10C-2 High Frequency Ultrasound Characterization of Blood Clotting Process: Results Obtained With Plasma and Whole Blood

In recent studies (Libgot-Calle et al. , Ultras. Med. Biol. ,2007, in press) we showed that a simultaneous measurement of high frequency acoustic parameters could provide quantitative informations regarding the coagulation of human whole blood in vitro. HF acoustic parameters were measured both in double transmission (DT) and backscattering (BS) modes and were linked to biophysical and biochemical changes in clotting blood. The aim of this study was to discriminate the respective influence of red blood cells (RBC) and plasma proteins - especially fibrin network formation - on the evolution of our DT parameters and therefore on the mechanical properties of the clot. A 30 MHz ultrasonic transducer was used to estimate acoustic velocity and integrated attenuation coefficient (IAC) in whole blood, blood with various hematocrit, plasma, and plasma with added thrombin and the results underlined a major influence of RBC on our parameters.