In-vivo flow simulation in coronary arteries based on computed tomography datasets: feasibility and initial results

The purpose of this paper was to non-invasively assess hemodynamic parameters such as mass flow, wall shear stress (WSS), and wall pressure with computational fluid dynamics (CFD) in coronary arteries using patient-specific data from computed tomography (CT) angiography. Five patients (two without atherosclerosis, three with atherosclerosis) underwent retrospectively electrocardiogram (ECG) gated 16-detector row CT using ECG-pulsing and geometric models of coronary arteries were reconstructed for CFD analysis. Blood flow was considered laminar, incompressible, Newtonian, and pulsatile. The mass flow, WSS, and wall pressure were quantified and flow patterns were visualized. The wall pressure continuously decreased towards distal segments and showed pressure drops in stenotic segments. In coronary segments without atherosclerotic wall changes, WSS remained low, even during phases of high flow velocity, whereas in atherosclerotic vessels, the WSS was elevated already at low flow velocities. Stenoses and post-stenotic dilatations led to flow acceleration and rapid deceleration, respectively, including a distortion of flow. Areas of high WSS and high flow velocities were found adjacent to plaques, with values correlating with the degree of stenosis. CFD provided detailed mass flow measurements. CFD analysis is feasible in normal and atherosclerotic coronary arteries and provides the rationale for further investigation of the links between hemodynamic parameters and the significance of coronary stenoses.