Ultrasound is a very attractive and patient-friendly imaging technique, as it is easy to use, fast and non-invasive. Nevertheless, its use is severely limited by the low stability of current contrast agents, as they contain gaseous or vaporizing phase. We developed perfluorocarbon-loaded poly(lactide-co-glycolide) nanoparticles, which are suitable for long-term imaging, in a time-scale of days. However, the mechanism of contrast generation is completely unclear. As our particles are stable in regard to their size and fluorine content upon ultrasound exposure, they likely do not contain a vaporizing phase. Thus, elucidating the structure of these nanoparticles is a key to describe the mechanism of acoustic contrast generation. As SANS has been successfully applied by other researchers to study fluorinated colloids, we propose SANS to investigate the structure of the nanoparticles.