Imaging for Regenerative Therapy for PAD

Angiographic techniques are excellent at assessing patency and status of the larger arteries within the lower extremity in patients with peripheral artery disease (PAD), but are not quantitative and are unable to assess smaller vessels, including collaterals, or perfusion at the tissue level. The ability to image smaller vessels and measure tissue perfusion are an unmet clinical need in the evaluation of patients with PAD who are candidates for regeneration therapy with stem cells or other angiogenic therapies. Potential improvements with these therapies are more likely to be at the microvascular level, which cannot be assessed by traditional angiography. In this regard, newer techniques such as magnetic resonance imaging (MRI) perfusion imaging, positron emission tomography (PET), and contrast-enhanced ultrasound (CEU) are in various stages of development for this important use.