title: Coherent and incoherent ultrasound backscatter from cell aggregates.
abstract: The effective medium theory (EMT) was recently developed to model the ultrasound backscatter from aggregating red blood cells [Franceschini, Metzger, and Cloutier, IEEE Trans. Ultrason. Ferroelectr. Freq. Control 58, 2668-2679 (2011)]. The EMT assumes that aggregates can be treated as homogeneous effective scatterers, which have effective properties determined by the aggregate compactness and the acoustical characteristics of the cells and the surrounding medium. In this study, the EMT is further developed to decompose the differential backscattering cross section of a single cell aggregate into coherent and incoherent components. The coherent component corresponds to the squared norm of the average scattering amplitude from the effective scatterer, and the incoherent component considers the variance of the scattering amplitude (i.e., the mean squared norm of the fluctuation of the scattering amplitude around its mean) within the effective scatterer. A theoretical expression for the incoherent component based on the structure factor is proposed and compared with another formulation based on the Gaussian direct correlation function. This theoretical improvement is assessed using computer simulations of ultrasound backscatter from aggregating cells. The consideration of the incoherent component based on the structure factor allows us to approximate the simulations satisfactorily for a product of the wavenumber times the aggregate radius kragaround 2.
authors.affiliation: Aix-Marseille Université, Centre National de la Recherche Scientifique, Centrale Marseille, Laboratoire de Mécanique et d'Acoustique, 4 Impasse Nikola Tesla, CS 40006, 13453 Marseille cedex 13, France.
authors.forename: Romain
authors.initials: R
authors.lastname: de Monchy
authors.affiliation: Laboratory of Biorheology and Medical Ultrasonics, University of Montreal Hospital Research Centre (CRCHUM), 900 St-Denis, Suite R11.720, Montreal H2X 0A9, Canada.
authors.forename: François
authors.initials: F
authors.lastname: Destrempes
authors.affiliation: Department of Applied Sciences, Indian Institute of Information Technology Allahabad, Jhalwa, Devghat, Allahabad 211012, India.
authors.forename: Ratan K
authors.initials: RK
authors.lastname: Saha
authors.affiliation: Laboratory of Biorheology and Medical Ultrasonics, University of Montreal Hospital Research Centre (CRCHUM), 900 St-Denis, Suite R11.720, Montreal H2X 0A9, Canada.
authors.forename: Guy
authors.initials: G
authors.lastname: Cloutier
authors.affiliation: Aix-Marseille Université, Centre National de la Recherche Scientifique, Centrale Marseille, Laboratoire de Mécanique et d'Acoustique, 4 Impasse Nikola Tesla, CS 40006, 13453 Marseille cedex 13, France.
authors.forename: Emilie
authors.initials: E
authors.lastname: Franceschini
mesh_terms: D003198:Computer Simulation; D004912:Erythrocytes; D014465:Ultrasonics