Exploring the nature of atheroma and cardiovascular inflammation in vivo using positron emission tomography (PET)

Positron emission tomography (PET) has become widely established in oncology. Subsequently, a whole new toolbox of tracers have become available to look at different aspects of cancer cell function and dysfunction, including cell protein production, DNA synthesis, hypoxia and angiogenesis. In the past 5 years, these tools have been used increasingly to look at the other great killer of the developed world: cardiovascular disease. For example, inflammation of the unstable plaque can be imaged with 18-fludeoxyglucose (F-18-FDG), and this uptake can be quantified to show the effect that statins have in reducing inflammation and explains how these drugs can reduce the risk of stroke. F-18-FDG has also become established in diagnosing and monitoring large-vessel vasculitis and has now entered routine practice. Other agents such as gallium-68 (Ga-68) octreotide have been shown to identify vascular inflammation possibly more specifically than F-18-FDG. Hypoxia within the plaque can be imaged with F-18-fluoromisonidazole and resulting angiogenesis with F-18-RGD peptides. Active calcification such as that found in unstable atheromatous plaques can be imaged with F-18-NaF. PET imaging enables us to understand the mechanisms by which cardiovascular disease, including atheroma, leads to morbidity and death and thus increases the chance of finding new and effective treatments.