ANALYSIS OF ULTRASONIC SCATTERING IN BLOOD VIA A CONTINUUM APPROACH

Since the pioneering work by Reid et al. on measuring ultrasonic scatt ering in blood, this phenomenon has been extensively studied both theo retically and experimentally. The knowledge on ultrasonic scattering p roperties of blood is needed for the design of ultrasonic methods for measuring blood flow, and a better interpretation of ultrasonic images . The development of high frequency intravascular or intracardiac imag ing devices raises the possibility of measuring blood properties, e.g. , erythrocyte aggregation and fibrinogen concentration, in situ. A num ber of theoretical approaches have been developed to analyze this phen omenon where in general ultrasound wavelength is much greater than the erythrocytes. These results show that the backscattering coefficient of blood, defined as power backscattered by a unit volume of blood per steradian per unit incident intensity, is proportional to variance of the erythrocyte number fluctuation and backscattering cross-section o f a single erythrocyte. In this paper, we will show that similar resul ts can also be obtained by taking a continuum approach.