Measurement Of Blood Flow Parameters In Embryonic Chick Heart By Spectral Domain Coherence Tomography

Congenital heart disease(CHD)has been ranked the third in the congenital malformations disease,and there are 150000～200000 newborns with CHD each year in our country.CHD has become a major public health problem that affecting children’s physical and mental health,and affecting the population quality of life,however,the aetiology of CHD is still largely unclarified.Existing studies have found that early embryonic development stage is the important period for the development of heart tissue.Embryonic heart blood flow distribution and the state,and its cause of biomechanics have very important physiological significance for cardiac gene expression,shape formation and growth in early embryonic development stage.Thus,understanding the interaction mechanism between cardiac blood flow parameters,hemodynamic forces and heart development is important for the early diagnosis and treatment of various congenital defects.Optical coherence tomography(OCT)is a new medical imaging technology and effectively supplement the part of the blank in the field of medical imaging.Based on the Michelson interference and low coherent light interference imaging principle,OCT system with the broadband light source lighting can carry on the images of the depth direction to the strong scattering medium such as biological tissues.According to the principle of imaging differences,OCT can be divided into two categories:time domain optical coherence tomography(TDOCT)and frequency domain optical coherence tomography(FDOCT).TDOCT characteristic is need the scan of the depth direction to corresponding to the different depth of the sample,and the mechanical movement limited the acquisition speed of TDOCT.With the development of the light source and CCD camera technology,the emergence of the FDOCT improve the disadvantages of TDOCT,because FDOCT implements the parallel sampling sample depth information and greatly improve the data acquisition speed of OCT system.Two experiments was finished based on the spectral domain optical coherence tomography system.One is measurement and analysis of blood flow parameters in early embryonic chick heart(HH18 stage)under the condition of environment temperature changed.Evidence have been accumulate that abnormal blood flow could lead to profound cardiac abnormalities,thus,we measured blood flow parameters in HH18 embryonic chick heart under the condition of environment temperature constant and variable,respectively,and analysis of the relationship between the environment temperature and the embryonic heart blood flow parameters.The other one is in vivo assessment of wall strain in embryonic chick heart.Two new methods achieved to the chicken embryos cardiac outflow tract wall strain measurement,and quantitative assessment of embryo heart OFT deformation characteristics.The experimental results show that two methods are free the bulk motion of the OFT during heart beating,and one of the methods realized the OFT wall strain measurement under arbitrary angle by combining Doppler angle information,the new method provides possibility for a wide range of OFT wall strain measurement.