Emerging role of USPIOs for MR imaging of atherosclerosis

Atherosclerosis is an inflammatory disease of the arteries, which causes more than 19 million deaths worldwide every year. Most complications of atherosclerosis are caused by rupture of a vulnerable plaque. Currently, there are no imaging techniques available in clinical practice that can accurately identify a vulnerable plaque. There is an emerging role for Ultrasmall Super-paramagnetic Iron Oxide Particles (USPIOs) in MR imaging of atherosclerosis. This review will first give an update on the biology of atherosclerosis. Next, we will focus on the physicochemical properties of USPIOs and describe animal and human studies that showed USPIO uptake mainly in macrophages of atherosclerotic plaque, which could be detected as areas of focal signal loss in MR images. Novel superparamagnetic particles are currently being developed which enable visualization of other cell types and functions than macrophage uptake that are relevant for atherosclerosis. We conclude that USPIOs are a highly promising imaging tool for atherosclerosis and larger prospective studies are warranted to prove the value in daily clinical practice