Study Of Functional Intravascular OCT For Hemodynamics And Polarization Characteristics Measurement

The Disease study of Global Burden shows that cardiovascular and cerebrovascular diseases account for about 32% of all deaths from the disease and they are the world’s leading cause of death.Intravascular optical coherence imaging(IVOCT)system obtained clinically widely use in cardiovascular and cerebrovascular interventional medicine,because it has the advantages of high resolution,high sensitivity,intravascular imaging,and it can clearly show the structural features,tissue characteristics,and even cell characteristics of atherosclerotic plaque.However,at present,IVOCT can only provide the scattering intensity imaging of blood vessels and plaques,and it is difficult to identify the plaque components.In addition,hemodynamic characteristics-Fractional Flow Reserve(FFR)is a gold standard for clinical judgment of revascularization,and it is currently obtained by the method of using pressure guidewire,but it is expensive and complicated to operate.For the above-mentioned difficult problems in the clinical,if we can create a functionalized IVOCT system which can both recognize plaque component and can measure the hemodynamic characteristics,it will be of great significance for the clinical practice of cardiovascular and cerebrovascular interventional medicine.This paper presented a functionalized IVOCT study for hemodynamics and polarization characterization.On the one hand,for the hemodynamic IVOCT method,we reconstructed the three-dimensional model of the blood vessel,and finally we calculated FFR by the fluid mechanics finite element method.On the other hand,the polarization-sensitive IVOCT was used to obtain the vascular tissue polarization information,which lays a foundation for plaque component identification.The following three aspects of work were mainly carried out:1.The blood vessel contour information can be accurately obtained by using the clinical blood vessel images obtained by IVOCT.A segmentation method based on morphological features for automatic extraction of blood vessel contours was proposed.The direction and area features of the connected area morphology were used to detect catheters and blood vessels,the blood vessel contour coordinates were obtained.2.Based on the vessel part in the DSA image,the centerline of the main vessel was extracted.The slope of the curved vessel was calculated using the center line,the slope of the vessel contour coordinates in the DSA image and the OCT image were matched,the obtained 3D point coordinates were reconstructed by 3D model,and the FFR was calculated by hemodynamic simulation.3.The basic principle and polarization demodulation algorithm of existing polarization-sensitive IVOCT were analyzed,and an improved all-fiber polarizationsensitive IVOCT system based on catheter was instrumented.The isolated cardiovascular system of pigs was used as the experimental material.The polarization demodulation algorithm based on the similar Mueller matrix was used to obtain the birefringence information.