On March 12, Professor Wang-Yuhl Oh from the Department of Mechanical Engineering announced that his research team has developed an improved method for optical imaging of the three-dimensional (3D) microstructure of the vessel wall of living animals. Using this new method, the research team successfully acquired high-resolution (with a longitudinal pitch of 34 micrometers (μm) and an axial pitch of 9.2 μm) 3D images of the vessel for the first time in the world.
▲ Professor Wang Yuhl Oh
The newly developed method has high frame-rate, resolution, image quality, and large image acquisition area. In addition to its superior performance, the method supports functional imaging such as polarization-sensitive imaging, which is useful in finding weak spots in the vessel. It is expected that this method will bring breakthroughs in detection and treatment of cardiovascular diseases.
▲ 3D intravascular endoscopy
Conventional devices that are used for diagnosis of cardiovascular diseases relied on intravascular optical coherence tomography (OCT), which provides the highest resolution cross-sectional images of vessels. However, due to its slow image acquisition speed, it allows visualization of only a short segment of the vessel, following proximal balloon occlusion (using a balloon to block the flow of blood) or nonocclusive saline or contrast agent flush (using a clear liquid to remove the blood of the section temporarily).
To overcome this problem, the research team incorporated optical frequency-domain imaging (OFDI), a second-generation OCT technology, into a custom-made, high-speed, and high-resolution imaging catheter with an outer diameter of 0.87 millimeters (mm) and succeeded in acquiring the image of the inner wall of the vessel. They applied this technology in acquiring the intravascular image of a living rabbit’s aorta, which is similar in size with that of humans. They successfully acquired high-resolution images of a 7 centimeter (cm) aorta in 5.8 seconds at a rate of 350 frames per second with pitch ranging from 10 μm to 35 μm in every direction. If the pitch is set to 200 μm, which is the pitch used in commercial intravascular endoscopy systems, the intravascular image of a 7 cm vessel can be acquired in less than one second.
Professor Oh said that the newly developed intravascular endoscopy system has the best performance in the world, and that it is notable since the system was tested on a living animal, which has a similar vessel structure to that of humans. He added that the research team will cooperate with hospitals and plans on testing this system on animal hearts similar to the size of a human heart. In a few years, he hopes to clinically apply this system to patients. The research was supported by the Korea National Research Foundation, and the results were published on the January issue of the journal Biomedical Optics Express
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