A Simulation Study of Structural Scattering in Ultrasonic B-Mode Imaging

The analysis of echographic images by means of computers is paid attention to since the last decades. Tissue models have been introduced for better understanding the interaction of ultrasound with tissues. By computer simulations, the theoretical knowledge of image formation has been greatly improved. As a first step for the characterization of liver tissue by image analysis a homogeneous tissue model, with randomly distributed point-like scatterers, was applied. However, this approach to ultrasonic imaging of liver tissue does not incorporate the so-called structural scattering. This structural component of the scattering can be related to the dimensions of the liver lobules. These are surrounded by the colageen rich triads of Kiernan which form a hexagonal matrix. Earlier studies (Sommer et al., 1981, Fellingham et al. 1984) showed a clinical application for this parameter to differentiate diffuse liver diseases. The assesment of this mean scatterer distance is based on either the statistical analysis of the spatial autocorrelation function or the analysis of the power spectrum (Fellingham et al. 1984, Insana et al. 1986, Wagner et al. 1987).