Simulation And Analysis Of Narrow Vascular Ultrasound Blood Flow Signals Based On Field Ⅱ

The ultrasound technique is one of the important methods of clinical diagnosis in the1980s and still in use for receiving the two-dimensional structural information of human tissue. The characteristics of ultrasound detection are non-invasive, easy to use, portable, safe, inexpensive, and real-time imaging. In recent years, cardiovascular and cerebrovascular diseases caused by vascular stenosis or aneurysm have been paid more and more attention by researchers. As the hemodynamic simulation study of coronary arteries can help understand the blood flow conditions and pressure gradient in the vessels, the computer simulation models are widely employed to generate the ultrasound blood flow signals in the coronary arteries for the research of the clinical cardiovascular and cerebrovascular disease.Currently, lots of studies have been devoted to the computer simulation of ultrasound images of blood flow velocity distribution in the normal vessel without the lesion vessel based on various mathematical models. The situation of blood flow in the normal artery is discussed by the related scholars with acquired ultrasound RF signal image. But the velocity distributions of blood flow in the vessels with various stenosis lesion are not discussed by applying the ultrasound RF signal method. Therefore, the ultrasound RF signals of blood flow in stenosed vessels are obtained by proposed simulation model based on the Field â…¡ for further estimating their velocity distribution images.In order to achieve this goal, the velocity distributions of pulsatile blood flow in the vessels with different degrees of stenosis are firstly acquired by using ultrasonic Doppler method. Then the ultrasound RF signal simulation model of pulsatile blood flow with the determined velocity distributions is obtained by using the Field â…¡. The specific process is that the blood flow velocity at the axis of the normal vessel is detected by ultrasound velocity measuring equipment. And then through solving the Navier-Stokes equations with input of the velocity at the axis of the normal artery, the pressure gradient and the pulsatile blood flow velocity distributions in the arteries with diverse stenosis degrees are calculated. Blood flow scatterers in the vessels with different stenosis degrees are modeled based on the known pulsatile blood flow velocity distributions, then the ultrasound RF blood flow signals are got by using the Field II. Finally, the images of simulated pulsatile blood flow velocity profiles are obtained by the autocorrelation method from ultrasound Doppler signals demodulated from RF blood flow signals by the Hilbert transform.Experimental results show that the generated velocity profile images of ultrasound RF blood flow signals are consistent with the theoretical situation. It can be concluded that the simulation model of ultrasound RF blood flow signals for the stenosed artery is efficacious and realistic, which can be used to evaluate and compare the performance of ultrasound blood flow signal analysis and feature extraction algorithm.