Medical imaging techniques in the evaluation of strategies for therapeutic angiogenesis.

Recent advancements in our understanding of the basic biology of angiogenesis have prompted a focus on practical applications, both in cardiovascular disease and in oncology. The focus on practical applications has stimulated development of novel noninvasive tools that provide serial assessment of ongoing vessel growth in vivo. Nuclear imaging (SPECT, PET) and x-ray angiography have been used to assess changes in perfusion and anatomic appearance, respectively, after induced neovascular development. New MRI techniques provide the ability to identify early changes in vivo that are more sensitive to detection of the effects of new vessel growth than x-ray angiography or nuclear imaging. These new MRI techniques include measurement of blood delivery to the myocardium, development of intramyocardial vasculature, and incremental changes in regional myocardial contractile function. With the combination of methods now available, we expect to be able to track key steps of angiogenesis in vivo and to assess the efficacy of angiogenic therapies. These new imaging capabilities offer crucial information which we hope will hasten the identification and deployment of effective pharmaceutical therapies as an adjunct or alternative to invasive treatments of ischemic disease by targeted stimulation of angiogenesis, and of cancer, by targeted inhibition of angiogenesis.