The intensity reflection coefficient: a novel method for investigating blood

In this work, we propose a new ultrasound (US) method for blood investigation based on the measurement of the intensity reflection coefficient (IRC). It was applied to study the aggregation of porcine red blood cells (RBCs). A Couette flow system was used to control the shear rate experienced by blood samples with values of 5 s/sup -1/ and 500 s/sup -1/ corresponding, respectively, to aggregated and non aggregated RBCs. Acoustic properties or whole porcine blood versus hematocrit ranging from 0 to 50% were investigated by the means of a 10 MHz focused transducer. The relative IRC was determined and compared to the US backscatter power. The experimental results showed an equivalence between the two parameters: the IRC is it mirror function of the backscatter power. Furthermore, the transition from lower to higher shear rate was accompanied by a diminution in the level of both the backscattering power and the relative IRC.