[Ultrasound imaging of foreign bodies--an experimental study]

In an experimental study, the US pattern of foreign materials such as are often found in wounds, was investigated. The exploration was carried out with the aid of high-resolution, mechanical US probes (10-12 MHz) used to examine foreign bodies placed in a gelatine bath and in the shoulder of a pig. The study showed that all foreign bodies that measured at least 1-2 mm in diameter were reliably detected. The intensity of the interface echoes was identical with all the materials employed, irrespective of the nature of the surface. However, the artefacts caused by the foreign bodies used revealed considerable differences. Complete acoustic shadow, acoustic attenuation, reverberation echoes and even "comet-tail" artefacts were observed. In clinical practice, familiarity with the artefacts that may be expected during sonographic exploration and localization of foreign bodies in wounds would seem to make good sense.