A Theoretical Study of the Scattering of Ultrasound from Blood

A theoretical treatment of the scattering of ultrasound from blood is given, assuming that the blood behaves essentially as a continuum. The scattering then arises from fluctuations in the mass density and compressibility of the blood, which is caused by a fluctuation in the red cell concentration. An expression for the received signal in ultrasonic blood velocity measurements is given. The stochastic properties of the signal are discussed with reference to the information content about the velocity field of the blood. Since the signal is Gaussian, all available information is contained in the power spectrum, which is a blurred approximation to the velocity distribution in the region of observation.