Evaluation of cell concentration from ultrasound backscattering signals using envelope statistics analysis

Anomalies in the cell concentration of biological tissues or fluids can be related to diseases such as bacterial meningitis. As a result of meningitis, certain amount of leukocytes reaches the cerebrospinal fluid which is otherwise essentially acellular. This work proposes the use of envelope statistics to estimate the cell concentration in cerebrospinal fluid from the echo envelope of ultrasound backscattering signals. Several statistical distributions have been proposed to model the distribution of the amplitudes of the echo envelope. One of the most versatile models is the Homodyned-K distribution, which characterizes a typical scattering medium in a general way, even at low scatterer concentration and at non-random scatterer distribution. The analysis of this distribution provides a parameter (μ) which is directly related with the density of scatterers in the media. An algorithm which calculates that parameter μ from these backscattering signals was developed. The efficiency of the algorithm was evaluated from simulations of waves reflected by cell suspension. The range of concentrations and cell size were chosen for their relevance in the meningitis screening application. A linear relation between the concentration and the parameter μ was obtained showing the ability of the method to characterize the cellularity from an ultrasound image.Anomalies in the cell concentration of biological tissues or fluids can be related to diseases such as bacterial meningitis. As a result of meningitis, certain amount of leukocytes reaches the cerebrospinal fluid which is otherwise essentially acellular. This work proposes the use of envelope statistics to estimate the cell concentration in cerebrospinal fluid from the echo envelope of ultrasound backscattering signals. Several statistical distributions have been proposed to model the distribution of the amplitudes of the echo envelope. One of the most versatile models is the Homodyned-K distribution, which characterizes a typical scattering medium in a general way, even at low scatterer concentration and at non-random scatterer distribution. The analysis of this distribution provides a parameter (μ) which is directly related with the density of scatterers in the media. An algorithm which calculates that parameter μ from these backscattering signals was developed. The efficiency of the algorithm was evalu...