Self-solidifying composite material for improving CTA image quality of in-vitro placenta tissue as well as preparation method and application of self-solidifying composite material

Abstract

The invention provides a self-solidifying composite material for improving in-vitro placenta tissue CTA image quality. The self-solidifying composite material comprises a solvent, denture powder, barium sulfate and a pigment, the solvent is formed by mixing dibutyl phthalate and denture water according to the volume ratio of 1: (2.5-3.0); each milliliter of the solvent contains 0.50-0.55 g of denture powder, 0.030-0.04 g of barium sulfate and 0.3-0.6 g of pigment, in-vitro placenta tissue is subjected to perfusion casting and CTA contrast analysis through the self-solidifying composite material provided by the invention, the result shows that the self-solidifying composite material provided by the invention has high density and excellent imaging contrast effect, and the materials are easy to obtain, low in cost, simple to operate and suitable for industrial production. Due to the excellent imaging effect and the convenient operation process, the method has a wide application prospect in biomedical research and clinical diagnosis.

Description

Technical Field

[0001] The present invention belongs to the field of medicine and CTA imaging technology, and specifically relates to a self-curing composite material for improving the CTA imaging quality of ex vivo placental tissue, and a preparation method and application thereof. Background Art

[0002] As an important organ connecting the fetus and the mother, the placenta is responsible for the exchange of nutrients and oxygen, and removes metabolic waste from the fetus. The study of the structure and blood vessels of the placenta after ex vivo treatment is of great significance for understanding the effects of fetal development, pregnancy complications and maternal diseases on placental function, thereby improving diagnostic and treatment strategies. At present, ultrasound and magnetic resonance imaging are mainly used for placental blood flow imaging. Although these methods have the advantages of real-time, non-invasive and safe, their resolution and field of view are limited and cannot provide sufficiently detailed vascular structure information. CT angiography (CTA) has the advantages of high resolution and rapid imaging in blood flow imaging, which can accurately display the structure of arteries and veins and provide three-dimensional images. However, due to its invasiveness and radioactivity, it is difficult to apply it to the study of placental blood vessels in pregnant women, and it is difficult to obtain high-quality CTA images of ex vivo placental tissue due to the lack of physiological blood flow. This limits the application and reference value of CTA in placental blood flow research.

[0003] Although the traditional barium sulfate perfusion technology can enhance the CT imaging effect of ex vivo tissue, there are problems such as uneven perfusion and unsatisfactory imaging effect in practical applications. The ex vivo tissue uses a channel casting specimen made of self-curing material to well display the course of blood vessels in the tissue. However, how to further optimize the perfusion materials and methods to improve the image quality is still an urgent problem to be solved.

[0004] Chinese patent CN109540936A describes a room temperature contrast agent using a carboxymethyl cellulose barium sulfate suspension, with a barium sulfate concentration of 10-40% and a carboxymethyl cellulose concentration of 0.05%. Carboxymethyl cellulose, as a thickener, does not solidify, but only increases the viscosity of the solution, cannot quickly harden and set, and the operation process has high environmental requirements. Chinese patent CN203898491U uses a mixture of barium sulfate solution and gelatin. Gelatin has good flexibility, and this combination can enhance the imaging quality of microvessels, but the gelatin solution needs to be heated and dissolved before it can be used for mold perfusion, and it is not as good as the self-condensing barium sulfate composite material of the present invention in terms of solidification time and fluidity, and is only suitable for molds that require longer operation time and flexibility. The self-condensing tooth tray powder material used in the article "Method for Making Cast Specimens Using Self-condensing Tooth Tray Powder" (Wang Xinghai) will be significantly affected in terms of material fluidity and uniformity, and the final technical effect will be reduced, especially in terms of filling of small blood vessels and imaging clarity. Summary of the invention

[0005] In view of this, the present invention provides a self-curing composite material for improving the CTA image quality of ex vivo placental tissue, and a preparation method and application thereof.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: A self-curing composite material for improving the quality of CTA images of ex vivo placental tissue, the self-curing composite material comprising a solvent, dental tray powder, barium sulfate, and a pigment; the solvent is prepared by mixing dibutyl phthalate and dental tray water in a volume ratio of 1: (2.5-3.0); each milliliter of the solvent contains 0.50-0.55 g of dental tray powder, 0.030-0.04 g of barium sulfate, and 0.3-0.6 g of pigment.

[0007] In some specific embodiments, preferably, the solvent is a mixture of dibutyl phthalate and dental tray water in a volume ratio of 1:2.69; each milliliter of the solvent contains 0.52g of dental tray powder, 0.031g of barium sulfate, and 0.5g of pigment.

[0008] A method for preparing the above-mentioned self-curing composite material includes the following steps: firstly, uniformly mixing tooth tray powder, barium sulfate and pigment, then adding dibutyl phthalate and tooth tray water and stirring, and finally stirring uniformly until no bubbles are generated to obtain the self-curing composite material.

[0009] A method for performing in vitro placental tissue perfusion casting using the self-curing composite material comprises the following steps: S1. Placental specimen processing: Collect normal ex vivo placental tissue from healthy full-term births, clean the placental surface, identify the placental type, observe the damage to the maternal surface of the placenta, and trim the umbilical cord to make it suitable for perfusion operations; S2. Preparation for perfusion: Perform umbilical artery and vein cannulation, and perfuse normal saline into the placental blood vessels through the umbilical artery and vein cannulation until there is no obvious blood stain in the blood vessels to ensure that the blood vessels are clean; S3. Arteriovenous perfusion casting: The prepared self-curing composite material is slowly injected into the placental blood vessels through the umbilical arteriovenous cannula. After the perfusion is completed, the umbilical cord is ligated to prevent the material from flowing back or leaking. The self-curing composite material is waited for to solidify and take shape in the placental blood vessels. The perfusion casting is completed.

[0010] Furthermore, in order to make the self-curing composite material perfused evenly in step S3, during the perfusion process, the placenta is gently massaged to help the composite material be evenly distributed in the blood vessels.

[0011] A CTA angiography method of the perfused cast ex vivo placenta obtained by the above method comprises the following steps: S1. CT scan: Use Siemens go.fit 64-row CT equipment to keep the casted placenta with the fetus facing up and the mother facing down, and spread it out for flat scanning; S2. Image processing: After acquiring the CTA image, three-dimensional reconstruction is performed using software to generate a three-dimensional image of the placental vessels. The image is scored with double-blind visual scoring to evaluate the vascular filling and branch clarity.

[0012] Furthermore, the CT scanning parameters in step S1 are as follows: tube voltage 80 kV, automatic tube current, slice thickness 1.0 cm, slice spacing 0.5 cm, pitch 1.0, 0.80 mm reconstruction.

[0013] Compared with the prior art, the present invention has the following beneficial effects: (1) Barium sulfate in the self-solidifying composite material has high density and excellent imaging contrast effect. In CT scans, barium sulfate can significantly enhance the contrast of blood vessels, making the vascular structure clearer; the mixture of denture powder and dibutyl phthalate makes the material have good fluidity, ensuring that the composite material can evenly fill the blood vessels during the perfusion process, avoiding the image blur caused by uneven perfusion; the addition of denture water allows the composite material to solidify quickly in the blood vessels to form a stable cast, which not only improves the efficiency of the experiment, but also reduces the material reflux or leakage that may occur during the operation.

[0014] (2) The self-curing composite material is easy to obtain, low in cost, and has a simple preparation method, making it suitable for large-scale promotion and application. Compared with other complex placental angiography methods, the operation process of the present invention is simple and easy, does not require special equipment or complex operations, and greatly reduces the threshold for research and clinical application.

[0015] (3) The present invention is not only applicable to the study of ex vivo placental tissue, but can also be extended to the study of vascular imaging of other ex vivo tissues and organs. Its excellent imaging effect and convenient operation process make it have broad application prospects in biomedical research and clinical diagnosis. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a CTA image result diagram of the self-curing composite material with different contents of barium sulfate after injection in Example 1 of the present invention.

[0017] Figure 2 This is a CTA image result diagram of the self-curing composite material after infusion of the formulation No. 4 in Example 1 of the present invention and the self-curing composite material in Comparative Example 2.

[0018] Figure 3 These are CTA imaging results after the self-curing composite materials of Example 1 and Comparative Example 2 of the present invention were poured.

[0019] Figure 4 This is a comparison of the before and after images of the isolated placental tissue perfusion casting. DETAILED DESCRIPTION

[0020] The present invention is further described in detail below in conjunction with specific embodiments so that those skilled in the art can understand the present invention more clearly.

[0021] Sources and physical and chemical parameters of key test materials: Source of ex vivo placenta: The donation agreement was approved by the Ethics Committee of Xiangyang Central Hospital Affiliated to Hubei University of Arts and Sciences; the specimens were donated voluntarily by patients from the Department of Obstetrics and Gynecology of Xiangyang Central Hospital Affiliated to Hubei University of Arts and Sciences.

[0022] Example 1 This embodiment provides a self-curing composite material for improving the CTA image quality of ex vivo placental tissue and a preparation method thereof, and CTA angiography of an ex vivo placenta perfusion mold and the perfusion mold using the self-curing composite material, as follows: 1. Self-curing composite material and preparation method thereof: The specific material ratio is shown in Table 1 below: Table 1 Details of materials of self-curing composite materials

[0023] Take the dental tray powder, barium sulfate and pigment in sequence according to the serial numbers in the table and mix them evenly; then slowly add 13 mL of dibutyl phthalate and 35 mL of dental tray water while stirring; finally, ensure that the mixture remains uniform and free of bubbles, and 5 different self-curing composite materials are obtained.

[0024] 2. Perfusion casting of isolated placental tissue: S1. Placental specimen processing: Collect normal ex vivo placental tissue from healthy full-term births, clean the placental surface, identify the placental type, observe the damage to the maternal surface of the placenta, and trim the umbilical cord to make it suitable for perfusion operations; S2. Preparation for perfusion: Perform umbilical artery and vein cannulation, and perfuse normal saline into the placental blood vessels through the umbilical artery and vein cannulation until there is no obvious blood stain in the blood vessels to ensure that the blood vessels are clean; S3. Arteriovenous perfusion casting: The prepared self-curing composite material is slowly injected into the placental blood vessels through the umbilical arteriovenous catheter. During the perfusion process, gently massage the placenta to help the composite material be evenly distributed in the blood vessels. After the perfusion is completed, the umbilical cord is ligated to prevent material reflux or leakage, and the self-curing composite material is waited for to solidify and take shape in the placental blood vessels. The perfusion casting is completed.

[0025] 3. CTA angiography of perfused cast isolated placenta: S1. CT scan: Siemens go.fit 64-row CT equipment was used to keep the cast placenta with the fetus facing up and the mother facing down, and spread it out for flat scanning. The CT scanning parameters were as follows: tube voltage 80kV, automatic tube current, slice thickness 1.0cm, slice spacing 0.5cm, pitch 1.0, 0.80mm reconstruction.

[0026] S2. Image processing: After acquiring the CTA image, the software is used for three-dimensional reconstruction to generate a three-dimensional image of the placental blood vessels, and the image is scored by double-blind visual evaluation to evaluate the vascular filling and branch clarity. The double-blind visual scoring criteria are shown in Table 2 below.

[0027] Table 2 Scoring criteria for placental tissue CTA images

[0028] Specific visual scoring method: Two radiologists with rich diagnostic experience independently reviewed the CTA images without knowing the tissue information. If there was a disagreement, the final result was determined through discussion.

[0029] Comparative Example 1 This embodiment provides a composite material and a preparation method thereof, and the composite material for ex vivo placental perfusion casting and CTA angiography after the perfusion casting. The steps and methods are basically the same as those in Example 1, except that: the composite material lacks dibutyl phthalate compared to the formula No. 4 in Example 1, and the rest remains unchanged.

[0030] Comparative Example 2 This embodiment provides a traditional contrast agent and a contrast method thereof, and the steps and methods thereof are substantially the same as those of Embodiment 1, except that the traditional contrast method uses 5% ioversol liquid contrast agent to be directly injected into the placental umbilical artery and umbilical vein for perfusion casting, and the rest remain unchanged.

[0031] Furthermore, in order to understand the final results of the above embodiments and comparative examples, the following analysis was also performed: Statistical analysis was performed using GraphPad Prism 8 software. First, descriptive statistical analysis was performed on the data of the material solidification time, and the D'Agostino & Pearson test method was used for normality test to ensure that the data conformed to the normal distribution. Subsequently, the unpaired t-test was used to analyze the difference of the data. The "*" in the results indicates P < 0.05, indicating that the difference is statistically significant.

[0032] For visual scoring data, the data were ordered categorical data. The differences between two groups of data were analyzed using the Mann-Whitney U test for nonparametric analysis; the differences between three or more groups of data were analyzed using the Kruskal-Wallis H test for nonparametric analysis. In the results, "*" means P < 0.05, indicating that the difference is statistically significant, and "ns" means that there is no significant statistical difference.

[0033] Figure 1This is a graph showing the effect of different barium sulfate contents on CTA images after composite material perfusion in Example 1. It can be seen from the figure that: with the increase of barium sulfate content, the visual score gradually increases. When there is no barium sulfate, the blood vessels and branches are almost invisible. When the barium sulfate content is 1.5g, the perfusion material can clearly show the primary, secondary and tertiary branches of the placental blood vessels; and the filling effect is better.

[0034] Figure 2 The figure is a result diagram of the effect of the addition of dibutyl phthalate on the CTA image and the solidification time of the composite material after casting. It can be seen from the figure that dibutyl phthalate can significantly increase the clarity of the CTA image showing the placental vascular branches after casting (AB). In addition, dibutyl phthalate significantly increases the solidification time of the cast composite material (C).

[0035] Figure 3 This is a comparison result diagram of CTA images under the sequence number 4 formulation in Example 1 and the traditional angiography method. It can be seen from the figure that: compared with the traditional angiography method, the self-curing composite material significantly increases the display of placental vascular branches in CTA images and improves the fullness of placental vascular CTA images.

[0036] Figure 4 This is a comparison of the effects of the self-curing composite material provided by the present application before and after perfusion casting of the ex vivo placental tissue. The figure shows the general view of the placenta before and after casting (AB). The picture after casting shows that the casting agent fills the placental blood vessels well, and clearly shows the vascular branches and lobule distribution of the placental tissue (B).

[0037] The specific raw materials not described in the present invention are all existing materials and can be directly purchased from the market.

[0038] The above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A self-curing composite material for improving the quality of CTA images of ex vivo placental tissue, characterized in that: The self-curing composite material comprises a solvent, a tooth tray powder, barium sulfate and a pigment; the solvent is prepared by mixing dibutyl phthalate and tooth tray water in a volume ratio of 1: (2.5-3.0); each milliliter of the solvent contains 0.50-0.55 g of tooth tray powder, 0.030-0.04 g of barium sulfate and 0.3-0.6 g of pigment.

2. The self-curing composite material according to claim 1, characterized in that: The solvent is prepared by mixing dibutyl phthalate and dental tray water in a volume ratio of 1:2.69; each milliliter of the solvent contains 0.52g of dental tray powder, 0.031g of barium sulfate and 0.5g of pigment.

3. A method for preparing the self-curing composite material according to claim 1 or 2, characterized in that: The method comprises the following steps: firstly, uniformly mixing tooth tray powder, barium sulfate and pigment, then adding dibutyl phthalate and tooth tray water for stirring, and finally uniformly stirring until no bubbles are generated to obtain a self-curing composite material.

4. A method for performing in vitro placental tissue perfusion casting using the self-curing composite material according to claim 1 or 2, characterized in that: The following steps are involved: S1. Placental specimen processing: Collect normal ex vivo placental tissue from healthy full-term births, clean the placental surface, identify the placental type, observe the damage to the maternal surface of the placenta, and trim the umbilical cord to make it suitable for perfusion operations; S2. Preparation for perfusion: Perform umbilical artery and vein cannulation, and perfuse normal saline into the placental blood vessels through the umbilical artery and vein cannulation until there is no obvious blood stain in the blood vessels to ensure that the blood vessels are clean; S3. Arteriovenous perfusion casting: The prepared self-curing composite material is slowly injected into the placental blood vessels through the umbilical arteriovenous cannula. After the perfusion is completed, the umbilical cord is ligated to prevent the material from flowing back or leaking. The self-curing composite material is waited for to solidify and take shape in the placental blood vessels. The perfusion casting is completed.

5. The method according to claim 4, characterized in that In step S3, in order to make the self-curing composite material perfused evenly, during the perfusion process, the placenta is gently massaged to help the composite material be evenly distributed in the blood vessels.

6. A CTA angiography method of the perfused cast ex vivo placenta obtained by the method of claim 4 or 5, characterized in that: The following steps are involved: S1. CT scan: Use Siemens go.fit 64-row CT equipment to keep the casted placenta with the fetus facing up and the mother facing down, and spread it out for flat scanning; S2. Image processing: After acquiring the CTA image, three-dimensional reconstruction is performed using software to generate a three-dimensional image of the placental vessels. The image is scored with double-blind visual scoring to evaluate the vascular filling and branch clarity.

7. The method according to claim 6, characterized in that The CT scanning parameters in step S1 are as follows: tube voltage 80 kV, automatic tube current, slice thickness 1.0 cm, slice spacing 0.5 cm, pitch 1.0, 0.80 mm reconstruction.

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