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


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 mumol/kg of Gd-DTPA or 75 mumol/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).


CONCLUSIONS
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.
Cornily
Jean-Christophe
JC
Imaging Science Laboratories, Mount Sinai School of Medicine, New York, New York 10029, USA.
Hyafil
Fabien
F
Calcagno
Claudia
C
Briley-Saebo
Karen C
KC
Tunstead
James
J
Aguinaldo
Juan-Gilberto S
JG
Mani
Venkatesh
V
Lorusso
Vito
V
Cavagna
Friedrich M
FM
Fayad
Zahi A
ZA
D000418:Albumins / Q000378:metabolism*; D000818:Animals; D001012:Aorta, Abdominal / Q000473:pathology / Q000648:ultrastructure; D050197:Atherosclerosis / Q000175:diagnosis* / Q000473:pathology; D003287:Contrast Media / Q000008:administration & dosage*; D004195:Disease Models, Animal; D019786:Gadolinium DTPA; D007089:Image Enhancement / Q000379:methods; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009389:Neovascularization, Pathologic / Q000175:diagnosis* / Q000473:pathology; D009942:Organometallic Compounds; D011817:Rabbits; D013997:Time Factors
D000418:Albumins; C440468:B-22956-1; D003287:Contrast Media; D009942:Organometallic Compounds; D019786:Gadolinium DTPA