2003 Fiscal Year Final Research Report Summary
Development of Intravascular Acoustic Microscopy System
| Project/Area Number |
13557059
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
Circulatory organs internal medicine
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| Research Institution | Tohoku University |
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Principal Investigator |
SAIJO Yoshifumi Tohoku University, Institute of Development, Aging and Cancer, Instructor, 加齢医学研究所, 助手 (00292277)
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| Co-Investigator(Kenkyū-buntansha) |
KANAI Hiroshi Tohoku University, Graduate School of Engineering, Professor, 大学院・工学研究科, 教授 (10185895)
YAMBE Tomoyuki Tohoku University, Institute of Development, Aging and Cancer, Professor, 加齢医学研究所, 教授 (70241578)
NITTA Shin-ichi Tohoku University, Institute of Development, Aging and Cancer, Guest Professor, 加齢医学研究所, 客員教授 (90101138)
OKADA Nagaya Honda Electronics Co. Ltd., Researcher, 研究開発本部, 研究員
OHTSUKI Shigeo Tohoku University, Institute of Precision Measurement, Tokyo Institute of Technology, Professor, 精密工学研究所, 教授 (00016784)
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| Project Period (FY) |
2001 – 2003
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| Keywords | atherosclerosis / vulnerable plaque / intravascular ultrasound / acoustic microscopy / backscatter / tissue velocity / strain / ultrasonic tissue characterization |
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| Research Abstract |
The cause of acute coronary syndromes such as acute myocardial infarction or unstable angina has been revealed as the rupture of a vulnerable plaque in a coronary artery. The objective of the research project was to develop an intravascular acoustic microscope system applicable to clinical settings. The concrete purpose during the term of Grant-in Aid for Scientific Research was to establish an ultrasonic diagnostic system with 40 MHz frequency which can provide greater information compared with a conventional intravascular ultrasound (IVUS) system.
The radio-frequency (RF) signal from a conventional IVUS apparatus was digitized by a high speed A/D converter with a sampling frequency of 500 MSa/s. The ECG and intracoronary pressure were simultaneously digitized and stored in a workstation. Conventional IVUS images and Integrated Backscatter Imaging derived from automatic sensitivity time compensation. RF signals of the same portion in consecutive frames were analyzed and correlation and displacement were calculated. Tissue Velocity Imaging was defined as two-dimensional distribution of the displacement in 1/30 sec where the correlation was 0.7 or more. Tissue Strain Imaging was derived from the tissue velocity difference between two points considering intracoronary pressure change. Normal coronary artery, soft plaque and hard plaque were visualized by the system. The strain of the soft plaque was larger than that of normal coronary artery and the strain was greatly changed during one cardiac cycle. The clinical results suggest the efficiency of the system to assess the pathophysiology of acute coronary syndromes.
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