“…This may be explained by the widespread use in this region of Sonazoid, a contrast agent based on microspheres with perfluorobutane developed in 2007 (Daiichi Sankyo, Tokyo, Japan). In contrast to Levovist® (Shering, Berlin, Germany), SonoVie® (Bracco Imaging, Milan, Italy) contrast agents, which enhance blood vessels directly and have a rather short time window (the most informative arterial phase lasts from about 30 to 50 seconds after injection), Sonazoid also actively phagocytoses cells of the reticuloendothelial system and has an additional "Kupffer" phase of contrast (approximately 10 minutes after injection), on which liver tumours or liver metastases appear as accumulation defects against the background of enhanced surrounding parenchyma, as the number of Kupffer cells in tumours is much lower, which simplifies the positioning of the applicator [8].…”