| Author: | Xu, Yajie |
| Title: | Characterization of focused intravascular transducer for vulnerable plaque diagnosis |
| Other Title: | Characterization of focused intravascular transducer for vulnerable plaque diagnosis |
| Advisors: | Sun, Lei (BME) |
| Degree: | M.Sc. |
| Year: | 2016 |
| Subject: | Ultrasound transducers. Intravascular ultrasonography. Arteriosclerosis -- diagnosis. Hong Kong Polytechnic University -- Dissertations |
| Department: | Interdisciplinary Division of Biomedical Engineering |
| Pages: | ix, 52 pages : color illustrations |
| Language: | English |
| Abstract: | An estimated more than 19 million people dies annually due to the atherosclerotic cardiovascular disease. Among these deaths, the disease of the arteries accounts for the main part and the formation of a plaque in the walls of arteries could play a key role in risking patient life. In clinical, a life threatening stage of the atherosclerotic cardiovascular disease is the formation of vulnerable plaque which are characterized by large lipid pool, heavy macrophage, thin fibrous collagen-rich cap. Therefore, the vulnerable plaque could rupture easily and lead to inflammation, calcification and hemorrhage. Currently, the artery disease is clinically conducted by the gold standard technique X-Ray angiography. This method can reveal luminal diameter and provide the dimension of stenosis. But this method cannot image the vessel wall and give detailed information about the composition of the atherosclerotic plaque, thus the main features of the atherosclerotic disease such as the lipid rich plaque cannot be seen. Intravascular ultrasound (IVUS) is a new technique to the arterial vascular wall imaging. This technique can execute real-time and direct imaging of the atheroma and give cross-sectional, tomographic perspective of the vessel wall and atherosclerotic disease. In addition, this method can also detect unrecognized disease and uncertain severity of lesions by X-Ray angiography. More importantly, IVUS can delineate the thickness and echogenicity of vessel wall structures. In addition, the spectra information of the RF signal can facilitate the reorganization of atheroma. However, the histopathological information of the atherosclerotic cardiovascular disease is limited due to the low axial resolutions and lateral resolutions of current commercial IVUS transducer. In order to overcome these drawbacks, the focused transducer fabricated by mechanical dimpling method could be used. In order to prove the effectiveness of the focused transducer, pulse-echo experiment, wire phantom and zebra fish model were conducted. In the pulse-echo experiment, the focused transducer with 40MHz center frequency showed a broader bandwidth and higher sensitivity than the plane one. Additionally, in the B-mode experiment by using the wire phantom, focused transducer demonstrated a better axial resolution and lateral resolution. Finally, the focused transducer also has been proved have the ability to distinguish the cornea and iris of the zebra fish eye. Therefore, the IVUS system with focused transducer is a promising imaging technique to detect and diagnosis the atherosclerotic cardiovascular disease with vulnerable plaque. |
| Rights: | All rights reserved |
| Access: | restricted access |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| b28945372.pdf | For All Users (off-campus access for PolyU Staff & Students only) | 9.96 MB | Adobe PDF | View/Open |
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