2004 Fiscal Year Final Research Report Summary
An Investigation on Noninvasive Measurement of Transmural Distribution of Myocardial Systolic Function and Diastolic Properties Using Ultrasound
| Project/Area Number |
15300177
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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 | 一般 |
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| Research Field |
Medical systems
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| Research Institution | Tohoku University |
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Principal Investigator |
KANAI Hiroshi Tohoku University, Graduate School of Engineering, Professor, 大学院・工学研究科, 教授 (10185895)
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| Co-Investigator(Kenkyū-buntansha) |
SAIJO Yoshifumi Tohoku University, Institute of Development, Aging and Cancer, Associate Professor, 加齢医学研究所, 助教授 (00292277)
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| Project Period (FY) |
2003 – 2004
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| Keywords | Ultrasonic Doppler method / Local change in thickness / Myocardial contraction / relaxation / Myocardial motility / Spectrum analysis / Color-coded display / Tissue Characterization / phased tracking method |
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| Research Abstract |
For the serious heart diseases, the different transmural layers of the myocardium have transmural heterogeneity with respect to the strength of contraction. A method for measuring such transmural heterogeneity with sufficient spatial resolution has never been developed. In this study, a method for noninvasive measurement of the intramyocardial contraction/relaxation heterogeneity by evaluating the change in thickness or its speed in two dimensions and its measurement system were developed. Moreover, a novel method for measuring the myocardial viscoelasticity was developed and its principle was confirmed by the basic experiments and in vivo experiments as follows :
1.In this study, a method for noninvasive measurement of the intramyocardial contraction/relaxation heterogeneity by evaluating the change in thickness or its speed in two dimensions and its measurement system were developed.
2.Based on the basic experiments using a spherical shell made of silicone rubber, which physical parame
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ters are known, as a heart-mimicking phantom, the accuracy of the measurement of the developed method was confirmed.
3.Moreover, this study developed the following novel method for noninvasively measuring the myocardial viscoelasticity at the beginning of diastole and for imaging the transmural heterogeneity in the propagation of the elastic waves. The method was applied to healthy subjects and patients with heart diseases. By this method, a velocity signal of the heart wall can be successfully detected with sufficient reproducibility. In this study, the pulsive waves were measured almost simultaneously at about 160 points set along the heart wall at a sufficiently high frame rate. The consecutive spatial phase distributions, obtained by the Fourier transform of the measured waves, clearly revealed wave propagation along the heart wall for the first time. Based on this phenomenon, we developed a means to measure the myocardial viscoelasticity in vivo using the model of the Lamb wave propagation in a viscoelastic plate. This method has a potential to noninvasively evaluate the myocardial viscoelasticity. Less
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