Scatterer number density estimation using frequency modulated ultrasound pulse [medical images]

Ultrasound echoes backscattered from an inhomogeneous medium have the character of a random signal. If the medium is represented as a uniform matrix material with scattering bodies distributed randomly, then the scatterer number density can be estimated from the second and higher statistical moments of the signal. However, the estimate is biased because the statistical nature of the signal also depends on the resolution cell volume of the imaging system, which in turn depends on the center frequency f_o, and the bandwidth Δ f of the interrogating short pulse and the beam profile of the transducer. The authors have performed A-line simulation of the backscattered signal from a specially designed mathematical phantom. Such a phantom makes it possible to study the signal variations as a function of changing resolution cell volume