An approach of red blood cell aggregation by ultrasonic echography

The aggregation phenomenon is an important hemorheological factor which influences blood flow in human capillary bed. Aggregation can be evaluated by a number of methods but none of them can be applied simply to in vivo measurements. In contrast, use of ultrasound waves could allow measurements of mechanical and structural properties of red blood cell (RBC) suspensions as well in vitro as in vivo. To characterize more precisely and quantitatively the aggregation phenomenon, an ultrasonic method based on quantitative echography is used. The aim of this paper is to present effects of some parameters (hematocrit, dextran concentration. RBC electrical charge, shear stress) on RBC aggregation studied by ultrasonic echography. Sickle cell aggregation is also considered.