关键词: 应变, 血管内超声, 有限单元

Abstract: The elasticity of the artery is the important standard in judging blood vessel system，detecting plaque vulnerability and preventing blood vessel diseases.The elasticity is measured by the strain of blood vessel wall aroused by the force.Computing the strain of the blood vessel accurately is the key to judge the elasticity.The vessel wall is divided into many triangles by finite element at the foundation of IVUS image.In the two-dimension plane，three values calculated by the triangle element are line strains along x-axis and y-axis（positive strain） and the changing of the angle between lines（shear strain）.Compared with the one-dimensional strain，the result indicates that two-dimensional strain provides more references，adds the influence between adjoining dots and improves the accuracy.The experiment data proves that the analysis of two-dimensional strain fulfills the moving of the pixels in blood vessel wall.

Key words: strain, ivus, finite element