrangement direction of adjacent transition sections is consistent with the connection order of the node outer diameter, optimize the combination method of pitch arrangement code and crown forming code, adjust the arrangement order of ring assembly code, and obtain the bracket forming instruction.

[0011] On the other hand, the three-dimensional reconstruction grid refers to the three-dimensional surface structure reconstructed from intracranial venous sinus image data, representing the shape of the sinus wall and the spatial boundary of the lumen. The centerline arc length position refers to the position markings arranged from the proximal end to the distal end along the centerline of the intracranial venous sinus lumen, indicating the axial arrangement sequence of the stent.

[0012] On the other hand, the grid cutting surface refers to the cross section of the lumen set along the center line, which is used to cut out the outline of the intracranial venous sinus lumen. The bending direction refers to the change in the bending direction of the intracranial venous sinus center line in space, indicating the bending channel that the stent needs to adapt to.

[0013] On the other hand, the adjacent nodes refer to two nodes connected one after the other in the axial positioning nodes, which define the transition section between adjacent control positions of the support, and the support ring unit refers to the ring-shaped support structure of the tapered support arranged along the axial direction.

[0014] The beneficial effects of the technical solutions provided in the embodiments of the present invention include at least the following: After registering the three-dimensional reconstructed mesh with the centerline arc length position, a sinus cavity contour index is formed. The rounded region and the tube diameter transition position jointly constrain the axial positioning node. The outer diameter of the stent ring unit, the axial pitch of the mesh, and the circumferential opening of the mesh are set in a coordinated manner with the gradual change path of the outer diameter. Finite element contact verification introduces sinus wall contact pressure, wall gap and stent wire strain. The inclination angle of the connecting rib and the radius of the coronal corner are corrected accordingly to alleviate the problems of wall gap, uneven load and concentrated wire deformation. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of a tapered support. Figure 2 This is a flowchart of the main steps of the present invention; Figure 3 This is a flowchart of steps S1 of the present invention; Figure 4 This is a flowchart of steps S2 of the present invention; Figure 5 This is a flowchart of steps S3 of the present invention; Figure 6 This is a flowchart of step S4 of the present invention; Figure 7 This is a flowchart of step S5 of the present invention. Detailed Implementation

[0017] The technical solution of the present invention will now be described with reference to the accompanying drawings.

[0018] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0019] This invention provides a method for gradually controlling the diameter of a tapered stent for intracranial venous sinuses, such as... Figure 2 As shown, it includes the following steps: S1: Based on the intracranial venous sinus, obtain the three-dimensional reconstruction mesh and the arc length position of the center line, analyze the spatial registration relationship between the two, calibrate the mesh cutting plane according to the direction of the center line, trace the closure line of the lumen boundary along the cutting plane, and check the continuity of the cross-sectional contour to obtain the sinus cavity contour index. S2: Based on the sinus cavity contour index, call the cavity boundary closure line, organize the bending direction in order from proximal to distal, filter the off-circular area according to the difference between the major and minor axes of the cross section, determine the overlap between the off-circular area and the tube diameter transition position, and obtain the axial positioning node. S3: Based on the axial positioning node, obtain the spacing between adjacent nodes and the outer diameter of the support ring unit, arrange the ring units along the support axis, set the axial pitch of the mesh and the circumferential opening of the mesh, check the connection direction of the outer diameter of adjacent rings, adjust the insertion position of the transition node, and obtain the outer diameter gradient path. S4: Based on the outer diameter gradual path, call the stent mesh unit and the boundary of the intracranial venous sinus lumen, put in the finite element simulation calculation, obtain the sinus wall contact pressure, wall gap and stent wire strain, adjust the inclination angle of the connecting rib and the radius of the coronal fillet to obtain the contact check parameters; S5: Based on the contact verification parameters, analyze the connection status of the outer diameter of each control node, arrange the mesh transition section along the tapered support gradual path, check the arrangement direction of adjacent transition sections, adjust the connection sequence of node outer diameter and mesh pitch, and obtain the support forming command.

[0020] The sinus cavity contour index includes arc segment positioning marks, cavity wall closure marks, and cross-sectional normal references. Axial positioning nodes include inlet anchor points, bending inflection points, and radial transition points. The outer diameter gradient path includes ring diameter sequences, gradient section marks, and mesh unfolding sections. Contact verification parameters include wall load level, wall adhesion level, and wire deformation level. The stent forming instructions include ring assembly codes, pitch arrangement codes, and coronal forming codes.

[0021] In S1, the 3D reconstruction mesh refers to the 3D surface structure reconstructed from intracranial venous sinus image data, used to represent the shape of the sinus wall and the spatial boundary of the lumen; the centerline arc length position refers to the position markers arranged from proximal to distal along the centerline of the intracranial venous sinus lumen, used to indicate the axial arrangement sequence of the stents; the spatial registration relationship refers to the correspondence between the 3D reconstruction mesh and the centerline arc length position in spatial coordinates, used to confirm the matching of the centerline and the lumen orientation; the mesh section plane refers to the lumen section set along the centerline orientation, used to cut the contour of the intracranial venous sinus lumen; the closure line refers to the end-to-end connecting lumen boundary contour line formed on the mesh section plane; the continuity state refers to the positional connection between adjacent section contours, used to determine whether there is a break in the lumen contour when sampling along the centerline.

[0022] In S2, the curvature direction refers to the change in the curvature direction of the intracranial venous sinus centerline in space, used to indicate the curved channel that the stent needs to adapt to; the rounded region refers to the non-circular lumen region formed by the difference between the long axis and the short axis of the cross section; the diameter transition refers to the section where the lumen size changes along the proximal to distal direction; the overlapping state refers to the overlap of the rounded region and the diameter transition position in the axial position.

[0023] In S3, adjacent nodes refer to two nodes connected one after the other in the axial positioning nodes, used to define the transition section between adjacent control positions of the support; support ring unit refers to the ring-shaped support structure of the tapered support arranged along the axial direction; mesh axial pitch refers to the interval size of the support mesh along the axial direction; mesh circumferential opening refers to the opening width of the support mesh after it is unfolded along the circumferential direction; connection direction refers to the trend of the outer diameter of adjacent support ring units changing from the near end to the far end; insertion position refers to the position of the new transition node added between the original axial positioning nodes.

[0024] In S4, the stent mesh unit refers to a single mesh structure formed by stent wires, connecting ribs, and coronal structure; sinus wall contact pressure refers to the contact load acting on the intracranial venous sinus wall after stent release or deployment; wall-attachment gap refers to the distance area where the outer surface of the stent is not attached to the boundary of the intracranial venous sinus lumen; stent wire strain refers to the degree of deformation of the stent wire during bending, deployment, and wall-attachment; tilt angle refers to the angle of the connecting ribs relative to the axial or circumferential direction of the stent; and coronal fillet radius refers to the radius of the arc transition at the bend of the coronal part of the stent mesh.

[0025] In S5, a control node refers to an axial position point used to constrain the outer diameter of the support, the mesh pitch, or the structural transition; a gradual path refers to the axial route in which the outer diameter of the tapered support gradually changes from the proximal end to the distal end; a mesh transition section refers to the support section in which the mesh structure changes in pitch, opening, or outer diameter between adjacent control nodes; and the connection sequence refers to the axial arrangement order of the node outer diameter and the mesh pitch.

[0026] like Figure 3 As shown, the specific steps for obtaining the sinus cavity contour index are as follows: S101: Based on the intracranial venous sinus, obtain the position of the arc length of the three-dimensional reconstruction mesh and the centerline, determine the matching status of the centerline direction and the shape of the lumen, adjust the corresponding area of ​​the arc length position in the mesh fragment, and obtain the arc length registration index. Based on the image reconstruction results corresponding to the intracranial venous sinuses, the grid fragments, fragment vertices, fragment centers, fragment orientations, centerline sampling points, and arc length sorting markers of the sinus cavity surface are retrieved. Then, the centerline position is read point by point along the proximal to distal direction. The current arc length point is spatially correlated with the surrounding grid fragments. First, the distance from the arc length point to the fragment center is compared, then the spatial correspondence between the centerline direction and the fragment orientation is compared. Fragment regions matching the cross-section of the cavity where the current centerline point is located are selected as candidate regions. When multiple fragments satisfy the correspondence, the contour points of the surrounding wall are retrieved, and the position of the local cavity center enclosed by the contour points is compared with the current centerline point. The centerline point falls near the cavity center and along the line... Regions with continuous direction are retained, while regions where the centerline point deviates from the center of the cavity or falls outside the cavity wall are removed. When actually processing the curved segment from the transverse sinus to the sigmoid sinus, if the centerline point is close to one side of the cavity wall due to bending traction, the fragment assignment is rechecked in conjunction with the movement direction of adjacent arc length points, and the arc length point is moved from the edge fragment back to the fragment group corresponding to the middle of the cavity. For bifurcation locations, it is also necessary to check whether the same arc length point corresponds to multiple cavity fragments at the same time. If one group of fragments is continuous with the direction of the preceding and following arc length points, and another group of fragments suddenly turns, the fragment group with continuous direction is retained. After completing point-by-point correspondence, the arc length mark, fragment assignment, local direction, and cavity center offset status are written into the record in the same order to obtain the arc length registration index.

[0027] S102: Based on the arc length registration index, analyze the local direction of the center line, adjust the orientation of the mesh cutting plane, determine the intersection state of the cutting plane and the cross-sectional direction of the lumen, filter the beginning and end connected lumen boundaries, and obtain the closed-loop profile of the cross section. Based on the established arc length registration index, the centerline point, adjacent centerline points, registered fragment groups, and tube wall orientation corresponding to each arc length position are read. Then, the local orientation is determined based on the continuity direction between the current centerline point and adjacent centerline points, and this local orientation is used as a reference for adjusting the section orientation. In straight sinus segments, the section surface maintains a transverse direction perpendicular to the centerline orientation. In curved sinus segments, the section surface gradually rotates with the centerline's turning point to avoid the section surface obliquely penetrating the lumen. After completing the orientation adjustment, the grid fragments near the section surface are retrieved, and the crossing relationship between the fragment edge and the section surface is checked. When the fragment edge crosses from one side of the section surface to the other, the intersection position is recorded as a boundary candidate point. When the entire fragment remains on the same side of the section surface, it does not participate in the current section. Contour; When candidate points are distributed around the lumen circumference, connect adjacent candidate points in the order of arrangement around the lumen center, and check whether the beginning and end can be connected to form a loop; If multiple candidate boundaries appear, compare the positional relationship, enclosed range, and circumferential continuity of each boundary with the center line point, and retain the boundary that unfolds around the current lumen body and is connected end to end; For example, on the outer side of the sigmoid sinus bend, local fragments form a small free edge line. This edge line is deviated from the center line point and cannot form a complete cavity. It is removed during processing, and only the connected boundary around the sinus cavity body is retained; When there are small gaps in the local contour, continue to call the arrangement direction of adjacent boundary points and the adjacency relationship of fragments, and connect adjacent points on the same wall in circumferential order to obtain the cross-sectional closed-loop contour.

[0028] S103: Based on the closed-loop profile of the cross section, analyze the continuity between adjacent cross sections, determine the association status between the profile break point and the cross section normal reference, adjust the matching order of the arc segment positioning mark and the cavity wall closure mark, and obtain the sinus cavity profile index. Based on the continuous recording of the closed-loop profile of the cross section, the arc length mark, profile center, boundary point arrangement, closure state, cross section orientation, and correspondence between adjacent cross sections are retrieved for each cross section. Then, the continuity between adjacent cross sections is checked segment by segment along the near-end to far-end direction. First, it is compared whether the movement direction of the profile center follows the centerline; then, it is compared whether the change in the profile shape is a continuous transition; and finally, it is compared whether the circumferential arrangement of the boundary points remains in the same direction. If the center movement of adjacent cross sections is smooth, the shape change is continuous, and the boundary point arrangement has no reverse jump, then the adjacent relationship is recorded as a normal continuity. If a gap appears on one side of the profile, the circumferential position of the gap, the current cross section orientation, and the existence status of the boundary points on the same side of adjacent cross sections are checked. When the gap position is... When the cross-section changes synchronously with its orientation, it is classified as an abnormal cross-section orientation. When the gap is fixed in the same area of ​​the tube wall and adjacent cross-sections also have an unclosed state on the same side, it is classified as an abnormal cavity wall closure mark. In the actual area adjacent to transverse sinus stenosis, if a cross-section has a cluster of boundary points due to local flattening and the outline is broken on the short axis side, it is necessary to check whether the broken part is related to the tilt of the cutting plane. If the adjacent outlines can be connected sequentially after adjusting the cross-section orientation, the arc segment positioning mark is retained and the cavity wall closure mark is corrected. If the broken part is not related to the orientation, the cross-section is marked as closed and awaiting verification. After completing the segment-by-segment verification, the arc segment positioning mark, cavity wall closure mark, and cross-section normal reference are bound in the same arc length order to obtain the sinus cavity outline index.

[0029] like Figure 4 As shown, the specific steps for obtaining the axial positioning node are as follows: S201: Based on the sinus cavity contour index, analyze the arc segment positioning marks and the direction of the closed line, filter the cross-sectional contours that are continuously arranged from the proximal end to the distal end, calculate the displacement direction of the center of adjacent contours, determine the continuity of the center line turning in the cross-sectional sequence, and obtain the turning path sequence. For each arc segment, obtain its positioning marker, corresponding closed line, cross-section center, cross-section orientation, and cavity wall closure status. Then, arrange the cross-section records in order from proximal to distal, prioritizing records with abnormal closure status, misaligned arc segment positioning markers, or abrupt changes in cross-section orientation for verification. For continuous cross-sections, compare the movement direction of the current cross-section center relative to the previous cross-section center, and match this movement direction with the centerline direction recorded in the index. If the movement direction of the cross-section center extends to the same side as the preceding and following arc segments, the cross-section remains within the current path. If the cross-section center suddenly shifts to one side of the tube wall, continue checking for gaps, overlaps, or misconnections in the closed line of the cross-section. If the closed line arrangement is abnormal, correct the closed line order first, and then recheck the center movement direction. If the closed line is complete but the center movement direction is not aligned with the preceding and following cross-sections, place the cross-section between adjacent arc segments for re-comparison. In practice, the centerline of the transverse sinus often gradually turns downwards at the bend where it enters the sigmoid sinus. In this case, the center movement direction of adjacent sections should be a continuous turn, rather than a sudden reversal. If the center of a certain section shows an outward offset, the boundary points of that section are used to check whether the outer wall of the tube has shifted due to bending and stretching. Then, the section is assigned to the bend that is consistent with the forward and backward direction. After completing the continuous contour screening, center movement direction verification, and turn continuation verification, the positioning marks of the connected arc segments, the center movement direction of the sections, and the assignment of local turns are arranged in axial order to obtain the turn path sequence.

[0030] S202: Based on the turning path sequence, analyze the unfolded shape of each cross section profile, calculate the difference between the long axis extension range and the short axis extension range of the cross section, screen the sections with concentrated differences, adjust the position of the sections in the bending path, and obtain the slightly circular distribution sections. Retrieve the closed profile, center of the profile, direction of boundary points, and corresponding curved segment for each cross-section. Then, unfold the closed profile circumferentially and observe the extension of boundary points in relative directions, identifying the side with longer and shorter extensions. For each cross-section, first select the main extension direction that passes through the center of the cross-section and traverses the outermost boundary of the profile, then select the secondary extension direction that intersects the main extension direction, and compare the span difference between the two at the cavity boundary. When the main extension direction significantly exceeds the secondary extension direction, and this shape appears continuously in multiple adjacent cross-sections, the cross-section is classified as a candidate segment for rounded sections. When a single cross-section has a difference in extension but the cross-sections before and after it are not continuous, continue to check whether there are local gaps or misconnected boundary points in the closed line of the cross-section. If it is an abnormality in the profile connection, it is not considered a rounded segment. In practice, the sigmoid sinus curvature may exhibit a temporary elongated profile due to changes in the cutting angle. In such cases, it is necessary to determine whether the direction of extension continuously changes along the same side of the lumen boundary by considering the turning path. If the direction of extension smoothly changes with the curvature path, it is classified as a slightly rounded distribution within the curvature path. If the direction of extension does not have a fixed correspondence with the curvature path and only appears in a single cross-section, it is listed as a profile adjustment target. For the region adjacent to the transverse sinus stenosis, if the cross-section continuously exhibits a flattened and elongated shape on the same side, and this shape connects with the direction of the anterior and posterior arc segments, this continuous region is considered a segment with concentrated differences. Subsequently, its classification within the straight segment, turning segment, or transition segment is checked, and cross-sections mistakenly classified as adjacent curvature segments are rearranged into continuous segments to obtain a slightly rounded distribution segment.

[0031] S203: Analyze the distribution range of the off-circular distribution section from the near end to the far end, compare the overlap between the distribution range and the pipe diameter transition position, screen the anchoring parts and section transition parts in the overlapping section, adjust the axial arrangement order of the nodes, and obtain the axial positioning nodes. When analyzing the circular distribution sections, the starting and ending positions, outline extension direction, turning path, and adjacent pipe diameter change records of each circular region are read from the proximal end to the distal end. The circular regions are then compared with transitional positions where the pipe diameter changes from wide to narrow, from narrow to wide, or gradually. If the main part of the circular region falls within the pipe diameter change zone, the proximal boundary, distal boundary, and intermediate bend of that region are further examined. If the circular region only appears briefly in the pipe diameter stability zone, the closed outline is first checked to see if it is caused by the inclination of the cutting plane before deciding whether to retain it as a node reference. For overlapping areas, positions with complete closed outlines, smooth centerline direction, and no obvious misalignment of the lumen boundaries are first selected from the proximal side as inlet anchoring candidates. Then, bend turning candidates are searched at the positions where the bend direction change is most concentrated. Subsequently, radial segment replacement candidates are searched at the positions where the pipe diameter change trend changes and the circular shape begins to weaken or strengthen. In practice, the transition from the transverse sinus to the sigmoid sinus may involve both deepening of the bend and narrowing of the tube diameter. If the inlet profile is intact and the degree of roundness is not yet concentrated, this location is suitable as the inlet anchor point. If the direction of the middle profile clearly changes with the centerline, this location is classified as the bend inflection point. If the distal profile gradually returns from a flat and elongated shape to a near-round shape, and the change in tube diameter tends to stabilize, this location is classified as the radial transition point. After screening the candidate sites, the nodes are rearranged in axial order, and duplicate candidate nodes are merged. Nodes that are discontinuous with the turning path are moved to the verification sequence to obtain the axial positioning nodes.

[0032] like Figure 5 As shown, the specific steps for obtaining the outer diameter gradient path are as follows: S301: Based on the axial positioning nodes, analyze their arrangement from the proximal end to the distal end, calculate the constraint of the spacing between adjacent nodes on the arrangement range of the ring unit, determine the transition direction of the outer diameter of the support ring unit between each node, and obtain the ring diameter sequence. The system retrieves the sequential relationship between the inlet anchor point, bending turning point, and radial segment change point on the same centerline. Simultaneously, it calls the preset support ring unit structural parameters, connecting rib arrangement parameters, and mesh unfolding parameters, and reads the corresponding cavity profile, local pipe diameter status, bending assignment, and closure mark for each node. Then, it checks the node arrangement for continuity along the proximal to distal direction. If a node moves in the opposite direction to the cavity center movement of the preceding and following nodes, it returns to the turning path sequence to check its bending assignment. If a node falls on a position where the profile is broken or closed and needs to be checked, it is first moved to the position to be adjusted, and then replaced by an adjacent closed and complete section for positioning. The interval between adjacent nodes is not directly treated as a fixed length, but is compared with the support ring unit's own occupancy, the unfolding allowance of the connecting ribs between adjacent rings, and the transition space required for the bending section to adhere to the wall. When the space between nodes can accommodate a continuous ring array, the starting ring outer diameter is set according to the actual state of the proximal cavity being wider or narrower, and the ending ring outer diameter is set according to the cavity profile corresponding to the distal node. When the space between nodes is short and the bending is concentrated, the diameter abrupt changes in the middle ring array are reduced, and the transition changes are dispersed to the outside of adjacent nodes. In actual implementation, if the outline of the inlet anchor point is relatively round, the outline becomes flatter at the bend and turning point, and the lumen continues to narrow at the radial transition point, then the outer diameter of the ring unit is arranged in the order that the inlet position is closer to the proximal lumen, the turning point gradually shrinks, and the transition point connects to the distal lumen; if there is a local reverse transition from narrow to wide, then the direction of change of the ring outer diameter is rearranged according to the unfolding state of the lumen in that section, forming a ring diameter sequence consistent with the node sequence.

[0033] S302: Based on the ring diameter sequence, analyze the axial distribution state of the ring unit, screen the expandable mesh sections between adjacent ring units, calculate the connection range between the axial pitch of the mesh and the circumferential opening of the mesh, adjust the arrangement order of the mesh between the rings, and obtain the mesh expansion section. The axial position, outer diameter, connection relationship between adjacent rings, bend segment assignment, and node control mark of each ring unit are read. Then, the presence of expandable mesh space between ring units is checked along the support axis. If the outer diameter change of adjacent rings is smooth and there is sufficient expansion allowance for connecting ribs between rings, the area between rings is listed as a candidate expandable section. If the outer diameter change of adjacent rings is sudden or the corresponding lumen profile is closed and needs verification, the area between rings is not included in the expansion section. When organizing candidate sections, first compare whether the axial spacing of adjacent ring units can withstand mesh stretching, and then compare whether the difference in outer diameter of adjacent rings will cause circumferential opening deviation. If the axial spacing is too tight, the mesh pitch is arranged more compactly, and the inclination direction of the connecting ribs is kept consistent with the bend path. If the circumferential opening is unevenly expanded at the outer diameter change point, the corresponding position of the mesh between adjacent rings is adjusted so that the crown and connecting ribs on the same side are continuously distributed along the lumen profile. In practice, if the stent enters the curved position of the sigmoid sinus from a wider position in the transverse sinus, with a larger outer diameter of the proximal ring and a gradually decreasing outer diameter of the distal ring, then when the same row of meshes unfolds, it is necessary to avoid one side having an excessively large opening and the other side having an excessively dense opening. In this case, the meshes on the outer curved side should be aligned with the direction of curvature first, and then the meshes on the inner curved side should be aligned with the direction of contraction. If there is an irregularity in the interlacing of adjacent meshes, the axial arrangement order of the local meshes should be exchanged, and the coronal continuation direction should be rechecked to obtain the mesh unfolding section.

[0034] S303: Based on the mesh unfolding section, obtain the outer diameter change direction of adjacent ring units, compare the outer diameter change direction with the axial positioning node arrangement direction, determine the influence of the transition node insertion position on the continuous state of the tapered support diameter, adjust the axial position of the transition node, and obtain the outer diameter gradual change path. Retrieve the outer diameter change direction, node arrangement direction, mesh pitch continuity, and circumferential opening arrangement of the adjacent ring elements corresponding to each unfolded section; then, check whether the outer diameter gradually decreases, gradually increases, or changes direction at local bends along the proximal to distal direction, and compare this change direction with the sequence of the entrance anchor point, bend inflection point, and radial transition point. If the outer diameter change direction is consistent with the node arrangement direction, and the mesh pitch is smoothly connected between adjacent sections, the original node position is retained; if there is a sudden jump in the outer diameter between adjacent rings, or the mesh openings are reversed before and after a certain control node, then find a suitable transition position near that node. The selection of transition positions does not solely depend on pipe diameter changes; it also requires simultaneous verification of the completeness of the contour closure, the smoothness of the centerline turning, the orientation of the connecting ribs of adjacent ring units, and the arrangement of the crown. When a certain point has a complete contour, the pipe diameter change begins to slow down, and the mesh unfolding direction remains continuous, that point can be used as the insertion position for the transition node. When a certain point is where the contour is broken, the lumen is most flattened, or there is a sharp bend, the transition node is not directly inserted; instead, the node is moved forward or backward to the adjacent connecting section. In actual implementation, if the rounded distribution section overlaps with the pipe diameter contraction section, the original radial transition point may cause the outer diameter of the ring to change too rapidly on the outside of the bend. In this case, the transition node is moved to the side where the roundness weakens, and the mesh pitch arrangement before and after that point is adjusted simultaneously. If the distal lumen gradually becomes rounded, the transition node extends along the outer diameter gradual change direction to the position where the rounded contour begins to stabilize, and the ring diameter sequence, transition node position, gradual change section mark, and mesh unfolding section are associated and recorded to obtain the outer diameter gradual change path.

[0035] like Figure 6 As shown, the specific steps for obtaining the contact verification parameters are as follows: S401: Based on the gradual change path of the outer diameter, analyze its unfolding direction within the boundary of the intracranial venous sinus lumen, screen the placement area of ​​the stent mesh unit in the curved section, adjust the assembly posture of the outer edge of the ring unit close to the lumen boundary, determine the continuity of the arrangement of the mesh unit along the gradual change path, and obtain the simulated assembly state. Retrieve the ring diameter sequence, mesh unfolding sections, transition node positions, and corresponding sinus cavity boundary contours. Then, place the stent rings into the lumen space along the centerline, checking the relative positions between the outer edges of the ring units and the lumen boundaries segment by segment. For straight segments, the outer edges of the ring units correspond to the lumen walls according to the circumferential sequence of the cross-sectional contours; for curved segments, the outer edges of the ring units need to be rearranged in conjunction with the inner, outer, and rounded distribution directions of the curve. If a mesh unit falls on the outer side of the curve, check whether its connecting ribs unfold along the stent axis; if a mesh unit falls on the inner side of the curve, check whether its coronal portion is excessively close or staggered. Subsequently, read the connection relationship between each mesh unit and adjacent ring units, prioritizing mesh units located near rounded sections, diameter transition sections, and radial transition points; if a mesh unit crosses adjacent outer diameter change sections, continue to check whether its circumferential openings connect with the preceding and following meshes. In actual implementation, when the stent enters the curved area of ​​the sigmoid sinus from the relatively rounded area of ​​the transverse sinus, the proximal ring can be placed along the rounded cavity wall. After entering the curved section, the unfolding direction of the mesh on the outer curved side needs to correspond to the turning direction of the lumen, and the mesh on the inner curved side needs to be kept in an arrangement that does not overlap with each other. If the outer edge of the ring unit deviates significantly from the cavity wall at a certain point, the rotation attitude and axial front-back position of the ring center line are adjusted, and the arrangement relationship of the adjacent meshes is rechecked to finally form a simulated assembly state.

[0036] S402: Based on the simulated assembly state, calculate the sinus wall contact pressure distribution during the stent release process, compare the wall-attachment gap range between the outer surface of the stent and the lumen boundary, analyze the strain distribution of the stent wire in the bending section, determine the force continuity of the mesh in the transition section, and obtain the contact deformation state. Based on the simulated assembly state, the nodes on the outer surface of the stent, the sinus wall partitions, the outer edge of the ring unit, the position of the connecting ribs, the position of the coronal portion, and the placement of the mesh units are obtained. Then, the process of the stent expanding from a compressed state into the lumen is simulated, and the positions where the outer surface of the stent contacts the boundary of the sinus cavity are recorded step by step. For the handling of contact pressure, instead of single-point judgment, it is organized separately according to the proximal anchoring zone, the bending transition zone, the radial transition zone, and the distal connection zone. If the contact points are evenly distributed and the directions of adjacent contact points are consistent within a certain area, it is recorded as a stable contact state; if the contact points are concentrated near one side of the coronal portion or one side of the connecting ribs, it is recorded as a concentrated contact state; if there is a continuous non-contact space between the outer edge of the stent and the cavity wall, it is recorded as a gap concentration state. Subsequently, the fit between the outer surface of the stent and the boundary of the lumen is compared, focusing on whether there is excessive mesh contact on the inner side of the bend and whether there is insufficient expansion on the outer side of the bend. Then, the deformation records of the stent wires during bending, expansion, and wall adhesion are read to check whether the force direction of adjacent meshes within the same transition section is continuous. In practice, if the outer diameter gradient path contracts too quickly within the rounded tube cavity, a continuous gap may form on the outer side of the bend, while contact concentration may occur on the inner crown. In this case, the area is marked as a contact deformation state requiring adjustment. After completing the pressure distribution sorting, gap range verification, and wire deformation arrangement check, the contact deformation state is obtained.

[0037] S403: Based on the contact deformation state, screen the pressure concentration area and the gap concentration area, optimize the constraint state of the connecting rib tilt angle on the mesh unfolding direction, adjust the constraint state of the crown fillet radius on the bending shape of the support wire, determine the matching order of the wall load level and the wall adhesion state level, and obtain the contact verification parameters. Acquire information on the contact status, wall gap status, scaffold wire bending status, connecting rib tilt direction, and coronal bending morphology of each segment. Then, examine the distribution relationship between pressure concentration points and gap concentration points segment by segment from proximal to distal. If pressure concentration occurs near the inner side of the coronal section of the bend, check whether adjacent connecting ribs simultaneously deflect to that side. If gap concentration occurs near the outer mesh of the bend, check whether the mesh unfolding direction at that location does not follow the outer edge of the lumen. Subsequently, adjust the connecting rib tilt angle at the structural level. During adjustment, do not directly change the entire ring array; instead, first select the affected adjacent meshes and change the connecting ribs from an excessively inward-biased state to a state that unfolds in a gradually changing axial direction. Then, verify whether the coronal section still smoothly connects with the adjacent ring unit after adjustment. For adjusting the coronal corner radius, first check whether a sharp turn or local compression is formed at the bend, then change the coronal bend from a tight state to a smooth state, and simultaneously check whether the scaffold wire's direction between adjacent meshes is continuous. In practice, when the eccentric distribution section overlaps with the pipe diameter transition section, if the inner contact is concentrated while the outer side has a gap, the inclination direction of the connecting ribs should be adjusted first, then the crown bending shape should be corrected, and then the corresponding order between the wall load level, the wall contact state level, and the wire deformation level should be rearranged. After checking each section, the wall load level, the wall contact state level, and the wire deformation level should be bound as contact verification parameters.

[0038] like Figure 7 As shown, the specific steps for obtaining the stent forming command are as follows: S501: Based on the contact verification parameters, analyze the changes in the wall load level and the wall-attachment state level, screen the contact level transition segments in the outer diameter connection of the control nodes, determine whether the outer diameter transition of adjacent control nodes continues along the gradual path, adjust the outer diameter connection sequence, and obtain the outer diameter connection state. Retrieve the wall load level, wall adhesion level, wire deformation level, ring outer diameter status, and the corresponding transition section for each control node; then read the locations where the level changes along the support axis, marking the locations where the load level changes from stable to concentrated, the locations where the wall adhesion changes from close to gapped, and the locations where the wire deformation changes from continuous to tight bending as contact level transition locations. For these transition locations, continue to check whether they are located near the inlet anchor point, bending inflection point, radial transition point, or transition node; if the transition location coincides with the outer diameter change location, retrieve the arrangement relationship of the ring outer diameter before and after that location to check whether the outer diameter changes continuously along the transition path; if the transition location deviates from the outer diameter transition location, continue to compare the cavity wall profile and mesh unfolding direction of adjacent control nodes to check whether the deviation is caused by local bending, off-circular profile, or crown pressure. During the pre-forming verification, if a section of the tube gradually transitions from a round shape to a slightly flatter shape, while the outer diameter of the support ring remains in its original connection sequence, the wall-hugging state may transition into a gap state on the outer bend side. In this case, this section is first classified as a contact level transition segment, and then the outer diameter connection relationship corresponding to this segment is rearranged towards the transition node. If there is a sudden change in outer diameter between adjacent control nodes, the ring sequence before and after the change is reorganized to ensure that the outer diameter changes between the inlet anchor point, the bend inflection point, and the radial transition point are continuously recorded. After completing the corresponding organization of control nodes, contact levels, and outer diameter changes, an outer diameter connection state is formed.

[0039] S502: Based on the outer diameter connection state, analyze the distribution sections in the tapered support gradient path, compare the mesh pitch continuity state between adjacent control nodes, filter the transition sections with concentrated pitch transitions, and adjust the arrangement order of mesh openings along the gradient path to obtain the mesh transition section. Retrieve the entry anchoring zone, bending transition zone, radial segment change zone, and distal connection zone from the tapered support's gradual transition path, and read the outer diameter of the ring array, mesh pitch, circumferential opening, connecting rib orientation, and crown connection status within each zone. Then, sequentially unfold the mesh pitch between adjacent control nodes axially, observing the positions where the pitch changes from compact to extended or vice versa, and compare these positions with the outer diameter connection status. If the pitch change position coincides with the outer diameter change position, retain the original mesh arrangement; if the pitch change precedes or lags the outer diameter change, continue checking whether the mesh opening shows circumferential skew, whether the connecting ribs show reverse traction, and whether the crowns are staggered or close together. For areas with concentrated pitch transitions, first read the ring assembly relationship on both sides of the area, then organize the mesh openings located on the inner side of the bend, the outer side of the bend, and the direction of the major axis of the eccentricity. The mesh openings on the inner side of the bend are arranged in a closed state, the mesh openings on the outer side of the bend are arranged in an open state, and the mesh openings in the direction of the major axis of the eccentricity are arranged according to the direction of contour extension. In the actual tapered support transition section, if the outer diameter gradually connects from the wide opening at the near end to the narrow opening at the far end, and the mesh pitch suddenly concentrates in the middle, then first mark this area as the concentrated pitch transition section, and then adjust the front and back arrangement of the mesh openings so that the pitch change corresponds to the outer diameter connection state; after completing the organization of the mesh pitch, circumferential opening, and control node relationship, a mesh transition section is formed.

[0040] S503: Based on the mesh transition section, determine whether the arrangement direction of adjacent transition sections is consistent with the connection order of the node outer diameter, optimize the combination of pitch arrangement code and crown forming code, adjust the arrangement order of ring assembly code, and obtain the stent forming command. After completing the verification of adjacent transition section direction, node outer diameter connection order, and code combination, combine the ring assembly code, pitch arrangement code, and crown forming code to obtain the stent forming command; Obtain the axial alignment direction, outer diameter connection status, pitch alignment status, crown bending status, ring assembly relationship, and node control marks for each transition segment. Then, check the alignment direction between adjacent transition segments along the gradient path. If the preceding transition segment points towards radial contraction while the following transition segment remains wide open, list the two segments as positions requiring adjustment of alignment direction. If the transition segment alignment direction matches the node outer diameter connection sequence, continue verifying the combination relationship between the pitch alignment code and the crown forming code. For the pitch alignment code, first sort according to the expansion, contraction, and segment transition states of the mesh from the proximal end to the distal end. For the crown forming code, first sort according to the crown roundness, bending direction, and connection relationship with the connecting ribs. Then, match the two within the same transition segment. If the pitch is in a contracted state while the crown remains in an expanded state, adjust the crown code assignment. If the crown bending direction is opposite to the connecting rib inclination direction, move the mesh transition segment into the recombination sequence. During actual forming, if the transition section after the bending inflection point has already entered the outer diameter contraction arrangement, but the ring assembly code is still output in the near-end wide opening sequence, it will cause the assembly sequence to be inconsistent with the gradual path. In this case, first adjust the front and back arrangement of the ring assembly code, and then simultaneously correct the combination order of the pitch arrangement code and the crown forming code. After completing the direction verification of adjacent transition sections, the connection order of node outer diameters, and the code combination sorting, the bracket forming command is obtained.

[0041] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for gradually controlling the diameter of a conical stent for intracranial venous sinuses, characterized in that, The method includes: S1: Based on the intracranial venous sinus, obtain the three-dimensional reconstruction mesh and the position of the centerline arc length, calibrate the mesh cutting plane, trace the closure line of the lumen boundary, check the continuity of the cross-sectional contour, and obtain the sinus contour index. S2: Based on the sinus cavity contour index, call the cavity boundary closure line, organize the bending direction from the proximal end to the distal end, filter the cross-sectional area with a rounded shape, determine the overlap with the tube diameter transition position, and obtain the axial positioning node; S3: Based on the axial positioning node, obtain the spacing between adjacent nodes and the outer diameter of the support ring unit, arrange the support ring units, set the mesh pitch and circumferential opening, adjust the position of the transition node, and obtain the outer diameter gradient path; S4: Based on the outer diameter gradient path, call the support mesh unit and the cavity boundary, put in the finite element simulation calculation, obtain the contact pressure, wall-attached gap and support wire strain, correct the connecting rib angle and crown fillet, and obtain the contact verification parameters. S5: Based on the contact verification parameters, check the connection status of the outer diameter of the control node, organize the transition section of the tapered support mesh, adjust the connection sequence of the node outer diameter and the mesh pitch, and obtain the support forming command.

2. The method for gradually controlling the diameter of the intracranial venous sinus conical stent according to claim 1, characterized in that, The sinus cavity contour index includes arc segment positioning marks, cavity wall closure marks, and cross-sectional normal references. The axial positioning nodes include inlet anchor points, bending inflection points, and radial transition points. The outer diameter gradient path includes a ring diameter sequence, gradient section marks, and mesh unfolding sections. The contact verification parameters include wall load level, wall adhesion level, and wire deformation level. The stent forming instructions include ring assembly codes, pitch arrangement codes, and coronal forming codes.

3. The method for gradually controlling the diameter of the intracranial venous sinus conical stent according to claim 1, characterized in that, The specific steps for obtaining the sinus cavity contour index are as follows: S101: Based on the intracranial venous sinus, obtain the position of the arc length of the three-dimensional reconstruction mesh and the centerline, determine the matching status of the centerline direction and the shape of the lumen, adjust the corresponding area of ​​the arc length position in the mesh fragment, and obtain the arc length registration index. S102: Based on the arc length registration index, analyze the local direction of the center line, adjust the orientation of the mesh cutting surface, determine the intersection state of the cutting surface and the cross-sectional direction of the lumen, filter the beginning and end connected lumen boundaries, and obtain the closed-loop profile of the cross section. S103: Based on the closed-loop profile of the cross section, analyze the continuity between adjacent cross sections, determine the association status between the profile break part and the cross section normal reference, adjust the matching order of the arc segment positioning mark and the cavity wall closure mark, and obtain the sinus cavity profile index.

4. The method for gradually controlling the diameter of the intracranial venous sinus conical stent according to claim 1, characterized in that, The specific steps for obtaining the axial positioning node are as follows: S201: Based on the sinus cavity contour index, analyze the arc segment positioning marks and the direction of the closed line, filter the cross-sectional contours that are continuously arranged from the proximal end to the distal end, calculate the displacement direction of the center of adjacent contours, determine the continuity of the center line turning in the cross-sectional sequence, and obtain the turning path sequence. S202: Based on the turning path sequence, analyze the unfolded shape of each cross section, calculate the difference between the extension range of the long axis and the extension range of the short axis, screen the sections with concentrated differences, adjust the position of the sections in the curved path, and obtain the semi-circular distribution sections. S203: Analyze the distribution range of the circular distribution section from the near end to the far end, compare the overlap between the distribution range and the pipe diameter transition position, screen the anchoring parts and section transition parts in the overlapping section, adjust the node arrangement order along the axial direction, and obtain the axial positioning node.

5. The method for gradually controlling the diameter of the intracranial venous sinus conical stent according to claim 1, characterized in that, The specific steps for obtaining the outer diameter gradient path are as follows: S301: Based on the axial positioning nodes, analyze their arrangement from the proximal end to the distal end, calculate the constraint of the spacing between adjacent nodes on the arrangement range of the ring unit, determine the transition direction of the outer diameter of the support ring unit between each node, and obtain the ring diameter sequence. S302: Based on the ring diameter sequence, analyze the axial distribution state of the ring units, screen the expandable mesh sections between adjacent ring units, calculate the connection range between the axial pitch of the mesh and the circumferential opening of the mesh, adjust the arrangement order of the mesh between the rings, and obtain the mesh expansion sections. S303: Based on the mesh unfolding section, obtain the outer diameter change direction of adjacent ring units, compare the outer diameter change direction with the axial positioning node arrangement direction, determine the influence of the transition node insertion position on the continuous state of the tapered support diameter, adjust the axial position of the transition node, and obtain the outer diameter gradual change path.

6. The method for gradually controlling the diameter of the intracranial venous sinus conical stent according to claim 1, characterized in that, The specific steps for obtaining the contact verification parameters are as follows: S401: Based on the outer diameter gradient path, analyze its unfolding direction within the intracranial venous sinus lumen boundary, screen the placement area of ​​the stent mesh unit in the curved tube segment, adjust the assembly posture of the outer edge of the ring unit close to the lumen boundary, determine the continuity of the mesh unit arrangement along the gradient path, and obtain the simulated assembly state. S402: Based on the simulated assembly state, calculate the sinus wall contact pressure distribution during the stent release process, compare the wall-attachment gap range between the outer surface of the stent and the lumen boundary, analyze the strain distribution of the stent wire in the bending section, determine the force continuity of the transition section mesh, and obtain the contact deformation state. S403: Based on the contact deformation state, screen the pressure concentration area and the gap concentration area, optimize the constraint state of the connecting rib tilt angle on the mesh unfolding direction, adjust the constraint state of the crown fillet radius on the bending shape of the support wire, determine the matching order of the wall load level and the wall adhesion state level, and obtain the contact verification parameters.

7. The method for gradually controlling the diameter of the intracranial venous sinus conical stent according to claim 1, characterized in that, The specific steps for obtaining the stent forming command are as follows: S501: Based on the contact verification parameters, analyze the changes in the wall load level and the wall contact state level, screen the contact level transition segment in the outer diameter connection of the control node, determine whether the outer diameter transition of adjacent control nodes continues along the gradual path, adjust the outer diameter connection sequence, and obtain the outer diameter connection state. S502: Based on the outer diameter connection state, analyze the distribution sections in the tapered support gradient path, compare the mesh pitch continuity state between adjacent control nodes, filter the transition sections with concentrated pitch transitions, and adjust the arrangement order of mesh openings along the gradient path to obtain the mesh transition section. S503: Based on the mesh transition section, determine whether the arrangement direction of adjacent transition sections is consistent with the connection order of the node outer diameter, optimize the combination method of pitch arrangement code and crown forming code, adjust the arrangement order of ring assembly code, and obtain the bracket forming instruction.

8. The method for gradually controlling the diameter of the intracranial venous sinus conical stent according to claim 1, characterized in that, The three-dimensional reconstruction mesh refers to the three-dimensional surface structure reconstructed from intracranial venous sinus image data, representing the shape of the sinus wall and the spatial boundary of the lumen. The centerline arc length position refers to the position markings arranged from the proximal end to the distal end along the centerline of the intracranial venous sinus lumen, indicating the axial arrangement sequence of the stent.

9. The method for gradually controlling the diameter of the intracranial venous sinus conical stent according to claim 1, characterized in that, The grid cutting surface refers to the cross-section of the lumen set along the centerline, used to cut out the outline of the intracranial venous sinus lumen. The curvature refers to the change in the curvature direction of the intracranial venous sinus centerline in space, indicating the curvature channel that the stent needs to adapt to.

10. The method for gradually controlling the diameter of the intracranial venous sinus conical stent according to claim 1, characterized in that, The adjacent nodes refer to two nodes connected one after the other in the axial positioning nodes, which define the transition section between adjacent control positions of the support. The support ring unit refers to the ring-shaped support structure arranged along the axial direction of the tapered support.

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