Evaluation of neovessels in atherosclerotic plaques of rabbits using an albumin-binding intravascular contrast agent and MRI

• Published in: Journal of magnetic resonance imaging Vol. 27; no. 6; pp. 1406 - 1411
• Main Authors: Cornily, Jean-Christophe, Hyafil, Fabien, Calcagno, Claudia, Briley-Saebo, Karen C., Tunstead, James, Aguinaldo, Juan-Gilberto S., Mani, Venkatesh, Lorusso, Vito, Cavagna, Friedrich M., Fayad, Zahi A.
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01-06-2008; Wiley-Blackwell
• Subjects: Albumins; Albumins - metabolism; Animals; Aorta, Abdominal; Aorta, Abdominal - pathology; Aorta, Abdominal - ultrastructure; Atherosclerosis; Atherosclerosis - diagnosis; Atherosclerosis - pathology; Contrast Media; Contrast Media - administration & dosage; Disease Models, Animal; Gadolinium DTPA; Human health and pathology; Image Enhancement; Image Enhancement - methods; Image Processing, Computer-Assisted; Image Processing, Computer-Assisted - methods; inflammation; Life Sciences; Magnetic Resonance Imaging; Magnetic Resonance Imaging - methods; Male; Neovascularization, Pathologic; Neovascularization, Pathologic - diagnosis; Neovascularization, Pathologic - pathology; Organometallic Compounds; plaque; Rabbits; Time Factors; Tissues and Organs
• ISSN: 1053-1807; 1522-2586
• DOI: 10.1002/jmri.21369

Purpose
To test whether B‐22956/1, a novel intravascular contrast agent with a high affinity to serum albumin (Bracco Imaging SpA.), allowed quantifying neovessel and macrophage density in atherosclerotic plaques of rabbits using MRI.
Materials and Methods
A T1‐weighted MRI of the aorta was acquired in 10 rabbits (7 atherosclerotic and 3 control rabbits) before and up to 2 h after intravenous injection of 100 μmol/kg of Gd‐DTPA or 75 μmol/kg of B‐22956/1. Plaque enhancement was measured at different time points. Immunohistochemistry was performed using anti‐CD 31 antibodies and anti‐RAM 11 antibodies to correlate to neovessel and macrophage density, respectively.
Results
MRI showed a significant plaque enhancement 2 h after B‐22956/1 versus Gd‐DTPA in the atherosclerotic group (39.75% versus 9.5%; P < 0.0001. Early atherosclerotic plaques (n = 146) enhancement positively correlates with neovessel density on corresponding histological sections (r = 0.42; P < 0.01). Enhancement of atherosclerotic plaques 2 h after injection of B‐22956/1 correlated with macrophage density (r = 0.71; P < 0.01).
Conclusion
Enhancement of atherosclerotic plaques with MRI correlated with neovessel density at early time points after the injection of B‐22956/1 and with macrophage density, at later time points. Hence, B‐22956/1‐enhanced MRI represents a promising imaging technique for the identification of “high‐risk” plaques. J. Magn. Reson. Imaging 2008;27:1406–1411. © 2008 Wiley‐Liss, Inc.