KR102642437B1 - Method for vascular deformation simulation by catheter insertion in vascular intervention - Google Patents

Abstract

The present invention relates to a method for simulating blood vessel deformation by catheter insertion in vascular interventional procedures. The method includes the steps of: (a) generating a 3D blood vessel model of the patient from a medical image of the patient, and obtaining a blood vessel center line model having a plurality of blood vessel center points extracted from the 3D blood vessel model; (b) obtaining the coordinates of the center point of the vascular catheter and performing initial registration of converting the vascular center line model and the coordinates of the center point of the vascular catheter into coordinate values of a reference coordinate system; (c) setting an initial value for deforming the blood vessel center line model and dividing the blood vessel center line model into a plurality of unit elements; and (d) the unit by considering the elastic potential energy stored in the unit element due to deformation of adjacent elements adjacent to the unit element so that the corresponding point of the blood vessel center line model can be matched to the center point of the catheter inserted into the blood vessel. It may include calculating the deformation of the element.

Description

Method for simulating blood vessel deformation by catheter insertion in vascular intervention procedures {METHOD FOR VASCULAR DEFORMATION SIMULATION BY CATHETER INSERTION IN VASCULAR INTERVENTION}

The present invention relates to a method of simulating in real time the deformation of blood vessels accompanying the insertion of a vascular catheter equipped with a three-dimensional shape sensor into a blood vessel in vascular interventional procedures.

Vascular intervention is a procedure that treats lesions by inserting surgical tools such as catheters or guide wires into blood vessels. Blood vessels can be visualized with a 2D image acquisition device through contrast agent injection, and the operator must selectively insert each branch of the blood vessel so that the tip of the surgical tool can be accurately positioned on the lesion.

It is difficult to insert a surgical tool by deducing the three-dimensional structure of a blood vessel using only a two-dimensional image, and continuously using contrast agents and imaging equipment to check the path of the surgical tool to the lesion increases the problem of radiation exposure for the patient and operator. cause

Recently, technology is being developed to generate 3D information about blood vessels based on medical images taken before the procedure and match this to 2D images taken during the procedure. However, because visualization of blood vessels during the procedure relies on images acquired with 2D imaging equipment, the problem of radiation exposure to the operator and patient is inevitable as long as radiation-based 2D acquisition equipment is used.

According to Non-Patent Document 1 below, in order to solve this problem, a study was conducted to match the 3D information of blood vessels obtained before the procedure with the 3D center line information of the surgical tool equipped with a shape sensor and estimate the position of the tip of the surgical tool. . Before the procedure, the blood vessels injected with contrast agent are tomographically scanned using equipment such as CT or MRI, and the 3D model and center line of the blood vessels are extracted using the intensity of the tomographic image. During the procedure, ultrasound images are used to compensate for the deformation of blood vessels that occur due to differences from the images obtained before the procedure, such as the patient's breathing or movement. The position of the tip of the surgical tool equipped with a shape sensor is estimated by matching the curve of the center line of the shape sensor acquired during the procedure with the center line of the compensated 3D blood vessel model.

However, because the surgical tool has bending rigidity, it applies force to the inner wall of the blood vessel when inserted into the blood vessel, causing deformation of the blood vessel. This deformation may vary depending on the patient's anatomy, including the unique physical properties of the blood vessel (elastic modulus, density, radius, etc.) and the connection point between the blood vessel and bone. However, technology that matches the patient's three-dimensional vascular structure using shape sensors and ultrasound images does not take into account the deformation of blood vessels due to insertion of surgical tools. It is known from numerous literature that the stiffness of surgical tools causes deformation of blood vessels during the procedure, which affects registration accuracy.

Therefore, a method is needed to simulate in real time the deformation of a blood vessel that occurs when a surgical tool is inserted into a blood vessel based on the physical properties and geometric structure of the blood vessel.

Parent, F., Gerard, M., Monet, F., Loranger, S., Soulez, G., Kashyap, R., and Kadoury, S., “Intra-Arterial Image Guidance With Optical Frequency Domain Reflectometry Shape Sensing” ,IEEE Transactions on Medical Imaging 2018, vol. 38, no. 2, pp. 482?492.

The purpose of the present invention is to provide a method for simulating blood vessel deformation by catheter insertion in vascular interventional procedures to simulate in real time the deformation of blood vessels accompanying the insertion of a vascular catheter equipped with a three-dimensional shape sensor into a blood vessel and to guide catheter insertion. In providing.

The present invention to solve the above problems relates to a method for simulating blood vessel deformation by catheter insertion in vascular interventional procedures. The method includes the steps of: (a) generating a 3D blood vessel model of the patient from a medical image of the patient, and obtaining a blood vessel center line model having a plurality of blood vessel center points extracted from the 3D blood vessel model; (b) obtaining the coordinates of the center point of the vascular catheter and performing initial registration of converting the vascular center line model and the coordinates of the center point of the vascular catheter into coordinate values of a reference coordinate system; (c) setting an initial value for deforming the blood vessel center line model and dividing the blood vessel center line model into a plurality of unit elements; and (d) the unit by considering the elastic potential energy stored in the unit element due to deformation of adjacent elements adjacent to the unit element so that the corresponding point of the blood vessel center line model can be matched to the center point of the catheter inserted into the blood vessel. It may include calculating the deformation of the element.

According to an embodiment of the present invention, step (a) includes: (a-1) extracting the three-dimensional blood vessel model from the medical image of the patient; and (a-2) constructing the blood vessel center line model by sampling the center line of the extracted three-dimensional blood vessel model at regular intervals.

According to an embodiment of the present invention, the vascular catheter is equipped with a shape sensor, and step (b) includes: (b-1) acquiring a reference coordinate system using a marker; (b-2) acquiring the coordinates of the center point of the vascular catheter through the coordinates of the center point of the shape sensor; and (b-3) calculating a transformation relationship between the reference coordinate system and the coordinate system of the shape sensor.

According to an embodiment of the present invention, step (c) sets the initial value of the state variable by calculating the quaternion of the unit center line connecting the blood vessel center points from the position coordinates of the blood vessel center points (c-1). steps; (c-2) calculating the mass of the blood vessel center point and the mass moment of inertia of the unit center line using the density of blood vessels, the radius of the blood vessel center line model stored for each blood vessel center point, and the length of the unit center line; and (c-3) setting the unit element to have at least two unit center lines and blood vessel center points at both ends of each unit center line.

According to an embodiment of the present invention, step (d) includes (d-1) calculating the stiffness and internal force of the unit element by considering the influence of the adjacent elements; and (d-2) calculating the deformation of the unit element based on the stiffness and internal force of the unit element.

According to an embodiment of the present invention, the step (d-2) includes setting a blood vessel center point corresponding to each catheter center point among the plurality of blood vessel center points as a constraint node; calculating a force acting on the unit element so that the displacement of the constraint node satisfies conditions 1 and 2 below; and

(Condition 1)

(Condition 2)

( : vessel radius, : Blood vessel center point due to catheter insertion force acting on, : Distance between the center point of the blood vessel and the center point of the catheter after registration)

It may include calculating the deformation of the unit element according to the force acting on the unit element.

According to the present invention, more accurate registration is possible by acquiring three-dimensional information from a shape sensor during a procedure and simulating the deformation of a blood vessel in real time when inserting a vascular catheter equipped with a shape sensor into a blood vessel.

Figure 1 is a flowchart showing each step of a method for simulating blood vessel deformation by catheter insertion in a vascular interventional procedure according to the present invention.
Figure 2 is a diagram showing the discretized Cosserat rod model applied to the unit element division step of Figure 1.
FIG. 3 is a diagram illustrating unit elements for use in calculating deformation of the blood vessel centerline model in the unit element division step of FIG. 1 .
FIG. 4 is a diagram illustrating a group that is a set of unit elements exclusively constructed from the blood vessel centerline model in the unit element division step of FIG. 1.
FIG. 5 is a diagram schematically showing the process of calculating the deformation of a unit element in the unit element deformation calculation step of FIG. 1.
Figure 6 is a diagram showing the force acting on the blood vessel so that the blood vessel center line is aligned with the catheter center line in the deformation calculation step of Figure 1. Figure 6(a) shows the state before registration, and Figure 6(b) shows the state after registration.

Hereinafter, specific details for implementing the present invention will be described with reference to the attached drawings. Also, in describing the present invention, if it is determined that related known functions may unnecessarily obscure the gist of the present invention as they are obvious to those skilled in the art, the detailed description thereof will be omitted.

Figure 1 is a flowchart showing each step of a method for simulating blood vessel deformation by catheter insertion in a vascular interventional procedure according to the present invention.

Referring to Figure 1, the method for simulating blood vessel deformation by catheter insertion in vascular interventional procedures according to the present invention includes a blood vessel center line model acquisition step (s10), an initial registration performance step (s20), a unit element division step (s30), It includes a unit element deformation calculation step (s40). Each of the above steps is performed by the operation unit of the processor.

The blood vessel center line model acquisition step (s10) is a step of generating a three-dimensional blood vessel model of the patient from a medical image of the patient taken before the procedure and obtaining a blood vessel center line model having a plurality of blood vessel center points extracted from the three-dimensional blood vessel model. . The blood vessel centerline model acquisition step (s10) includes a three-dimensional blood vessel model extraction step (s11) and a blood vessel centerline model construction step (s12). In the 3D blood vessel model extraction step (s11), a 3D blood vessel model is first created by taking medical images of the patient before the procedure. The medical image may be computed tomography angiography (CTA) or magnetic resonance angiography (MRA). In the acquired image, pixels corresponding to blood vessels have a brightness value that distinguishes them from surrounding organs due to the injection of contrast agent. The blood vessel area is extracted from the image, a blood vessel surface model consisting of triangular elements is created, and the center point of the blood vessel cross section is calculated and stored from the surface model. The center point is sampled at regular intervals and used to construct a deformable blood vessel centerline model.

The initial registration performing step (s20) is a step of performing initial registration of obtaining the coordinates of the center point of the vascular catheter and converting the coordinates of the center point of the vascular catheter into coordinate values of the reference coordinate system. The vascular catheter is equipped with a shape sensor. A reference marker for initial registration may be attached to the operating unit of the surgical tool equipped with a shape sensor. The initial registration performance step (s20) includes a reference coordinate system acquisition step (s21), a vascular catheter center point coordinate acquisition step (s22), and a transformation relationship calculation step (s23). The reference coordinate system acquisition step (s21) is a step of acquiring a reference coordinate system using a marker before the procedure begins. The reference coordinate system can be created using optical markers and reference markers provided at set positions inside the operating room. The step s22 of acquiring the coordinates of the center point of the vascular catheter is a step of acquiring the coordinates of the center point of the vascular catheter through the coordinates of the center point of the shape sensor. The coordinate value of the shape sensor center point is acquired in real time based on the shape sensor coordinate system. The transformation relationship calculation step (s23) is a step of calculating the transformation relationship between the reference coordinate system and the coordinate system of the shape sensor. The calculation unit uses the transformation relationship to convert the coordinate value of the shape sensor center point into a coordinate system based on the reference coordinate system. The coordinate value of the shape sensor center point expressed in a reference coordinate system is used as an input value in blood vessel deformation simulation. The calculation unit performs initial registration by converting the coordinate values of the 3D blood vessel model generated in the blood vessel center line model acquisition step (s10) and the sampled blood vessel center line model to fit the reference coordinate system.

Figure 2 is a diagram showing the discretized Cosserat rod model applied to the unit element division step of Figure 1. Figure 2 shows the discretized Cosserat rod model, which is used as the vessel centerline model.

Referring to FIG. 2, the unit element division step s30 is a step of setting an initial value for deforming the blood vessel center line model and dividing the blood vessel center line model into a plurality of unit elements. The plurality of unit elements may be grouped. The step of acquiring the blood vessel center line model (s10), performing the initial registration (s20), and dividing the unit elements (s30) can be performed only once before starting the simulation. The unit element division step (s30) includes a state variable initial value setting step (s31), a mass moment of inertia calculation step (s32), and a unit element setting step (s33).

The state variable initial value setting step (s31) is a step of setting the initial value of the state variable by calculating the quaternion of the unit center line connecting the blood vessel center points from the position coordinates of the blood vessel center points. In the state variable initial value setting step (s31), the initial value of the state variable of the blood vessel center line model is determined using the state variable expression method of the discretized Cosserat rod model to set the initial value for deformation calculation. The state variables of the discretized Cosserat rod model consist of position coordinates and quaternions. In the state variable initial value setting step (s31), the quaternion of the unit center line is calculated from the position coordinates of the blood vessel center point, the initial value of the state variable is set, and an identification ID is assigned to each center line and unit center line as shown in FIG. 2.

The mass moment of inertia calculation step (s32) is a step of calculating the mass of the blood vessel center line and the mass moment of inertia of the unit center line using the density of blood vessels, the radius of the blood vessel center line model stored at each blood vessel center point, and the length of the unit center line. . The calculated mass of the vessel center line and the mass moment of inertia of the unit center line are stored in the database. The density value of the blood vessel may include general values described in existing literature or values measured for each patient.

FIG. 3 is a diagram illustrating unit elements for use in calculating deformation of the blood vessel centerline model in the unit element division step of FIG. 1 .

Referring to FIG. 3, the unit element setting step (s33) is a step of setting the unit element to have at least two unit center lines and blood vessel center points at both ends of each unit center line. The deformation of the vessel centerline model is calculated for each unit element after setting the unit element. The unit element is the minimum unit for calculating deformation and can be defined as a set including a connected center line and center points at both ends of the center line. As illustrated in Figure 3, a unit element may be composed of three center points (indicated by dots and concentric circles) and two center lines (indicated by solid lines) connecting each center point.

FIG. 4 is a diagram illustrating a group that is a set of unit elements exclusively constructed from the blood vessel centerline model in the unit element division step of FIG. 1.

Referring to FIG. 4, after setting initial values such as state variables and connection relationships with adjacent center points and center lines, unit elements are set. When dividing a blood vessel center line model into multiple unit elements, different unit elements are configured exclusively so that they do not contain the same center line or center point. Next, a set of exclusively composed unit elements is defined as a group. Transformations of unit elements within a group can be calculated in parallel. Figure 4 represents different groups. In the unit element division step (s30), unit elements and groups are created until all center points and all center lines are included in one or more groups.

The deformation calculation step (s40) considers the elastic potential energy stored in the unit element due to deformation of adjacent elements adjacent to the unit element so that the corresponding point of the blood vessel center line model can be matched to the center point of the catheter inserted into the blood vessel. This is the step of calculating the deformation of the unit element. The unit element deformation calculation step (s40) includes a stiffness and internal force calculation step (s41) and a deformation calculation step (s42).

The stiffness and internal force calculation step s41 is a step of calculating the stiffness and internal force of the unit element by considering the influence of the adjacent elements. In order to consider the influence of adjacent center points and center lines on the unit element, the stiffness and internal force generated by adjacent center points and center lines are included in the deformation calculation of the unit element. For example, in the calculation of a unit element e _k consisting of the center points i-1, i, i+1 and the center line i-1, i, expressed as a solid line, the displacement of the i center point is calculated using the center point included in the unit element. It includes the stiffness and internal force caused by not only the center points i-1, i, and i+1, but also the center point i+p, which is not included in the unit element. For this calculation, each center line, front and rear center lines of the center line, and the connection relationship to the center line are stored in the database. Calculating the deformation by dividing it into unit elements like this is to quickly calculate the deformation while the force and displacement acting on the blood vessel center line model satisfy the contact problem conditions between two points ('Conditions 1 and 2' below).

FIG. 5 is a diagram schematically showing the process of calculating the deformation of a unit element in the deformation calculation step of FIG. 1.

Referring to FIG. 5, the deformation calculation step s42 is a step of calculating the deformation of the unit element based on the stiffness and internal force of the unit element. It receives input from the center point of the vascular catheter inserted into the blood vessel in real time and calculates the deformation for each frame. The deformation of the unit element is calculated by considering the elastic potential energy of the adjacent center point and center line so that the corresponding point of the blood vessel center line model can be matched to the center point of the catheter inserted into the blood vessel.

The deformation calculation of the deformable body model is done by calculating state variables, such as the coordinates of the nodes constituting the deformable body model, through equations of motion and updating them at every time step. State variables are updated by calculating acceleration, velocity, and displacement by considering the external and internal forces acting on each node constituting the model, and the mass and stiffness of the node. The internal force acting on the node can be calculated by obtaining the first derivative of the elastic potential energy stored in the deformable body model due to elastic deformation of the deformable body model, and the stiffness can be calculated by obtaining the second derivative. Elastic potential energy includes elastic modulus, Poisson's ratio, etc. to include the physical characteristics of the deformable body model.

In detail, the energy according to the state variable of the deformable body model consists of kinetic energy and potential energy (strain energy) as shown in Equation 1 below.

(Formula 1)

In formula 1 above, means kinetic energy, means potential energy (strain energy). Here, minimizing energy Find . Then, the following equation 2 can be defined.

(Formula 2)

Here, A refers to the terms of inertia (mass) and stiffness, which is It can be calculated by finding . Q refers to the state variables of the model, such as the position coordinates of the nodes. B refers to the terms of external force and internal force acting on the node, which is It can be calculated by finding .

In one embodiment, a method for defining elastic potential energy may include a method based on projective dynamics. Projection mechanics defines constraints on the strain rate of elements constituting a deformable body and introduces an auxiliary variable p that satisfies the constraints. The state variable is determined as the least squares solution from p. In general, the strain energy for one element is defined as Equation 3 below. is a constant matrix and is used to extract the state variable of the corresponding element among the state variables that make up the entire model. Weight parameter may include the elastic modulus of the object that the deformable body model is to simulate. The strain energy of the model is expressed as the sum of the strain energies for all elements.

(Formula 3)

Deformation in the vessel centerline model can be caused by stretch, shear, bend, and twist stresses. The auxiliary variable p can be calculated by projecting the state variable to minimize the strain for each stress.

In the deformation calculation step (s42), the elastic potential energy stored in each unit element is calculated and the deformation for each unit element is updated accordingly. At this time, in order to include the influence due to adjacent center points and center lines, the elastic potential energy is calculated as shown in Equation 4 below.

(Formula 4)

In Equation 4 above, means the elastic potential energy stored in the unit element due to deformation of the unit element, means the elastic potential energy stored in a unit element due to deformation between the unit element and adjacent elements.

In Equation 4 above, is the unit element It represents the state variable of , which is as shown in Equation 5 below.

(Formula 5)

The first term in Equation 4 is the elastic potential energy stored in the unit element due to deformation of the unit element. For example, in Figure 3 is the initial coordinate value ( ), stress may occur due to stretch and shear deformation. The elastic potential energy stored due to elongation and shear stress is obtained by substituting Equation 6 below into the first term of Equation 4 above. If changes compared to the initial value, stress may occur due to bending or twisting deformation. in figure 4 The elastic potential energy stored due to bending and torsional stress is obtained by substituting the following equation 7 into the first term of equation 4.

(Formula 6)

(Equation 7)

The second term in Equation 4 is the elastic potential energy stored in the unit element due to the deformation of the center line or center line included in the unit element and the center point or center line adjacent to the unit element. For example, in Figure 3 is the initial coordinate value ( ), stress may occur due to stretch and shear deformation. The elastic potential energy stored due to elongation and shear stress is obtained by substituting Equation 8 below into the second term of Equation 4. If changes compared to the initial value, stress may occur due to bending or twisting deformation. in Figure 3 The elastic potential energy stored due to the bending and torsional stress is obtained by substituting the following equation (9) into the second term of equation (4).

(Equation 8)

(Equation 9)

The deformation calculation step (s42) includes a constraint node setting step (s42a), a unit element action force calculation step (s42b), and a unit element deformation calculation step (s42c).

Figure 6 is a diagram showing the force acting on the blood vessel so that the blood vessel center line is aligned with the catheter center line in the deformation calculation step of Figure 1. Figure 6(a) shows the state before registration, and Figure 6(b) shows the state after registration.

Referring to FIG. 6, the constraint node setting step (s42a) is a step of setting a blood vessel center point corresponding to each catheter center point among the plurality of blood vessel center points as a constraint node.

The unit element force calculation step (s42b) is a step of calculating the force acting on the unit element so that the displacement of the constraint node satisfies conditions 1 and 2 below. In order to ensure that the center line of the blood vessel is aligned with the center line of the catheter, Equation 2 above is defined to satisfy Equation 8 below. Figure 6 shows the blood vessel centerline model divided into unit elements (thick solid lines). The dimension of the unit element is m(n >> m), and the size of the A matrix is m x m.

(Equation 8)

In Equation 8 above, the state variables q and F _contact for each unit element are iteratively calculated to satisfy the following conditions 1 and 2. At this time, unit elements within one group are configured so as not to overlap each other, so that calculation of unit elements within the same group is possible in parallel. At this time, the group is configured so that the unit element can be included in at least one group.

(Condition 1)

(Condition 2)

( : vessel radius, : Center point of blood vessel due to catheter insertion during the above F _contact force acting on, : Distance between the center point of the blood vessel and the center point of the catheter after registration)

The unit element deformation calculation step (s42c) is a step of calculating the deformation of the unit element according to the force acting on the unit element.

The reason for updating the transformation for each unit element is as follows. When a catheter is inserted into a blood vessel, the deformation of the blood vessel caused by the force that the catheter exerts on the inner wall of the blood vessel can be modeled as a contact problem between two central points, which can be solved by calculating the displacement of the blood vessel that satisfies conditions 1 and 2 above. do.

When a vascular catheter equipped with a 3D shape sensor is inserted into a blood vessel, the deformation of the blood vessel varies depending on the anatomical structure of the blood vessel, physical characteristics, and the shape of the inserted catheter. The deformation of the vessel centerline model considering the above matters must be calculated globally for all state variables included in the vessel centerline model, but it is difficult to globally calculate the deformation that satisfies the above conditions in real time. According to the present invention, by dividing into unit elements and satisfying constraints added by newly input variables, such as insertion of a catheter, for each unit element, the transformation is quickly calculated and the constraint of Equation 8 is satisfied. can be calculated. The deformation calculation of the unit element can be calculated in parallel within the same group shown in Figure 4, and the calculation of each group is carried out sequentially and repeatedly.

The scope of protection in this field is not limited to the description and expression of the embodiments explicitly described above. In addition, it is added once again that the scope of protection of the present invention may not be limited due to changes or substitutions that are obvious in the technical field to which the present invention pertains.

Claims (6)

A method of simulating blood vessel deformation due to catheter insertion in vascular interventional procedures, performed by a calculation unit of a processor, wherein the calculation unit includes:
(a) generating a 3D blood vessel model of the patient from a medical image of the patient, and obtaining a blood vessel center line model having a plurality of blood vessel center points extracted from the 3D blood vessel model;
(b) obtaining the coordinates of the center point of the vascular catheter and performing initial registration of converting the vascular center line model and the coordinates of the center point of the vascular catheter into coordinate values of a reference coordinate system;
(c) setting an initial value for deforming the blood vessel center line model and dividing the blood vessel center line model into a plurality of unit elements; and
(d) the unit element in consideration of the elastic potential energy stored in the unit element due to deformation of adjacent elements adjacent to the unit element so that the corresponding point of the blood vessel center line model can be matched to the center point of the catheter inserted into the blood vessel A method of simulating vascular deformation due to catheter insertion in vascular interventional procedures, comprising the step of calculating the deformation of .
According to paragraph 1,
In step (a),
(a-1) extracting the 3D blood vessel model from the medical image of the patient; and
(a-2) A method for simulating blood vessel deformation by catheter insertion in vascular interventional procedures, comprising the step of constructing the blood vessel center line model by sampling the center line of the extracted three-dimensional blood vessel model at regular intervals.
According to paragraph 1,
The vascular catheter is equipped with a shape sensor,
In step (b),
(b-1) acquiring a reference coordinate system using a marker;
(b-2) acquiring the coordinates of the center point of the vascular catheter through the coordinates of the center point of the shape sensor; and
(b-3) A method for simulating vascular deformation due to catheter insertion in vascular interventional procedures, comprising the step of calculating a transformation relationship between the reference coordinate system and the coordinate system of the shape sensor.
According to paragraph 1,
In step (c),
(c-1) setting an initial value of a state variable by calculating a quaternion of a unit center line connecting the blood vessel center points from the position coordinates of the blood vessel center points;
(c-2) calculating the mass of the blood vessel center point and the mass moment of inertia of the unit center line using the density of blood vessels, the radius of the blood vessel center line model stored for each blood vessel center point, and the length of the unit center line; and
(c-3) setting the unit element to have at least two unit center lines and blood vessel center points at both ends of each unit center line. Blood vessel deformation caused by catheter insertion in a vascular interventional procedure. Simulation method.
According to paragraph 1,
In step (d),
(d-1) calculating the stiffness and internal force of the unit element considering the influence of the adjacent elements; and
(d-2) A method for simulating vascular deformation due to catheter insertion in vascular interventional procedures, comprising the step of calculating deformation of the unit element based on the stiffness and internal force of the unit element.
According to clause 5,
In step (d-2),
setting a blood vessel center point corresponding to each catheter center point among the plurality of blood vessel center points as a constraint node;
calculating a force acting on the unit element so that the displacement of the constraint node satisfies conditions 1 and 2 below; and
(Condition 1)
(Condition 2)
( : vessel radius, : Blood vessel center point due to catheter insertion force acting on, : Distance between the center point of the blood vessel and the center point of the catheter after registration)
A method for simulating vascular deformation due to catheter insertion in vascular interventional procedures, comprising calculating deformation of the unit element according to a force acting on the unit element.