There is a need for direct imaging of effects on tumour vasculature in assessment of response to anti-angiogenic drugs and vascular disrupting agents. Imaging tumour vasculature depends on differences in permeability of vasculature of tumour and normal tissue, which cause changes in penetration of contrast agents. Angiogenesis imaging may be defined in terms of measurement of tumour perfusion and direct imaging of the molecules involved in angiogenesis. In addition, assessment of tumour hypoxia will give an indication of tumour vasculature. The range of imaging techniques available for these processes includes positron emission tomography (PET), dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), perfusion computed tomography (CT), and ultrasound (US).
