Abstract #3176

Evaluation of an Iron Oxide Contrast Agent in the Visualization of Aortic Valve Sclerosis - A Preliminary Study

Amanda M. Hamilton^1,2, Andre JL Belisle^1,2, Brian K. Rutt^2,3, Ralph Weissleder⁴, Derek R. Boughner^2,5, Kem A. Rogers¹

¹Anatomy & Cell Biology, University of Western Ontario, London, Ontario, Canada; ²Imaging, Robarts Research Institute, University of Western Ontario, London, Ontario, Canada; ³Radiology, University of Western Ontario, London, Ontario, Canada; ⁴Massachusetts General Hospital, Boston, MA, USA; ⁵Medicine, University of Western Ontario, London, Ontario, Canada

Aortic valve sclerosis (AVS) is a prevalent vascular disease with macrophage invasion as a critical pathological feature. This study tested the efficacy of identifying AVS in cholesterol-fed rabbits using passive targeting of macrophages with iron oxide-enhanced MRI. In vivo and ex vivo imaging exhibited evidence of iron oxide uptake in both control and cholesterol-fed rabbit valves. Histopathological analysis revealed iron staining in myofibroblasts in both control and cholesterol-fed rabbit valves as well as in macrophages in cholesterol-fed rabbits only. Our findings suggest that passive targeting of macrophages is insufficient for early AVS identification and macrophage-targeted contrast agents should be investigated.