SPIO accumulates in aortic plaques of atherosclerotic rabbits, producing a characteristic MRI finding. As SPIO accumulates in plaques with increased endothelial permeability and a high macrophage content, two established features of plaque inflammation, it may have a potential for noninvasive assessment of inflammatory atherosclerotic plaques.

Development of heparin-coated magnetic nanoparticles for targeted drug delivery applications

Experimental data show accumulation of superparamagnetic iron oxide (SPIO) particles in atherosclerotic plaques. SPIO uptake occurred in plaques, suggesting an increased endothelial permeability and macrophage infiltrates as signs of inflammatory plaque activity. We incidentally observed SPIO uptake in aortic and arterial wall segments in patients who had originally received the magnetic resonance (MR) contrast agent for staging lymph node metastases. Twenty patients (19 male, 1 female; mean age, 64; range, 41-78 years) with bladder or prostate cancer underwent MR imaging (MRI) using a T2*-weighted high-resolution gradient-echo sequence prior to and 24 -36 hours after intravenous injection of 2.6 mg of Fe/kg of SPIO (Sinerem ). The aorta, both common external and internal iliac, as well as both superficial femoral arteries, were retrospectively analyzed for atherosclerotic wall changes. One patient was excluded. A positive finding was defined as an area of pronounced signal loss on postcontrast images clearly confined to the arterial wall, which was absent in the precontrast examination or increased in size. Such a finding was observed in one to three arteries in 7 of the 19 patients. The pronounced signal loss in the wall of the aorta and pelvic arteries seen in part of an elderly patient population after intravenous SPIO administration strongly suggests that this contrast agent accumulates in human atherosclerotic plaques. J. Magn. Reson. Imaging 2001;14: 355-361.

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