Computer Simulation of Doppler Ultrasound Blood Flow Signals Related to Stenosed Vessels Using Simulation of Pulsatile Blood Flow Behavior in Vessels with Various Stenosis Degrees

Abstract

In this study, a method has been proposed to model doppler ultrasound signals from blood flow passing through stenosed vessels using simulation of RF signals obtained from scattering points (Red blood cells) in different times and depths. In this model, it is supposed that several scattering points are randomly distributed in the vessel. The scattering points can be located in new positions based on their velocity in any time. Therefore, doppler Effect can be observed in anytime, with changing of received signals shape obtained from moving scatterers. The velocity profile of the scattering point was determined by modeling the blood flow pattern through arteries to further elucidate the Doppler spectrum of the applied ultrasound signals. A cosine stenosis shape was considered using Tu & Devil model as it is sufficiently similar to the normal shape of stenosis in the arteries. The input flow to the stenosed zone was the same as the pulsatile blood flow in the vessel, based on the Womersley model. As a result, changing of flow intensity and Reynolds number are very similar to reality. For similarity of considered fluid to blood fluid, the intended fluid is used in the form of non-Newtonian fluid. Investigation of the estimated velocity profile compared with the applied input value led to the error rate of 6% for both normal and stenosed (70%) cases, confirming the accuracy of this model and the method for simulating doppler signal.

Keywords

• doppler signal
• rf signal
• pulsatile blood flow
• non-newtonian fluid
• womersley model