Molecular Imaging of Aortic Aneurysms

Animal studies have demonstrated that a wide range of tracers aimed at different pathophysiological elements can be used to detect AAs. These molecular imaging probes have the potential to provide complementary functional information that goes beyond the anatomic information obtained through diagnostic echocardiography or CT studies. Although anatomic imaging cannot predict future expansion of aneurysms, the functional information provided by molecular imaging agents may be able to predict future events. For some agents, for example CNA-35 targeting of collagen and 18F-labeled NP targeted to macrophages,23 proof-of-principle studies have confirmed that molecular imaging can provide information on AA functional status. For the collagen-targeted tracer, stable Stage II AAAs have a higher signal than ruptured Stage IV AAAs, reflecting the less-compromised status of the extracellular matrix.17 For 18F -NP, low uptake was associated with low growth, whereas AAs that took up high levels of tracer expanded rapidly.23 More extensive studies, including experiments in additional models of AA, will be needed to confirm the potential prognostic value of these and other molecular imaging strategies. © 2012 American Heart Association, Inc.