An experimental study on MR imaging of atherosclerotic plaque with SPIO marked endothelial cells in a rabbit model.

Purpose: To investigate how to label macrophages in atherosclerotic plaques with superparamagnetic iron oxide (SPIO) nanoparticles and trace SPIO with MR imaging. Materials and Methods: Atherosclerotic lesions of a rabbit model were induced by a combination of high-fat and high-cholesterol diet and subsequent endothelial abrasion of the abdominal aorta. SPIO particles were pretreated with poly-L-lysine. SPIO nanoparticles and SPIO-labeled human endothelial cells (ECV-304) were IV injected into model animals, respectively. The MRI scans and histopathological examination were performed 12 h and 24 h after the injection. The imaging and histopathological data were analyzed. Results: Prussian blue staining of the vessel specimens indicated that SPIO particles were not found in the atheroma but in the Kupffer's cells of the liver after SPIO injection. However, the accumulation of SPIO particles in the atheroma was confirmed in animals received SPIO-labeled endothelial cell transplantation. The best quality MR scan sequences of rabbit abdominal aorta were T₂WI fat suppression, T₁WI, and DIR series, on which of MR image had a higher quality. Signal loss of the original incrassate plaque in the vessel wall on T₂WI was found in 6 of 10 animals received SPIO-labeled endothelial cell transplantation. Conclusion: SPIO-labeled endothelial cells were superior to SPIO for MR imaging of atherosclerotic plaques. J. Magn. Reson. Imaging 2011;. © 2011 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]