11A-4 Molecular Imaging with Targeted Contrast Agents and High Frequency Ultrasound

Targeted ultrasound contrast agents (USCA) can be used as molecular imaging agents to visualize the expression of endothelial molecules (biomarkers). In a murine tumor model, three biomarkers for tumor vasculature were imaged using targeted USCA and the high frequency ultrasound system Vevo 770. Three biomarkers were targeted: VCAM-1, selectins (P and E), and VEGF receptors. Targeting was determined by ultrasound contrast imaging of the adhered USCA in tumors ranging in size from 3 up to 40 mm². Dependent on the tumor size, targeting of ultrasound contrast agents to the tumor vasculature resulted in significant signal enhancement when compared to control contrast agent. Each targeted contrast agent had it own accumulation level during tumor growth indicating differential expression pattern of the investigated target molecules during tumor growth. High frequency imaging with targeted ultrasound contrast can provide dynamic and quantitative information about the molecular profile of the tumor vasculature. This can open the possibility for patient-tailored therapy and can provide a tool to monitor whether the therapy is having the desired effect.