In vivo magnetic resonance imaging of atherosclerotic lesions with a newly developed Evans blue-DTPA-Gadolinium contrast medium in apolipoprotein-E-deficient mice

Background: Magnetic resonance imaging (MRI) contrast agents that specifically detect atherosclerotic plaque may be useful for the noninvasive detection of the plaque. We have recently developed a new contrast agent, Evans blue-DTPA- gadolinium (EB-DTPA-Gd), which selectively accumulates vascular lesions with endothelial removal. In this study, we examined whether EB-DTPA-Gd is also useful for in vivo imaging of atherosclerotic plaques. Methods: We used male apolipoprotein-E-deficient (ApoE-/-) mice of different ages ( 3, 6 and 12 months old) and age-matched male wild-type mice. After a single intravenous administration of EB- DTPA-Gd (160 mu M/kg body weight), MRI T-1 signal was obtained in vivo. Results: Increased signal intensity in the aortic wall was noted within 10 - 20 min after intravenous injection of EB-DTPA-Gd and was maintained for 30 min. The MRI enhancement in the aorta of ApoE-/- mice was increased in accordance with age, whereas no such enhancement was noted in wild- type mice. Histological examination demonstrated that there was a topological correlation between the site of MRI enhancement and that of atherosclerotic plaque. Conclusions: These results indicate that EB-DTPA-Gd is a useful MRI contrast medium for the in vivo detection of atherosclerotic plaques. Copyright (C) 2007 S. Karger AG, Basel.