What is the utility of FDG PET in nonneoplastic vascular disease?
Heart disease (the most common cause of death in the U.S.) and cerebrovascular disease in large part are due to atherosclerosis, a chronic inflammatory disorder of the arterial tree. FDG PET is useful to detect and quantify the inflammatory component of atherosclerosis during the preclinical stage of disease for cardiovascular risk stratification, and also to monitor changes in atherosclerotic inflammation following treatment. The exact mechanism of FDG uptake in atherosclerosis is unclear, but is in part due to increased glucose metabolism of macrophages in atherosclerotic plaque. In general, FDG uptake within the aorta and large arteries increases with increasing age. On FDG PET, increased FDG uptake in arterial walls, particularly of the aorta, is suggestive of atherosclerosis.
Vasculitis is an inflammatory disorder of vessels which may be due to a variety of underlying etiologies. Although tissue sampling, CT, and MRI are often used for diagnostic evaluation, FDG PET is useful to detect and quantify sites of vascular inflammation, as well as to assess the changes in inflammatory disease activity that occur following treatment. On FDG PET, increased FDG uptake in the walls of vessels, particularly when there is associated wall thickening, is suggestive of vasculitis.
Venous thrombosis is a potentially life-threatening disorder, for which prompt diagnosis and therapy are important. CT, MRI, and ultrasonography (US) are the diagnostic tests most often used for diagnostic evaluation. However, increased FDG uptake may be observed on PET in sites of venous thrombosis, most likely due to the associated accumulation of inflammatory cells. The precise role of FDG PET in the diagnostic workup of patients with suspected venous thrombosis is not currently defined and is presently a topic of clinical research study. On FDG PET, focal, linear, or curvilinear increased FDG uptake in the lumen of a vein is suggestive of thrombosis.