Effect of density of monitoring points for feedback in ultrasonic- measurement-integrated simulation of blood flow in the aorta with aneurysm

Acquisition of detailed information of hemodynamics is essential to develop the accurate diagnosis or treatment of serious cardiac diseases such as aortic aneurysms. However, each existing medical imaging technique provides only limited information and the technical improvement has been needed. In contrast, though in-depth information can be obtained by the numerical simulation, it has inherent problems such as the specification of boundary condition. Hence, we have proposed Ultrasonic-Measurement-Integrated (UMI) simulation as a possible way to solve those problems both in measurement and numerical simulation. The UMI simulation integrates numerical simulation and color Doppler ultrasonography so that feedback signals generated from outputs of the measurement and those indicated by the numerical simulation compensate the error of the numerical simulation. The feedback signals are added at a number of grid points defined as monitoring points. This paper deals with the effect of density of the monitoring points on the computational accuracy of UMI simulation using a simple two-dimensional model problem for the descending aorta with aneurysm. The computational accuracy is influenced by the arrangement and number of the monitoring points in the region of concern. Locally concentrated arrangement of monitoring points promotes the improvement of computational accuracy in the targeted region.