Two-Dimensional X-Ray Angiography to Examine Fine Vascular Structure Using a Silicone Rubber Injection Compound
Summary
This study presents a simple two-dimensional angiographic method to examine fine vascular structures using a silicone rubber injection compound and soft tissue X-ray system.
Abstract
Angiography is an essential tool for the study of vascular structures in various research fields. The aim of this study is to introduce a simple angiographic method for examining the fine vascular structure of unfixed, fresh tissue using a silicone rubber injection compound and soft tissue X-ray system. This study is especially focused on flap territories used in reconstructive surgery. This study employs angiography with a silicone rubber injection compound in various experimental conditions using Sprague-Dawley rats. First, 15 mL of MV compound and 15 mL of diluent is mixed. Then, 1.5 mL of the curing agent is prepared, and a 24G catheter is cannulated in the common carotid artery of the rat. A three-way stopcock is then connected to a catheter, and the radiopaque agent, after being mixed with the prepared curing agent, is injected immediately without spillage. Finally, as the agent solidifies, the specimen is harvested, and an angiographic image is obtained using a soft tissue X-ray system. This method indicates that high-quality angiography showing fine vascular structures can be easily and simply obtained within in a short period of time.
Introduction
Examining vascular structures such as arteries and veins is an important area of interest, particularly in reconstructive surgery. In this field, flap surgery is widely performed. Therefore, angiographic imaging is actively used to study the flap territory, angiosome, and vascular supply of fresh tissue1. Specifically, there have been continuous efforts to observe the fine vasculature, including fine vessels such as perforators (vessels emerging from deep vessels reaching the skin), and choke vessels (connecting vessels between adjacent angiosomes)2. These two types of vessels are important in the perforator flap reconstruction field and are the main focus of the research3,4.
Various materials are used in angiography. First, there is India ink, which is helpful in observing the gross anatomy of blood vessels. However, it is radiolucent, so angiographic images cannot be obtained. The more commonly-used radiopaque materials are lead oxide and barium. However, toxicity is a crucial drawback of lead oxide, and it is inconvenient to use when mixed with water because of its powdered form. Barium is free from toxicity; however, it is not very feasible, as it should be used after dilution. Both of these radiopaque materials cannot cross capillaries; therefore, if a whole vascular structure must be analyzed, it is necessary to inject them into the artery and vein separately5. In addition, the two materials cause dye leakage during anatomical dissection, so they should be combined with gelatin. Lead oxide-gelatin and barium-gelatin mixtures take at least one day to solidify1,6,7.
Computed tomography (CT) angiography is another widely-used method and can aid in viewing three-dimensional (3D) structures8. However, veins cannot be visualized effectively5. In this modality, clear visualization of the fine vasculature such as choke veins is difficult, except when using specific equipment. The need for more expensive equipment can be a disadvantage, so CT angiography cannot be utilized in all laboratories. By contrast, the soft tissue X-ray system is relatively cheap and can operate more easily. This system is optimal for viewing soft tissues and can provide higher quality soft tissue images than the simple X-ray system. Although the soft tissue X-ray system itself cannot show 3D images, it can help visualize fine vascular structures more clearly than CT angiography. Therefore, we have used the soft tissue X-ray system in many experiments, particularly in various flap models and basic anatomy2,9.
Finally, the use of silicone rubber injection compound angiography has numerous advantages. Because various color agents are prepared, it can be injected and display distinguishable colors such as India ink. Therefore, simultaneously studying the gross anatomy and angiography is possible. It can both pass through capillaries and allow veins to be visualized, making examinations of fine vascular structures possible. Unlike the gelatin mixture, the silicone rubber injection compound solidifies within a short time period, approximately 15 minutes, without any additional procedures. The entire process is summarized in the schematic image in Figure 1.
Protocol
Representative Results
Discussion
Silicone rubber injection compound angiography can be performed easily, does not require expensive equipment, and offers many advantages. In contrast to the preoperative and intraoperative evaluations of patients, experiments using animals and cadavers can provide details on specific conditions, enabling more diverse and in-depth studies. The flap model using rats is particularly valuable to clinicians because changes in various contexts can be observed before clinical applications6,<su…
Divulgaciones
The authors have nothing to disclose.
Acknowledgements
This work (2017R1A2B1006403) was supported by the Mid-Career Researcher Program through a National Research Foundation grant funded by the Korean government (Ministry of Science and ICT).
Materials
| MICROFIL Silicone Rubber Injection Compounds | Flow Tech Inc. | MV-112 | White color agent |
| MICROFIL Silicone Rubber Injection Compounds | Flow Tech Inc. | MV-117 | Orange color agent |
| MICROFIL Silicone Rubber Injection Compounds | Flow Tech Inc. | MV-120 | Blue color agent |
| MICROFIL Silicone Rubber Injection Compounds | Flow Tech Inc. | MV-122 | Yellow color agent |
| MICROFIL Silicone Rubber Injection Compounds | Flow Tech Inc. | MV-130 | Red color agent |
| MICROFIL Silicone Rubber Injection Compounds | Flow Tech Inc. | MV-132 | Clear agent |
| MICROFIL Silicone Rubber Injection Compounds | Flow Tech Inc. | MV-Diluent | Diluent |
| MICROFIL CP-101 For Cast Corrosion Preparations | Flow Tech Inc. | CP-101 | Curing agent |
| SOFTEX X-ray film photographing inspection equipment | SOFTEX | CMB-2 | Soft tissue x-ray system |
| Film | Fujifilm | Industrial X-ray Film (FR 12×16.5cm) | |
| Automatic Development Machine | Fujifilm | FPM 2800 | |
| Rat | Sprague-Dawley rat weighing 200-250 g | ||
| Three-way stopcock | |||
| 24-guage catheter | |||
| Image J | National Institutes of Health | https://imagej.nih.gov/ij/ |
Referencias
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