A lipopeptide-based, vascular endothelial growth factor receptor 2 (VEGRF2) -targeted contrast agent with the property of molecular imaging of angiogenesis. BR55 is prepared by incorporation of a biospecific heterodimer peptide into the perfluorobutane-containing lipid-shelled microbubble membrane; the peptide specifically binds to VEGFR2 expressed on tumoral vascular endothelium allowing ultrasound imaging of the sites of active angiogenesis.