X-ray Projection and Fluid Analysis of Contrast Agent Dynamics Through Stenosis

Diagnosis using the contrast CT images is a simple and minimally invasive method for estimating the functional severity of coronary stenosis. Since the contrast CT images get the distribution of the contrast agent, it is important to clarify the advection and diffusion of contrast agent in the diagnosis of stenosis severity using a CT value gradient such as Transluminal Attenuation Gradient (TAG). In this study, contrast agent flowing through stenosed tubes was imaged by X-ray simple projection. Contrast agent flowed in water or blood under steady flow conditions. The tubes were diameter of the tube was 3 and 2.1 mm, artificially stenosed with area reduction of 62% and 69% simulating a stenosed coronary artery for the case of water and blood respectively. In the case of water, the stenosis spread the contrast agent uniformly over the entire cross section. On the other hand, in the case of blood, the region with high concentration of the contrast agent existed along the tube wall. In the analysis simulating the case of blood, the jet flow was off the center of the axis and along the tube wall. However the analysis of contrast agent dynamics did not agree with the experiment. This may be affected by the fact that the analysis is sorely in consideration of advection.