The declared goal is imaging of the “vulnerable” atherosclerosis plaque that is most likely to rupture. Macrophage infiltration in the vessel wall has shown to be related to inflammation and inflammation is critically linked with the likelihood for the plaque to rupture. Quantitative studies with iron oxides have been successfully completed in animals where the number of macrophages was strongly related to the magnitude of the MR signal by histology. The logical next step towards translation is the application in humans. The imminent plan is to translate pre-existing molecular MR imaging techniques into the human setting and to adapt the methodology for other contrast agents as needed.
Above: striking positive signal enhancement corresponding to macrophage-rich plaque on IRON Images. On conventional magnetic resonance (MR) images, subtle areas of signal hypointensity (negative contrast) were detected in the aorta (solid arrows and overlaid regions of interest in panels B and D) of hyperlipidemic rabbits after MION-47 injection compared with baseline images (A and C). On IRON images, tissue was homogeneously suppressed at baseline (E and G), while positive signal was seen after MION-47 injection (solid arrows in panels F and H). The positive signal corresponds to iron deposition in matched slices on histology (fast nuclear red staining in panels I and K and combined acid phosphatase and Prussian blue staining in panels J and L). The dotted red lines on the MR images correspond to the cross section of the vessel. In both Watanabe and control rabbits, positive signals were present in paraspinal ribs (dotted arrows in panels F, M, and O) and in lymph nodes (arrowheads in panel O). As expected, normal rabbits showed no plaque on histology (N and P). Korosoglou et al.: J Am Coll Cardiol. 2008 Aug 5;52(6):483-91.