Special-shaped part ultrasonic three-dimensional imaging system

Abstract

The invention discloses an ultrasonic 3D imaging system based on a complex special-shaped surface, and provides a preparation method of a moldable gel medium as an ultrasonic solid coupling material. According to the main idea of the invention, the gel medium is shaped into a cavity polyhedral module according to the needs of the actual special-shaped part, so that the complex surface of the special-shaped part is changed into a plane, and a necessary premise is provided for realizing ultrasonic automatic plane scanning. By means of program-controlled automatic scanning path planning, the ultrasonic imaging mode is changed from manual operation to automatic operation, experience dependence on ultrasonic scanners can be remarkably reduced, ultrasonic scanning is standardized and automatic, and the problem of individual difference during ultrasonic manual scanning of different scanners is solved. The prepared moldable gel medium has excellent sound transmission performance and mechanical strength, good biocompatibility and smooth surface, and is convenient for ultrasonic scanning.

Description

Technical Field

[0001] The present invention relates to an ultrasonic imaging system for atypical parts, including the preparation of an elastic gel medium, an automatic scanning device and a 3D reconstruction method, and belongs to the technical field of ultrasonic imaging detection, equipment design and hydrogel functional materials. Background Art

[0002] Ultrasound imaging has been widely used in the field of medical imaging due to its advantages such as non-invasiveness, no radiation, low cost and easy operation. It has developed into the main means of imaging multiple organs such as abdomen, heart, blood vessels, obstetrics and gynecology, musculoskeletal system, etc.

[0003] During ultrasound imaging, coupling agents play an important role in impedance matching. Coupling agents can fill the air gap between the probe and the skin, allowing ultrasound waves to be more effectively transmitted into the tissue, increasing the strength of the echo signal and image clarity. However, when performing 3D ultrasound imaging of complex and irregular surfaces, especially curved parts such as the Achilles tendon, elbows, and hands, or parts of the body that are affected by deformation, such as breast tissue, it will bring challenges to scanning and 3D reconstruction. Summary of the invention

[0004] In view of the above problems, the present invention discloses an ultrasonic 3D imaging system based on complex and irregular surfaces, and provides a method for preparing a plastic gel medium as an ultrasonic solid coupling material. First, an elastic gel medium is used as a solid coupling agent for ultrasound to solve the disadvantage that liquid coupling agents on the market are generally not easy to image on complex surfaces. The design concept of planarizing complex surfaces, that is, "simplifying the complex and making the curve straight", has a clear positive significance for ultrasonic 3D imaging. Furthermore, the present invention introduces elastic gel, which is more convenient for fitting different irregular surfaces. Finally, the program-controlled automatic scanning path planning transforms the ultrasonic imaging mode from manual to automatic, which can significantly reduce the dependence on the experience of ultrasonic scanners and largely avoid the differences between different scanners. For example, in ultrasonic breast tissue examination, patients often adopt a lying posture, and the external pressure of the ultrasonic probe often causes uncertain local deformation of the breast tissue, resulting in unstable ultrasonic imaging results. The method provided by the present invention can not only use a convenient in-place posture for automated scanning and 3D imaging, but also free ultrasonic doctors from the complex scanning work of irregular surfaces.

[0005] In short, the main idea of ​​the present invention is to shape the gel medium into a hollow polyhedron module according to the needs of the actual irregular parts, and then transform the complex surface of the irregular parts into a plane, which provides the necessary premise for realizing automatic planar scanning of ultrasound. Finally, the 3D image can be automatically reconstructed after simple splicing. The core value of the present invention lies in taking a different approach, solving the problem that rigid ultrasonic probes are not convenient for scanning on complex irregular surfaces, and realizing automatic scanning and generation of 3D ultrasonic images. The present invention provides a tool with clear practical value for ultrasonic scanning and image reconstruction of irregular parts. In fact, the present invention is not only applicable to ultrasonic scanning and 3D reconstruction of irregular parts of living bodies, but also to internal ultrasonic detection of complex non-living objects.

[0006] The key innovation of the present invention is that the elastic gel acting as a coupling agent is prepared into a cavity polyhedron module A, that is, the outside of the special-shaped structure is wrapped with an elastic gel medium that fits tightly therewith, and the outer surface of the elastic gel is constrained to be a plane by an external mold.

[0007] The hollow polyhedron module A is constructed by the inner mold A1 of the standard special-shaped part and the outer mold A2 of the polyhedron; the inner mold A1 of the standard special-shaped part is a typical special-shaped part mold constructed in advance, such as standard hand, foot, and joint molds of different sizes. The process of preparing the hollow polyhedron module A is: first pour the prepared gel medium liquid material into the customized polyhedron outer mold A2, then immerse the inner mold A1 of the special-shaped part into the gel medium solution, and then add a cross-linking agent or use the heating method to fix it.

[0008] Among them, the size of the customized polyhedron outer mold A2 is freely customized according to the different positions to be collected. In medical examinations, models of corresponding shapes will be selected, such as breasts, feet, elbows, necks, etc. The internal size of the polyhedron outer mold A2 needs to be larger than and able to accommodate the entire inner mold A1, and the bottom of the open outer mold A2 needs to be sealed and cannot leak. The distance between the outer surface of the complex and irregular parts to be tested and the outer surface of the polyhedron module A is between 2-4cm to facilitate ultrasound imaging scanning.

[0009] Among them, the elastic gel medium is prepared from an aqueous solution of a polymer monomer and a cross-linking agent. The polymer monomer can be selected from one or more of chitosan, acrylic acid, acrylate, agarose, gelatin acrylate, polyurethane, polylatex, acrylic acid, methacrylic acid, acrylamide, vinyl methacrylate, N-isopropylacrylamide, N,N-methylenebisacrylamide, polydimethylsiloxane, sodium alginate or polyacrylamide; the cross-linking agent can be selected from one or more of divinylbenzene, diisocyanate, ethylene glycol diacrylate, diethylenediamine, methacrylamide, N,N'-diethylaminotoluene, ammonium persulfate, N,N,N',N'-tetramethylethylenediamine.

[0010] The polymer monomer of the gel material for preparing the cavity polyhedron module A is 1%-20% by mass, the cross-linking agent is 0.1%-10% by mass, and the deionized water is 0.1%-99% by mass. The gel medium liquid material is formed by uniformly mixing the polymer monomer, the cross-linking agent, the deionized water and other materials, including but not limited to mechanical stirring, magnetic stirring, ultrasonic vibration and other stirring measures.

[0011] Furthermore, the uniformly mixed gel medium liquid material needs to be degassed. This includes vacuum degassing, with a vacuum degree of 0.01MPa~-0.1MPa and a degassing time of 1-600 minutes. This includes ultrasonic degassing, which generates a large number of tiny cavitation bubbles by generating high-frequency vibrations in the liquid. These bubbles then collapse rapidly, releasing a large amount of energy to help remove the gas, with an acoustic intensity ranging from 0.1W / cm² to 10W / cm².

[0012] After degassing, the liquid is slowly poured into the outer mold A2, and the gel material is solidified by adding a cross-linking agent or heating. If heating is used, the temperature can be controlled between 30-75°C.

[0013] The prepared cavity polyhedron module A has a multi-plane structure composed of multiple rectangular blocks. The interior is a complex and irregular part to be tested. When the irregular part, such as the foot, extends into the internal cavity of the cavity polyhedron A, the complex and irregular part needs to fit tightly with the interior of the cavity polyhedron module A, and no air can be retained. Eliminating the air remaining on the contact surface is conducive to obtaining a good quality ultrasound image. In order to make the fit tight, the complex and irregular mold can be slightly smaller than the irregular part or object to be tested, and the elastic deformation of the gel medium in the cavity polyhedron A can be controlled at 5%-10%.

[0014] The ultrasonic scanning module B is composed of an ultrasonic probe B1, a scanning frame B2, a control system B3, and an ultrasonic imaging module B4.

[0015] The ultrasonic probe B1 and the scanning frame B2 are detachably connected, the shapes of the fixing component and the ultrasonic probe need to match, and an annular groove is designed on the fixing component to be snap-connected with the ultrasonic probe B1.

[0016] Furthermore, the scanning frame B2 must ensure that the accuracy of the movable range of the ultrasonic probe B1 is between 5-200 microns.

[0017] Furthermore, the control system B3 is controlled by a computer, and the control system B3 needs to accurately control the range of motion of the scanning frame with an accuracy between 5-200 microns.

[0018] Furthermore, the control system B3 can use the photographs of the outer surface of the module A to automatically calculate the positioning position according to the stereoscopic vision algorithm, and control the moving trajectory of the scanning frame B2 according to the calculated position.

[0019] Furthermore, the scanning frame B2 is controlled by a motor, which may be a linear motor or a stepping motor.

[0020] The reconstruction module C is characterized in that, based on the automatic scanning results covering multiple rectangular blocks, the overall 3D reconstructed image of the heteromorphic part is completed according to the strategy of separately reconstructing the blocks and then splicing them.

[0021] Furthermore, the reconstruction module can reconstruct 3D images of human body parts such as blood vessels and soft tissues, and can also reconstruct 3D images of the interior of complex objects.

[0022] Furthermore, the imaging of human body parts can be a 3D structural image or a 3D blood flow image.

[0023] Furthermore, based on the collected ultrasound video data, the reconstruction module needs to divide the video into 1-30 pictures per second, and then reconstruct the 3D image based on the pictures.

[0024] Beneficial effects of the present invention:

[0025] 1) From the perspective of materials science, the gel medium prepared by the above method has good acoustic conductivity, and its sound velocity is close to that of water, between 1500-1700m / s. It also has good stretchability, which can reach 5%-10%. It becomes a very good acoustic impedance matching and conductive medium material. The planarization of special-shaped parts can greatly improve the efficiency of standardized and automated scanning and 3D reconstruction of parts with complex surfaces such as feet, hands, breasts, necks, etc.

[0026] 2) In terms of ease of operation, the ultrasonic scanning module B scans horizontally or vertically along the external plane of the cavity polyhedron A in a single path, and can automatically calculate the scanning path. This scanning method can avoid repeated pressure and manual errors caused by ultrasonic inspectors when scanning complex surfaces. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a schematic diagram showing a 3D ultrasound imaging system of the present invention;

[0028] Figure 2 is a schematic diagram of a 3D imaging system for a foot and Achilles tendon according to Embodiment 1 of the present invention;

[0029] Figure 3 This is the ultrasonic 3D reconstructed image result of the foot and Achilles tendon described in Example 1 of the present invention. DETAILED DESCRIPTION

[0030] The present invention is further described below in conjunction with specific examples. It should be understood that the examples listed are only used to explain the present invention rather than to limit the scope of the present invention.

[0031] Example 1

[0032] As a specific implementation of the present invention, this embodiment selects a foot with a complex surface and an Achilles tendon for 3D ultrasonic imaging. A healthy volunteer is selected, and a foot model is performed according to the actual size to prepare a foot inner mold A1 made of plastic material.

[0033] According to the size of the foot, a distance of 2 cm is reserved at the top and bottom, front and back, left and right of the foot, and a polyhedral outer mold A2 suitable for a combination of two rectangular blocks is prepared. The outer mold material is an acrylic plate.

[0034] Then prepare the liquid material of the gel medium, add deionized water, acrylamide, N,N-methylbisacrylamide, ammonium persulfate, and add them to the beaker in a mass ratio of 86%, 13%, 0.01%, and 0.5%, respectively, and stir evenly for 30 minutes at a magnetic stirring speed of 1000 rpm. Then add N,N,N',N'-tetramethylethylenediamine with a mass ratio of 0.49%, continue stirring for 1 minute, and ultrasonic degassing for 1 minute. Then slowly pour the elastic material liquid into the polyhedral outer mold A2. Immerse the plastic foot mold A2 in the liquid material of the gel medium, keeping it as centered as possible up and down, front and back, and left and right. Wait for 1 hour at room temperature, and the elastic material condenses from liquid to solid. Then extract the foot model to make a cavity polyhedron module A that can be placed in the volunteer's foot.

[0035] Then build a scanning system, such as Figure 2 As shown, the scanning frame is driven by a stepper motor and a lead screw shaft to ensure that the ultrasound probe B1 can scan from the foot to the leg along the Achilles tendon at a speed of 2 mm per second.

[0036] Figure 3 The reconstructed ultrasonic 3D image of the foot and Achilles tendon can clearly show the condition of the entire Achilles tendon of a healthy volunteer.

[0037] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Based on the present invention, some modifications or improvements can be made thereto, including combining various technical features in any other suitable manner, and these simple variations and combinations should also be regarded as the contents disclosed by the present invention. Therefore, these modifications or improvements made on the basis of not departing from the spirit of the present invention all belong to the protection scope of the present invention.

Claims

1. An ultrasonic three-dimensional imaging system for abnormally shaped parts, characterized in that: It consists of a cavity polyhedron module A containing an elastic gel medium, an ultrasonic scanning module B, and a three-dimensional image reconstruction module C for the deformed part; wherein module A acts as an ultrasonic coupling medium, and module A is composed of a plurality of hollow cuboids. After the deformed part to be measured is placed in the cavity, the surfaces of the two are tightly fitted together to form a plurality of cuboid structures; then the ultrasonic scanning module B and the three-dimensional image reconstruction module C for the deformed part are responsible for two-dimensional ultrasonic imaging and three-dimensional image reconstruction of the deformed part respectively; module B is responsible for automatically scanning along the outer surfaces of the plurality of cuboid structures to obtain a plurality of sets of ultrasonic two-dimensional image sequences, wherein each set of ultrasonic two-dimensional images corresponds to a cuboid structure; module C is responsible for reconstructing the plurality of sets of ultrasonic two-dimensional images in blocks according to the corresponding cuboid structures, and finally splicing them into an ultrasonic three-dimensional image of the entire deformed part.

2. The polyhedral module A according to claim 1, characterized in that: A gel medium is filled between the outer surface of the polyhedron and the cavity part, and the gel medium has a tensile deformation of 5%-10%; the gel medium is composed of a polymerized monomer and a cross-linking agent; the preparation process of the elastic gel medium is completed by two steps of degassing and polymerization; wherein, degassing is completed by an ultrasonic method under quasi-vacuum conditions; polymerization is achieved by adding a cross-linking agent or by a temperature control method; the cavity polyhedron module A is prepared by an inner mold A1 of a standard special-shaped part and an outer mold A2 of a polyhedron, and the specific preparation steps are: the gel medium is poured between the inner mold A1 of a standard special-shaped part and the outer mold A2 of a polyhedron, and after shaping, the inner mold A1 of the standard special-shaped part is taken out to form a cavity polyhedron module A.

3. The polyhedral module A according to claim 1, characterized in that: The polymerization monomers are composed of one or more of the following: chitosan, acrylate, agarose, gelatin acrylate, polyurethane, polylatex, acrylic acid, methacrylic acid, acrylamide, vinyl methacrylate, N-isopropylacrylamide, N,N-methylenebisacrylamide, polydimethylsiloxane, sodium alginate or polyacrylamide; the crosslinking agent is composed of divinylbenzene, diisocyanate, ethylene glycol diacrylate, diethylenediamine, methacrylamide, N,N'-diethylaminotoluene, ammonium persulfate, N,N,N',N'-tetramethylethylenediamine.

4. The ultrasonic scanning module B according to claim 1, characterized in that: It consists of an ultrasonic probe B1, a scanning frame B2, a control system B3 and an ultrasonic imaging module B4; the ultrasonic probe B1 is rigidly constrained on the scanning frame B2; the control system B3 is responsible for automatically controlling the scanning frame B2, so that the ultrasonic probe B1 can automatically traverse the outer surface of the module A; the ultrasonic imaging module B4 scans each rectangular structure separately to obtain a corresponding set of ultrasonic two-dimensional images, and obtains multiple sets of ultrasonic two-dimensional images after the scanning is completed.

5. The three-dimensional image reconstruction module C for the irregular part according to claim 1, characterized in that: Based on the multiple sets of ultrasonic two-dimensional images obtained, the strategy of reconstructing the blocks separately and then splicing them is followed. That is, the three-dimensional image of each rectangular area is first reconstructed separately, and then the three-dimensional images of all the rectangular areas are spliced ​​together to finally construct an overall three-dimensional image of the abnormal part.

6. The ultrasonic scanning module B as claimed in claim 4, characterized in that: The scanning frame B2 is composed of a motor, a movable rod and a fixed frame; the motor drives the screw module to control the uniaxial movement of the slide, and the surface of the slide is connected to a mechanical clamping structure for fixing the ultrasonic probe; preferably, the movement rate of the ultrasonic probe B1 is 0.2-5cm / s.

7. The ultrasonic scanning module B as claimed in claim 4, characterized in that: Based on multiple shots of the outer surface of module A, the control system B3 uses the principle of stereoscopic vision to calculate the external three-dimensional shape of module A, and then automatically plans a scanning path for each independent cuboid, and uses the motor-driven screw module described in the scanning frame B2 to achieve fully automatic scanning along the outer surface of module A in sequence.

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