2000 Fiscal Year Final Research Report Summary
Investigation of Mechanical Effect of the Heart Wall on the Coronary Circulation on the Basis of Motion Model with Various Diseases
| Project/Area Number |
11650087
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Materials/Mechanics of materials
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| Research Institution | Nagoya University |
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Principal Investigator |
YAMADA Hiroshi Nagoya University, Graduate School of Engineering, Assistant Professor, 工学研究科, 講師 (00220400)
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| Project Period (FY) |
1999 – 2000
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| Keywords | Heart / Blood Vessel / MRI / Constitutive Equation / Strain / Motion / Finite Element Analysis / Muscular Tissue |
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| Research Abstract |
A set of magnetic resonance (MR) images at a phase of the cardiac cycle were rendered and visualized as a three-dimensional (3-D) model with commercially available software. Magnetic tags in the heart wall at the end-diastole were traced manually during the cardiac cycle. The assessment of the 2-D or 3-D deformation of the local wall region with MR images can be carried out with the developed programs. Error analysis for the motion model made with the measurement data from MR images were performed and a smoothing method was proposed to overcome the difficulty of reading the position of tags during the latter half of the cardiac cycle.
Inelastic constitutive equation for the active behavior of the blood vessels was formulated on the basis of the modeling of muscular tissues, i.e., skeletal, cardiac and smooth muscles. Finite element analyses were performed with the finite element model of the vascular wall with passive and active components, for each of which simplified constitutive equations were formulated. This model described the deformation behavior of the arteries in active state under pressurization.
Finite element analyses of the cardiac wall segment with an embedded vessel and quantitative assessment of the effect of various types of cardiac wall deformation on the resistance of blood flow were carried out. Based on these results, the effect of wall thickening in such cases of hypertrophic cardiomyopathy was studied. It was found that a large contraction was obtained in the inside of such cardiac wall while the same amount of contraction was obtained on the circumference with the same radius compared with the normal heart. It was also found that the resistance in the coronary flow increased extremely resulting form the combination of the contraction in the circumferential direction and lengthening in the radial direction of the heart wall.
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