LAUSR

The past 10 to 15 years have witnessed a tremendous interest in developing and validating noninvasive imaging techniques aimed at quantifying features of atherosclerotic plaque vulnerability in humans, most notably plaque inflammation. Among these, magnetic resonance imaging (MRI) with iron oxide nanoparticles has been widely investigated over the years as a mean to detect this feature of high-risk plaques.1 See Article by Stein-Merlob et al Iron oxide nanoparticles are particles containing an iron oxide core. Based on their size, they are subdivided into several types, better suited for different applications (eg, intravascular versus tissue imaging).2 Their tissue accumulation causes local magnetic field inhomogeneities that can be measured by MRI.2 Alternatively, iron oxides (such as, the dextran-coated cross-linked iron oxide nanoparticles [CLIO], used in this work)3 can be labeled with radioisotopes or fluorophores and functionalized as multimodality imaging agents detectable by positron emission tomography or near-infrared fluorescence (NIRF) imaging, alone or in combination.4 Iron oxides can be used as non-targeted agents, avidly phagocytized by inflammatory cells and cells of the reticuloendothelial system,2 or can be labeled to target and image specific molecules involved in disease processes (some examples in atherosclerosis are iron oxides targeted to oxidation-specific epitopes or to adhesion molecules on endothelial cells).5 Although targeted and functionalized nanoparticles are typically used in animal models, some nontargeted iron oxides are commercially available. Ferumoxtran-10 and ferumoxytol, an agent currently approved only for the treatment of iron-deficient anemia in patients with chronic kidney disease, are ultrasmall superparamagnetic iron oxides that are currently or have been previously clinically approved and whose use has been investigated to track plaque inflammation.6 The use of these and other iron oxides for pre clinical and clinical imaging of cardiovascular disease has been described in hundreds of publications, of which we …