Multimodality imaging of vascular endothelial growth factor and vascular endothelial growth factor receptor expression

Angiogenesis is a critical process in both physiological development and many pathological processes. Vascular endothelial growth factor ( VEGF)/VEGF receptor (VEGFR) signaling pathway plays a pivotal role in regulating angiogenesis. Many therapeutic agents targeting VEGF and VEGFR are currently in preclinical and clinical development. The ability to quantitatively image VEGF/VEGFR expression in a noninvasive manner can aid in lesion detection, patient stratification, new drug development/validation, treatment monitoring, and dose optimization. It can also help in decide when or whether to start anti- angiogenic treatment targeting VEGF/VEGFR. This review summarizes the recent advances in multimodality imaging of VEGF/VEGFR expression using ultrasound, optical fluorescence, optical bioluminescence, SPECT, and PET in many diseases such as cancer, myocardial infarction, and ischemia. Much research effort will be needed in the future to improve the in vivo stability, tumor targeting efficacy, and pharmacokinetics of the imaging probes. With the development of new tracers with better targeting efficacy and desirable pharmacokinetics, clinical translation will be critical for the maximum benefit of VEGF/VEGFR targeted imaging agents.