Preoperative planning method based on built-in sensor of aorta root model

Abstract

The invention provides a preoperative planning method based on a built-in sensor of an aorta root model, which comprises the following steps: establishing a digital model of the aorta root according to heart CT (Computed Tomography) image data of a patient, the digital model comprising a valve area to be implanted; an annular channel consistent with the internal curve of the to-be-implanted valve area is arranged in the wall body of the to-be-implanted valve area; preparing a simulation model of the aorta root according to the digital model with the annular channel; inserting one end of a positive electrode and one end of a negative electrode into the annular channel of the simulation model, then injecting an ionized hydrogel precursor, and freezing, so that the ionized hydrogel sensor is arranged in the simulation model; detecting a resistance value generated by the ionized water gel sensor by each artificial valve at the same position or different positions of a valve area to be implanted of the simulation model; and determining the model and / or implantation position of the artificial valve according to the resistance value.

Description

Technical Field

[0001] This invention relates to the field of medical technology, and more specifically, to a preoperative planning method based on sensors built into an aortic root model. Background Technology

[0002] With the accelerating aging of the global population, the incidence of aortic valve disease has risen significantly, becoming one of the major cardiovascular diseases threatening the health of the elderly. Traditional open-heart surgery, due to its high trauma, high risk, and need for cardiopulmonary bypass, is gradually being replaced by minimally invasive transcatheter aortic valve replacement (TAVR). TAVR implants an artificial valve through a catheter, eliminating the need for open-heart surgery, and has the advantages of minimal trauma and rapid recovery, making it particularly suitable for elderly and frail patients. However, current TAVR preoperative planning mainly relies on the doctor's experience and imaging examinations, lacking individualized and precise quantitative data. This can lead to inappropriate valve selection and implantation location, a lack of precise basis for preoperative optimization, and postoperative risks of complications such as paravalvular leakage and conduction disorders, affecting the surgical outcome and success rate. Summary of the Invention

[0003] This invention provides a new technical solution for preoperative planning based on sensors embedded in an aortic root model, which can at least solve the technical problem that the lack of accurate basis for preoperative planning in valve replacement surgery is not conducive to optimizing valve selection and implantation scheme.

[0004] According to a first aspect of the present invention, a preoperative planning method based on an aortic root model with an embedded sensor is provided, comprising: establishing a digital model of the aortic root based on a patient's cardiac CT image data, the digital model including a valve region to be implanted; providing an annular channel within the wall of the valve region to be implanted, the annular channel having an internal curve consistent with the annular channel; preparing a simulation model of the aortic root based on the digital model having the annular channel; inserting one end of a positive electrode and one end of a negative electrode into the annular channel of the simulation model, followed by injecting an ionized hydrogel precursor and freezing, so that an ionized hydrogel sensor is embedded within the simulation model; detecting the resistance value generated by the ionized hydrogel sensor at the same or different locations in the valve region to be implanted in the simulation model for each artificial valve; and confirming the type and / or implantation location of the artificial valve based on the resistance value.

[0005] Optionally, the method for determining the type and / or implantation location of the artificial valve based on the electrical resistance value includes: determining the corresponding pressure value based on the resistance value; and determining the type and / or implantation location of the artificial valve based on the corresponding pressure value.

[0006] Optionally, the preoperative planning method further includes: calibrating the ion hydrogel sensor, wherein the calibration method includes: establishing a relationship curve between the resistance and pressure of the ion hydrogel sensor; fitting the relationship curve; and establishing a calibration equation based on the fitting result.

[0007] Optionally, the preoperative planning method further includes storing the calibration equation in a control unit.

[0008] Optionally, the method for preparing the ionic hydrogel precursor is as follows: dissolving polyvinyl alcohol in a lithium chloride solution; uniformly dispersing the dye in the lithium chloride solution to obtain the ionic hydrogel precursor.

[0009] Optionally, the temperature at which the polyvinyl alcohol is dissolved is 95°C to 100°C.

[0010] Optionally, the dye is a water-soluble dye.

[0011] Optionally, the freezing temperature of the ionic hydrogel precursor is -18°C to -25°C, and the freezing time is 1 hour to 2 hours.

[0012] Optionally, the digital model includes the left coronary artery, the valve region to be implanted is a region extending downward from the lower edge of the left coronary artery by 2cm to 4cm, the length of the annular channel is the same as the length of the valve region to be implanted, and the difference between the inner and outer diameters of the annular channel is 1.5mm.

[0013] Optionally, the simulation model is prepared by 3D printing, and the hardness of the simulation model is 30A.

[0014] According to the preoperative planning method based on an aortic root model with built-in sensors of the present invention, the ionized hydrogel sensor installed within the simulation model of the aortic root can generate different resistance values ​​according to the type and location of the implanted artificial valve. Different resistance values ​​correspond to different postoperative risks and clinical outcomes, which can guide the surgeon in preoperative simulation selection and adjustment of implantation depth and angle, reduce the risk of paravalvular leakage and conduction block, and shift preoperative planning from experience-based to precise quantification, significantly improving the success rate of surgery. Simultaneously, the ionized hydrogel sensor installed within the simulation model has a fast response speed, effectively ensuring the efficiency of preoperative planning.

[0015] Other features and advantages of the invention will become clear from the following detailed description of exemplary embodiments of the invention with reference to the accompanying drawings. Attached Figure Description

[0016] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of the invention and, together with their description, serve to explain the principles of the invention.

[0017] Figure 1 This is one of the structural schematic diagrams of a simulation model according to an embodiment of the present invention;

[0018] Figure 2This is a second schematic diagram of the structure of a simulation model according to an embodiment of the present invention;

[0019] Figure 3 This is the resistance-pressure relationship curve and fitting curve of the ion hydrogel sensor;

[0020] Figure 4 This is a graph showing the resistance response and recovery time characteristics of an ion-hydrogel sensor.

[0021] Figure Labels

[0022] 100. Simulation model; 10. Left coronary artery; 20. Circular channel. Detailed Implementation

[0023] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention.

[0024] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use.

[0025] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0026] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0027] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0028] The preoperative planning method based on an aortic root model with built-in sensors according to an embodiment of the present invention includes: S100 to S600.

[0029] S100. Establish a digital model of the aortic root based on the patient's cardiac CT image data, wherein the digital model includes the area of ​​the valve to be implanted.

[0030] Specifically, the patient's heart is first scanned using a CT scanner, and cardiac CT image data that meets the reconstruction requirements is obtained. Then, the cardiac CT image data is imported into medical image processing software, such as Mimics software, and the cardiac CT image data is segmented using Mimics software to create a digital model including the aortic root of the valve to be implanted. After that, the digital model is processed and repaired to ensure that the surface of the model is smooth, while not changing the shape and boundaries of the model. After the repair is completed, the required digital model is obtained.

[0031] S200: An annular channel 20 with an internal curve is provided in the wall of the valve area to be implanted;

[0032] In detail, the digital model of the aortic root includes the left coronary artery 10 and the left ventricular outflow tract, which is located below the left coronary artery 10. The area to be implanted with the valve is a region in the digital model extending downwards from the lower edge of the left coronary artery 10 for a predetermined length, which can be determined according to actual needs. Within the wall of the area to be implanted with the valve, an annular channel 20 matching the internal curve of the region is provided, which is used for subsequent deployment of flexible sensors.

[0033] S300. Prepare a simulation model 100 of the aortic root based on the digital model having the annular channel 20;

[0034] Specifically, the simulation model 100 can be prepared using inkjet printing technology, such as a multi-material 3D printer, by selecting photosensitive resin material and using layer-by-layer printing technology to complete the model forming. After forming, the external support material of the model is removed, and the surface of the model is polished. After polishing, the simulation model 100 with the annular channel 20 is obtained.

[0035] S400. Insert one end of the positive electrode and one end of the negative electrode into the annular channel 20 of the simulation model 100, then inject the ion hydrogel precursor and freeze it, so that the ion hydrogel sensor is built into the simulation model 100.

[0036] In detail, both the positive and negative electrodes can be made of silver-plated copper wire with a diameter of 0.15 mm. In preparing the ion hydrogel sensor, firstly, one end of each of the two silver-plated copper wires is inserted into the annular channel 20, serving as the positive and negative electrodes respectively. Next, the ion hydrogel precursor is injected into the annular channel 20 using a 10 ml syringe equipped with a No. 7 needle. Finally, the simulation model 100 is placed in a freezer for freezing. After freezing, the ion hydrogel sensor embedded in the simulation model 100 is obtained.

[0037] S500: Detect the resistance value generated by the ion hydrogel sensor at the same or different positions of each artificial valve in the valve area to be implanted in the simulation model 100.

[0038] In other words, during use, the ionogel sensor is electrically connected to the micro-electrochemical workstation, and the artificial valve is installed in the corresponding implantation area of ​​the simulation model 100; that is, the position of the artificial valve corresponds to the position of the ionogel sensor. This pressure causes the ionogel sensor to deform, thereby changing its resistance value. The resistance value of the ionogel sensor can be accurately detected using the micro-electrochemical workstation. By changing the installation position of the artificial valve or changing the model of the artificial valve, the resistance value of the ionogel sensor under different conditions can be detected.

[0039] S600. Confirm the type of artificial valve and / or the implantation location based on the resistance value.

[0040] Specifically, different resistance value ranges correspond to different postoperative risks and clinical outcomes. Therefore, based on the measured resistance values, doctors can determine the type of artificial valve and its implantation location, thereby enabling precise preoperative simulation selection and adjusting the valve's implantation depth and angle accordingly.

[0041] Therefore, the preoperative planning method based on an aortic root model with built-in sensors provided in this embodiment of the present invention, through the ionized hydrogel sensor installed within the simulation model 100 at the aortic root, can generate different resistance value changes according to the type and location of the implanted artificial valve. Different resistance values ​​correspond to different postoperative risks and clinical outcomes, which can guide the surgeon in preoperative simulation selection and adjustment of implantation depth and angle, reduce the risk of paravalvular leakage and conduction block, and shift preoperative planning from experience-based to precise quantification, significantly improving the success rate of surgery. Simultaneously, the ionized hydrogel sensor installed within the simulation model 100 has a fast response speed, effectively ensuring the efficiency of preoperative planning.

[0042] In some specific embodiments of the present invention, the method for confirming the type and / or implantation location of the artificial valve based on the resistance value includes: S610 and S620.

[0043] S610. Confirm the corresponding pressure value based on the resistance value;

[0044] S620. Confirm the model and / or implantation location of the artificial valve based on the corresponding pressure value.

[0045] In other words, different resistance values ​​correspond to different pressure values, and different pressure values ​​correspond to different postoperative risks and clinical outcomes. When confirming the type and / or implantation location of an artificial valve, the corresponding pressure value can first be determined based on the resistance value detected by the micro-electrochemical workstation, and then the type and / or implantation location of the artificial valve can be determined based on this pressure value.

[0046] Studies have shown that if the maximum contact pressure (CPMax) in the implanted valve area is ≥0.40 MPa (≈400 kPa), the risk of new-onset conduction block (CA) after surgery increases significantly. If the implantation depth is adjusted during surgery to make the CPMax in that area lower than 0.08 MPa (approximately 80 kPa), the incidence of conduction block can be significantly reduced. However, if the CPMax is too low, approximately between 0.04 MPa and 0.05 MPa (i.e., 40 kPa and 50 kPa), it indicates that the valve stent of the artificial valve does not fit tightly enough with the tissue, thereby increasing the risk of paravalvular leakage (PVL).

[0047] Based on this, the present invention determines the corresponding pressure value by measuring the resistance value of the ion hydrogel sensor, which can provide doctors with a scientific basis for accurately selecting the artificial valve model and determining the implantation location before surgery. This can effectively reduce the risk of new conduction block and paravalvular leakage after surgery, and can significantly improve the success rate of surgery and the postoperative quality of life of patients.

[0048] In some specific embodiments of the present invention, the method for confirming the model and / or implantation location of the artificial valve based on the corresponding pressure value is as follows: determine whether the corresponding pressure value is within the target pressure range; if the corresponding pressure value is within the target pressure range (e.g., 55 kPa < target pressure < 80 kPa), then confirm the model and / or location of the artificial valve; if the corresponding pressure value is not within the target pressure range, then suggest adjusting the model or implantation location of the artificial valve until the corresponding pressure value is within the target pressure range.

[0049] According to one embodiment of the present invention, the preoperative planning method further includes: calibrating the ionogel sensor, the calibration method comprising:

[0050] Establish the relationship curve between the resistance and pressure of the ion hydrogel sensor;

[0051] The relationship curve is fitted, and a calibration equation is established based on the fitting result.

[0052] In other words, to ensure the accuracy of obtaining the corresponding pressure, the simulation model 100 is first placed on a digital scale, and the ion-hydrogel sensor built into the simulation model 100 is connected to a micro-electrochemical workstation. Then, a stainless steel replica of an artificial valve in its released state is used to apply multiple pressure-release cycles to the ion-hydrogel sensor within the valve area to be implanted. During this process, the force applied during each pressure-release cycle is measured using the digital scale, and the pressure is calculated based on the force-bearing area, as shown in Table 1. Simultaneously, the change in device resistance during each pressure-release cycle is recorded using the micro-electrochemical workstation. By analyzing the above data, a curve relating the resistance of the ion-hydrogel sensor to the pressure can be established. Finally, the curve is fitted using the least squares method to obtain the corresponding equation, which is the calibration equation. When confirming the corresponding pressure value, the measured resistance value is substituted into the calibration equation to calculate the corresponding pressure value.

[0053] Table 1. Pressure corresponding to different forces applied to the artificial valve stent.

[0054]

[0055] In one embodiment of the present invention, the above-mentioned relationship curve is fitted to obtain the calibration equation as: y = 5.10352 + 1.00387x + 0.00115x 2 .

[0056] In some specific embodiments of the present invention, the preoperative planning method further includes storing the calibration equation in a control unit.

[0057] In this embodiment, by storing the calibration equation in the control unit, it can be ensured that the resistance value of the ion hydrogel sensor can be quickly and accurately converted into a pressure value through the calibration equation during actual measurement, effectively avoiding human error and improving the reliability and accuracy of the measurement results.

[0058] According to one embodiment of the present invention, the method for preparing the ion hydrogel precursor is as follows:

[0059] Polyvinyl alcohol was dissolved in lithium chloride solution;

[0060] The dye was uniformly dispersed in the lithium chloride solution to obtain an ionic hydrogel precursor.

[0061] In other words, the ion-hydrogel precursor mainly consists of polyvinyl alcohol (PVA) and a lithium chloride solution, wherein the PVA content is 3 wt% to 10 wt%, for example, 3 wt%, 5 wt%, 7 wt%, and 10 wt%. During preparation, PVA is dissolved in an 8M lithium chloride solution. Furthermore, to facilitate subsequent observation of the hydrogel within the annular channel 20, the ion-hydrogel precursor also includes 0.3 wt% to 0.5 wt% of a dye, which can be methylene blue dye. After dissolving PVA in the lithium chloride solution, the dye is added and thoroughly stirred to achieve uniform mixing, thus obtaining the ion-hydrogel precursor solution containing the dye.

[0062] In some specific embodiments of the present invention, the temperature for dissolving the polyvinyl alcohol is 95°C to 100°C, for example, 95°C, 96°C, 97°C and 100°C. Within this temperature range, the polyvinyl alcohol can be dissolved, thereby ensuring the reliability of the ion hydrogel sensor.

[0063] According to one embodiment of the present invention, the dye is a water-soluble dye, which can be well dispersed in an aqueous solution, ensuring that the dye is uniformly distributed in the lithium chloride solution, and effectively avoiding differences in hydrogel properties caused by uneven dye distribution.

[0064] In some specific embodiments of the present invention, the freezing temperature of the ion hydrogel precursor is -18°C to -25°C, for example, -18°C, -20°C, -22°C, and -25°C, and the freezing time is 1 hour to 2 hours, for example, 1 hour, 1.2 hours, 1.5 hours, 1.7 hours, and 2 hours. By freezing the ion hydrogel precursor at a temperature of 18°C ​​to -25°C for 1 hour to 2 hours, a uniform and stable hydrogel network structure can be formed, thereby ensuring the reliability of the ion hydrogel sensor.

[0065] According to one embodiment of the present invention, the digital model includes a left coronary artery 10, the valve region to be implanted is a region extending downward from the lower edge of the left coronary artery 10 by 2cm to 4cm, the length of the annular channel 20 is the same as the length of the valve region to be implanted, and the difference between the inner and outer diameters of the annular channel 20 is 1.5mm.

[0066] In other words, the length of the ionized hydrogel sensor in the simulation model 100 is the same as that of the valve area to be implanted, which is 2cm to 4cm, such as 2cm, 2.5cm, 3cm, 3.5cm and 4mm, etc. The wall thickness of the ionized hydrogel sensor is 1.5mm, and the ionized hydrogel sensor extends downward from the lower edge of the left coronary artery 10 of the simulation model 100.

[0067] In this embodiment, by setting the length of the ion hydrogel sensor to 2cm to 4cm and the wall thickness to 1.5mm, not only can the actual use requirements be met, but the material waste caused by excessive size can also be effectively avoided.

[0068] In some specific embodiments of the present invention, the simulation model 100 is prepared by 3D printing, and the hardness of the simulation model 100 is 30A. This hardness of the simulation model 100 is close to the hardness of actual human tissue, thereby ensuring the accuracy and reliability of preoperative surgical planning.

[0069] According to one embodiment of the present invention, in step S400, 1g of polyvinyl alcohol (PVA), 6.8g of lithium chloride (LiCl), and 0.1g of methylene blue dye are first added to a single-necked flask containing 20g of deionized water. The flask is then heated to 95°C and continuously stirred until all components are completely dissolved, thereby obtaining the desired ionized hydrogel precursor solution. After the 3D-printed solid model has completely solidified, one end of two 0.15mm diameter silver-plated copper wires is inserted into the annular channel 20. Next, the ionized hydrogel precursor solution is injected into the channel using a 10ml syringe equipped with a No. 7 needle. Finally, the solid model is placed in a freezer at -20°C for 1.5 hours to allow the hydrogel to solidify.

[0070] In this embodiment of the invention, the ion-hydrogel sensor has a fast response and recovery time. The response time of the pressure sensor refers to the time elapsed from the application of strain to the change in hydrogel resistance. The recovery time refers to the time elapsed from the start of strain unloading to the recovery of the hydrogel resistance. Figure 2 As can be seen, the response time of the ion-hydrogel sensor in this embodiment of the invention is approximately 0.21 s, and the recovery time is approximately 0.30 s. Therefore, it can be ensured that the ion-hydrogel sensor can quickly and accurately convert resistance changes into electrical signals under dynamic pressure changes, thereby effectively improving detection efficiency. Furthermore, this ion-hydrogel sensor has a high conductivity of 2.6 S / m, thus enabling faster response to pressure changes and reducing signal delay.

[0071] In summary, the preoperative planning method based on an aortic root model with built-in sensors provided in this embodiment of the present invention, through the ionized hydrogel sensor installed within the simulation model 100 at the aortic root, can generate different resistance values ​​according to the type and location of the implanted artificial valve. Different resistance values ​​correspond to different postoperative risks and clinical outcomes, guiding physicians in preoperative simulation selection and adjustment of implantation depth and angle. This can reduce the risk of paravalvular leakage and conduction block, shifting preoperative planning from experience-based to precise quantification, and significantly improving the success rate of surgery. Simultaneously, the ionized hydrogel sensor installed within the simulation model 100 has a fast response speed, effectively ensuring the efficiency of preoperative planning.

[0072] The above embodiments mainly describe the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. For the sake of brevity, they will not be elaborated here.

[0073] While specific embodiments of the invention have been described in detail by way of examples, those skilled in the art should understand that the examples are for illustrative purposes only and not intended to limit the scope of the invention. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.

Claims

1. A preoperative planning method based on sensors embedded in an aortic root model, characterized in that, include: A digital model of the aortic root is created based on the patient's cardiac CT imaging data, and the digital model includes the area of ​​the valve to be implanted. An annular channel, consistent with the internal curve, is provided within the wall of the area to be implanted valve. A simulation model of the aortic root is prepared based on the digital model with an annular channel; One end of the positive electrode and one end of the negative electrode are inserted into the annular channel of the simulation model, and then the ion hydrogel precursor is injected and frozen to embed the ion hydrogel sensor inside the simulation model. The resistance value generated by the ion hydrogel sensor at the same or different positions in the valve area to be implanted in the simulation model is detected for each artificial valve. The type of artificial valve and / or the implantation location are determined based on the resistance value.

2. The preoperative planning method according to claim 1, characterized in that, Methods for determining the type and / or implantation location of the artificial valve based on the electrical resistance value include: The corresponding pressure value is determined based on the resistance value; The model of the artificial valve and / or the implantation location are determined based on the corresponding pressure value.

3. The preoperative planning method according to claim 1, characterized in that, Also includes: The ion hydrogel sensor is calibrated, and the calibration method includes: Establish the relationship curve between the resistance and pressure of the ion hydrogel sensor; The relationship curve is fitted, and a calibration equation is established based on the fitting result.

4. The preoperative planning method according to claim 3, characterized in that, Also includes: The calibration equations are stored in the control unit.

5. The preoperative planning method according to claim 1, characterized in that, The method for preparing the ion hydrogel precursor is as follows: Dissolve polyvinyl alcohol in lithium chloride solution; The dye was uniformly dispersed in the lithium chloride solution to obtain an ionic hydrogel precursor.

6. The preoperative planning method according to claim 5, characterized in that, The temperature at which the polyvinyl alcohol is dissolved is 95℃~100℃.

7. The preoperative planning method according to claim 5, characterized in that, The dye is a water-soluble dye.

8. The preoperative planning method according to claim 1, characterized in that, The freezing temperature of the ionic hydrogel precursor is -18℃ to -25℃, and the freezing time is 1h to 2h.

9. The preoperative planning method according to claim 1, characterized in that, The digital model includes the left coronary artery, and the valve region to be implanted is a region extending downward from the lower edge of the left coronary artery by 2cm to 4cm. The length of the annular channel is the same as the length of the valve region to be implanted, and the difference between the inner and outer diameters of the annular channel is 1.5mm.

10. The preoperative planning method according to claim 1, characterized in that, The simulation model is prepared by 3D printing, and the hardness of the simulation model is 30A.

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