Microbubble-based contrast agents for ultrasound were introduced some time ago, although their clinical application has become widespread only in recent years. Since color and power Doppler reveal overt artifacts after microbubble injection due to the peculiar features of harmonic signals produced by insonation of microbubbles, dedicated contrast-specifi c modes of US were introduced to optimize the registration of such signals. In the past few years numerous reports have described the effectiveness of microbubble-based agents in many fi elds of clinical imaging, and the utility of microbubble- based agents in routine clinical practice is now under evaluation. The preliminary results are interesting and it seems that microbubble-based agents deserve.
