Method for generating trabecular bone porous structure model and preparing trabecular bone porous structure

Abstract

The present invention discloses a method for generating a trabecular porous structure model based on cancellous bone micro-CT and preparing a trabecular porous structure, and relates to the field of biomedical technology. A specific implementation of the method for generating a trabecular porous structure model based on cancellous bone micro-CT includes: scanning the cancellous bone based on micro-CT to obtain a three-dimensional image of the cancellous bone; determining the position of the cavity of the cancellous bone according to the gray value of each point in the three-dimensional image; and generating a trabecular porous structure model based on the Voronoi algorithm according to the cavity position. This implementation can reproduce the microstructure, density distribution, mass transfer characteristics and biological properties of the bone, and at the same time has good mechanical properties and bone ingrowth properties.

Description

Technical Field

[0001] The invention relates to the field of biomedical technology, and in particular to a method for generating a trabecular porous structure model based on cancellous bone micro-CT and preparing the trabecular porous structure. Background Art

[0002] Trabeculae are the extension of cortical bone in cancellous bone, that is, trabeculae are connected to cortical bone, and present an irregular three-dimensional network structure in the bone marrow cavity, such as loofah or sponge, which plays a role in supporting hematopoietic tissue. When stimulated by external forces, trabeculae show deformation, reduced density, and enlarged pores in the network structure. When the trabeculae are subjected to a certain strength, diffuse fractures will occur, the integrity will be destroyed, and the strength provided by the cancellous bone will be reduced, which will lead to a decrease in bone deformation resistance and load-bearing capacity.

[0003] At present, bone defects can be repaired clinically through allogeneic bone transplantation. As a bone implant material for allogeneic bone transplantation, it should fully mimic the properties of bones, from mechanical properties, biological properties, mass transfer characteristics to microstructural characteristics, to produce similar cell penetration, nutrient diffusion and bone conduction properties. In addition, the design of the bone scaffold should provide an optimized mechanical environment so that bone cells can obtain the necessary nutrients and signals to simulate bone healing. An unmatched mechanical environment will lead to reduced bone regeneration. Summary of the invention

[0004] In view of this, an embodiment of the present invention provides a method for generating a trabecular porous structure model and preparing a trabecular porous structure based on cancellous bone micro-CT, which can reproduce the microstructure, density distribution, mass transfer characteristics and biological properties of bones, and at the same time has good mechanical properties and bone ingrowth performance.

[0005] To achieve the above object, according to a first aspect of an embodiment of the present invention, a method for generating a trabecular porous structure model based on cancellous bone micro-CT is provided, comprising:

[0006] Scan the cancellous bone based on micro-CT to obtain a three-dimensional image of the cancellous bone;

[0007] Determining the location of the cavity in the cancellous bone according to the gray value of each point in the three-dimensional image;

[0008] According to the cavity positions, a trabecular porous structure model is generated based on the Voronoi algorithm.

[0009] Optionally, determining the position of the cavity in the cancellous bone according to the gray value of each point in the three-dimensional image includes:

[0010] According to the grayscale value of each point in the three-dimensional image, determining the minimum value point of the grayscale value of each point;

[0011] The minimum point is taken as the hole position of the cancellous bone.

[0012] According to a second aspect of an embodiment of the present invention, a method for preparing a trabecular porous structure based on cancellous bone micro-CT is provided, comprising:

[0013] The method of the first aspect of the embodiment of the present invention is used to generate a trabecular porous structure model;

[0014] The trabecular porous structure model is printed by additive manufacturing to obtain the trabecular porous structure.

[0015] Optionally, the material used for printing the trabecular porous structure model is: ceramic, or polymer, or composite material.

[0016] According to a third aspect of the embodiments of the present invention, there is provided a trabecular porous structure obtained by the method according to the second aspect of the embodiments of the present invention.

[0017] One embodiment of the above invention has the following advantages or beneficial effects: the present invention scans cancellous bone based on micro-CT, and can obtain the density distribution information of bones in space at the micron level. According to the position of the holes, a trabecular porous structure model is generated based on the Voronoi algorithm, which can not only retain the important information of the bone in the trabecular porous structure, but also has flexibility and versatility. The trabecular porous structure obtained by the method of the embodiment of the present invention can reproduce the microstructure, density distribution, mass transfer characteristics and biological properties of the bone. The stiffness of the trabecular porous structure can reach the state of matching cancellous bone to avoid stress shielding. At the same time, the optimized pore size and topological structure can create a good environment for bone ingrowth. The trabecular porous structure obtained by the embodiment of the present invention can be used as various orthopedic implants to improve the comprehensive performance of the product.

[0018] The further effects of the above-mentioned non-conventional optional manner will be described below in conjunction with the specific implementation manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings are used to better understand the present invention and do not constitute an improper limitation of the present invention.

[0020] Figure 1 is a schematic diagram of a point set reflecting the location of cancellous bone cavities in an embodiment of the present invention;

[0021] Figure 2 is a schematic diagram of a Voronoi trabecular bone structure topology framework generated according to a point set of a cavity position in an embodiment of the present invention;

[0022] Figure 3 is a schematic diagram of a trabecular porous structure model in an embodiment of the present invention;

[0023] Figure 4 is a schematic diagram of a layer in a microstructural scan of the human trabecular bone structure;

[0024] Figure 5 This is a schematic diagram of the three-dimensional model of trabecular bone structure obtained by direct remodeling based on micro-CT. DETAILED DESCRIPTION

[0025] The following is a description of exemplary embodiments of the present invention in conjunction with the accompanying drawings, including various details of the embodiments of the present invention to facilitate understanding, which should be considered as merely exemplary. Therefore, it should be recognized by those of ordinary skill in the art that various changes and modifications may be made to the embodiments described herein without departing from the scope and spirit of the present invention. Similarly, for clarity and conciseness, the description of well-known functions and structures is omitted in the following description.

[0026] According to a first aspect of an embodiment of the present invention, a method for generating a trabecular porous structure model based on cancellous bone micro-CT is provided, comprising step S101, step S102 and step S103.

[0027] In step S101, the cancellous bone is scanned based on micro-CT to obtain a three-dimensional image of the cancellous bone.

[0028] Micro CT (micro computed tomography), also known as micro CT, is a non-destructive 3D imaging technology that can clearly understand the internal microscopic structure of the sample without destroying the sample. The biggest difference between it and ordinary clinical CT is that its resolution is extremely high, reaching the micron (μm) level, so it has a good "microscopic" effect. By scanning the cancellous bone based on micro CT and acquiring the grayscale values ​​of the multi-layer cross-sectional bone images scanned by the CT machine, a three-dimensional image of the cancellous bone can be obtained. Scanning the cancellous bone based on micro CT can obtain the density distribution information of the bone in space at the micron level.

[0029] Step S102: determining the location of the cavity in the cancellous bone according to the gray value of each point in the three-dimensional image.

[0030] Each point in a three-dimensional image has a corresponding grayscale value, and the size of the grayscale value reflects the size distribution of the density. Figure 1 Schematic diagram of a point set reflecting the location of cancellous bone cavities in an embodiment of the present invention. Figure 1As shown, the white highlighted part represents the high-density trabecular structure, and the gray part represents the low-density soft tissue or tissue fluid (cavity). Therefore, in an optional embodiment, the location of the cavity of the cancellous bone is determined according to the gray value of each point in the three-dimensional image, including: determining the minimum value point of the gray value of each point according to the gray value of each point in the three-dimensional image; and using the minimum value point as the cavity position of the cancellous bone. The distribution of the minimum value points of the gray value of the micro-CT in space can be identified by a computer algorithm to determine the cavity part of the trabecular bone.

[0031] Step S103: Generate a trabecular porous structure model based on the Voronoi (Thyssen polygon) algorithm according to the position of the cavities.

[0032] The Voronoi algorithm divides the space into n polyhedrons according to the seed point set (n seed points) distributed in a given space, each polyhedron contains a seed point, and all points in the polyhedron space are closer to the seed point than to other seed points; the edges of each polyhedron are extracted and thickened to generate a Voronoi three-dimensional solid model. The present invention uses each hole position as a seed point and generates a Voronoi three-dimensional solid model based on the Voronoi algorithm, that is, a trabecular porous structure model.

[0033] After scanning and obtaining a three-dimensional image of cancellous bone, the point set of the cavity position is generated from the three-dimensional space of micro-CT, and the Voronoi algorithm is also performed in the three-dimensional space. Figure 2 The schematic diagram of the Voronoi trabecular bone structure topology framework generated according to the point set of the cavity position in the embodiment of the present invention is shown. The trabecular bone structure generated by this method is not completely the same as the real bone microstructure, but the density information of the uneven distribution of bones is retained.

[0034] Figure 4 and Figure 5 A schematic diagram showing the direct remodeling of the porous structure of trabecular bone based on micro-CT, wherein: Figure 4 This is a schematic diagram of a layer in a microscopic scan of the human trabecular bone structure. Figure 5It is a schematic diagram of a three-dimensional model of trabecular structure obtained by direct remodeling based on micro-CT. This three-dimensional model can be a file in a format such as stl (Standard Template Library), which can be analyzed, optimized or directly manufactured. Depending on the manufacturing process, the scale of this three-dimensional model can be appropriately scaled. This structure completely replicates the microstructural morphology of the bone. Compared with the method of directly remodeling the porous structure of trabecular bone based on micro-CT, the embodiment of the present invention generates a trabecular porous structure model based on the position of the cavities and based on the Voronoi algorithm, which is more flexible and versatile, and can efficiently process and retain the most important information of the bone (bone microstructure and bone density, etc.) in the artificial trabecular bone structure.

[0035] The present invention scans cancellous bone based on micro-CT, and can obtain the density distribution information of bones in space on a micron scale. According to the position of the holes and based on the Voronoi algorithm, a trabecular porous structure model is generated, which can not only retain the important information of the bone in the trabecular porous structure, but also has flexibility and versatility. The trabecular porous structure model of the embodiment of the present invention can reproduce the microstructure, density distribution, mass transfer characteristics and biological properties of the bone. The rigidity of the trabecular porous structure can reach the state of matching cancellous bone, avoiding stress shielding, and the optimized pore size and topological structure can create a good environment for bone growth. The trabecular porous structure prepared by the embodiment of the present invention can be used as various orthopedic implants to improve the comprehensive performance of the product.

[0036] According to a second aspect of an embodiment of the present invention, there is provided a method for preparing a trabecular porous structure based on cancellous bone micro-CT, comprising: generating a trabecular porous structure model using the method provided in the first aspect of an embodiment of the present invention; and printing the trabecular porous structure model using an additive manufacturing method to obtain a trabecular porous structure.

[0037] Additive manufacturing (3D printing) is a manufacturing method with high flexibility and good compatibility with complex shapes, which can realize the manufacturing of the artificial trabecular bone structure in the present invention. By printing the trabecular bone porous structure model by additive manufacturing, parts of any shape can be directly generated from computer graphics data without mechanical processing or any molds, thereby greatly shortening the product development cycle, improving productivity and reducing production costs.

[0038] The printing material can be a metal material with good biocompatibility, such as titanium alloy, tantalum alloy, cobalt-chromium alloy, 316L stainless steel, etc., or ceramics, polymers and composite materials (such as carbon fiber, concrete, nylon, etc.) can be selected according to different purposes. With the selection of different materials, the printing process that can be used can be powder bed fusion process, fused deposition manufacturing process, light curing process, etc.

[0039] The trabecular porous structure obtained in the embodiment of the present invention is a bionic structure with the microstructural characteristics of cancellous bone. This structure can reproduce the microstructure, density distribution, mass transfer characteristics and biological properties of bones, and has good mechanical properties and bone ingrowth performance. The rigidity of the trabecular porous structure can reach the state of matching cancellous bone, avoiding stress shielding, and the optimized pore size and topological structure can create a good environment for bone ingrowth. The trabecular porous structure obtained in the embodiment of the present invention can be used as various orthopedic implants to improve the comprehensive performance of the product.

[0040] According to a third aspect of the embodiments of the present invention, there is provided a trabecular porous structure obtained by the method according to the second aspect of the embodiments of the present invention.

[0041] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions may occur depending on design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for generating a trabecular porous structure model based on cancellous bone micro-CT, characterized in that: include: Scan the cancellous bone based on micro-CT to obtain a three-dimensional image of the cancellous bone; Determine the minimum value point of the gray value of each point according to the gray value of each point in the three-dimensional image, and use the minimum value point as the cavity position of the cancellous bone; According to the hole positions, a trabecular porous structure model is generated based on the Voronoi algorithm; wherein, each hole position is used as a seed point, and the Voronoi algorithm divides the space into n polyhedrons according to a seed point set distributed in a given space, the seed point set has n seed points, each of the polyhedrons contains a seed point, and all points in each of the polyhedrons are closer to the seed point than to other seed points in the seed point set; the edges of each polyhedron are extracted and thickened to generate the trabecular porous structure model.

2. A method for preparing a trabecular porous structure based on cancellous bone micro-CT, characterized in that: include: The method of claim 1 is used to generate a trabecular porous structure model; The trabecular porous structure model is printed by additive manufacturing to obtain the trabecular porous structure.

3. The method according to claim 2, characterized in that The material used for printing the trabecular porous structure model is: ceramic, polymer, or composite material.

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