Computed Fractional Flow Reserve Derived From Coronary CT Angiography

Fractional flow reserve is an indicator on functional assessment of coronary artery stenosis.Traditionally,it is computed by using a guide wire with pressure sensor invading in the vascular to get pressures of proximal and distal of the stenosis.However,this method requires invasion of the body,and is very complicated and expensive.As the traditional method of obtaining fractional flow reserve is defective,this paper studies a new acquisition method,that is using CT coronary angiography,combining the medical imaging and computational fluid dynamics,obtaining coronary flow reserve noninvasively,and constructing its software systems.This research is divided into three parts to implement this system,including processes of coronary CT image,numerical calculations of coronary artery flow field and numerical solution of fractional flow reserve.This subject studies the vessel segmentation algorithm of the coronary CT image,and implements the region growing algorithm based on threshold.And then improving two shortcomings on the basis of this algorithm,that is setting the scope of regional growth and adjusting regional growth threshold automatically.Combined with improvements in these two aspects,this paper implements the semi-automatic segmentation algorithm of blood vessel.This paper implements the three-dimensional geometric model reconstruction based on the segmentation of the coronary artery coronary,and divides finite element mesh of the model.And then studying the implement of combining the medical imaging and computational fluid dynamics,that is through a reasonable set of boundary condition of fluid control equations.Then researching the physical conditions and physiological conditions which is required by the calculation of coronary artery flow field,and implementing the acquisition algorithm of those conditions.Ultimately implementing the numerical solution of the coronary vessels fluid.According to the data of the coronary flow field,this paper implements the specific calculation method of fractional flow reserve,and then displays the calculated resul-ts three-dimensionally.Finally,this paper calculates the left and right coronary flow reserve fraction of a few real cases using the proposed method,and results are compared with values which obtained by the invasive method.Then this paper analyses the advantages and shortcomings of the implemented method.