Comparison of a Proposed Time Domain Model with the Cosine Modelling of Blood Flow Ultrasound Signal in a Cardiac Cycle

Doppler ultrasound scanning is a special ultrasound technique that evaluates blood as it flows through a blood vessel. It is an important technique for non-invasively measuring the velocities of moving particles within the body. A Doppler ultrasound test uses reflected sound waves to evaluate blood as it flows through a blood vessel. Due to the pulsatile blood flow in arteries and the random positions of red blood cells, which are known to be important factors in generating a Doppler signal, the signal is non-stationary and random. In this paper, by assuming a number of scatters that are randomly distributed in blood vessel, a flow data generation method based on the time domain approach is introduced to simulate the Doppler signal. During the cardiac cycle the spectrum shape of the signal varies. We have considered this fact by using the spectrum shape variation during a cardiac cycle as input of our model. It is considered to reach the effectiveness, which makes this method comparable to the cosine model. We have used this model to generate the Doppler signal for a normal carotid. Thereby the Doppler signals were generated for the whole cardiac cycle. This paper shows how the introduced procedure can be used to make flow data from a number of scatters in a tube. However the Doppler effect, as the scatteres move were not taken into account. We hope to be making the influence of the Doppler effect seen in our future work. The principal motivation for this simulation is followed from comparisons to previous models which encourage the future use of this model for blood flow simulation. The simulation results were compared favorably. The result gained from the time domain flow data generation showed negligible differences with the frequency domain simulations for the normal carotid artery.