OUTLINE: Patients undergo contrast-enhanced ultrasonography (CEUS) before and after stabilized sulphur hexafluoride microbubble-based contrast agent injection. CEUS is done within 8 days prior to, 30 days after the first administration, and after 3 months of receiving antiangiogenesis treatment (e.g., sunitinib malate, sorafenib tosylate, or bevacizumab). Patients also undergo computed tomography and magnetic resonance imaging to evaluate tumoral targets.