Forward problem study of an effective medium model for ultrasound blood characterization

Emilie Franceschini (1) , Bloen Metzger (2) , Guy Cloutier (3)

1 LMA - Laboratoire de Mécanique et d'Acoustique [Marseille]
2 IUSTI - Institut universitaire des systèmes thermiques industriels
3 LBUM - Laboratory of Biorheology and Medical Ultrasonics

The Structure Factor Model (SFM) is a scattering model developed to simulate the backscattering coefficient (BSC) of aggregated red blood cells (RBCs). However, the SFM can hardly be implemented to estimate the structural aggregate parameters in the framework of an inverse problem formulation. A scattering model called the Effective Medium Theory combined with the SFM (EMTSFM) is thus proposed to approximate the SFM. The EMTSFM assumes that aggregates of RBCs can be treated as individual homogeneous scatterers, which have effective properties determined by the acoustical characteristics and concentration of RBCs within aggregates. The EMTSFM parameterizes the BSC by three indices: the aggregate radius, the concentration of RBCs within aggregates (also named aggregate compactness) and the systemic hematocrit. The goodness of the approximation of the EMTSFM in comparison with the SFM was then examined. Based on a two-dimensional study, the EMTSFM was found to approximate the SFM with relative errors less than 30% for a product of the wavenumber times the mean aggregate radius krag<1.32. The main contribution of this work is the parameterization of the BSC with the RBC aggregate compactness, which is of relevance in clinical hemorheology since it reflects the binding energy between RBCs.

Domaines: Ingénierie biomédicale

Emilie Franceschini, Bloen Metzger, Guy Cloutier. Forward problem study of an effective medium model for ultrasound blood characterization. IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, 2011, 58 (12), pp.2668-2679. ⟨hal-00654583⟩