Ultrasound imaging small scatters through solid-state layer of a nonuniform thickness

The problem of ultrasound visualization of brain structures is greatly complicated by the presence of the skull, which leads to strong aberrations and attenuation of acoustic waves passing through it. The reason for this is a noticeable difference in sound velocities and acoustic impedances of cranial and soft tissues, as well as heterogeneity of the skull in thickness. In the present paper, in the two-dimensional approximation, a theoretical model is constructed for describing the propagation of acoustic waves in an inhomogeneous medium, including the presence of solid inclusions of the cranial type. On the basis of the obtained data, in the course of a numerical experiment, the possibility of obtaining an ultrasound image of the soft tissues of the brain through a non-uniform thickness solid layer in the application to transcranial diagnostics of brain structures has been analyzed.