Monte Carlo simulation of ultrasound backscattering by aggregating red blood cells

When blood flows at a low shear rate, red cells aggregate and form clusters that affect vascular resistance to flow and blood echogenicity. This study intends to clarify the relation between the red cell aggregation level and the ultrasonic backscatter increase. Red cell positioning in plasma is modeled by a 2D Markov point process at a 40% hematocrit. A square well potential is adopted to take into account the erythrocyte adhesive interaction energy. Monte Carlo simulations of the point process and computations of the mean structure factor enables to assess the frequency dependence of the blood backscatter for different aggregation potentials. The ultrasonic sensitivity to the erythrocyte clustering phenomenon is demonstrated and could be used as a noninvasive measurement method of blood microstructure and rheology.