Atherosclerotic lesions rich in macrophages or smooth muscle cells discriminated in rabbit iliac arteries based on T1 relaxation time and lipid content.
OBJECTIVE
Atherothrombosis usually occurs on macrophage- and lipid-rich unstable plaque, but rarely on smooth muscle cell (SMC)-rich stable plaque. Magnetic resonance imaging (MRI) has been extensively applied for noninvasive vascular imaging. We therefore investigated whether MRI provides valuable information about the characteristics of atherosclerotic vessels using rabbit models of macrophage-rich or SMC-rich atherosclerotic arteries.


METHODS
Rabbits were fed with a conventional (CD group, n = 3) or 0.5% cholesterol (ChD group, n = 3) diet for 1 week before and 3 weeks after balloon injury of the left iliac arteries. Three weeks later, these arteries were investigates by 1.5 T MRI and by conventional angiographic imaging, followed by histological and immunohistochemical analyses.


RESULTS
Three weeks after balloon injury, injured iliac arteries of both groups formed neointima with luminal stenosis. Conventional and MRI angiographic findings of the luminal diameter significantly and positively correlated. T1 relaxation time was significantly shorter and the lipid content was much higher in injured arteries from the ChD than from the CD group. The injured arteries from the ChD also contained more macrophages and less SMCs that those from the CD group. The T1 relaxation time and lipid content in injured arteries negatively and positively correlated with the degree of macrophage accumulation, respectively.


CONCLUSIONS
These results showed that MRI could provide valuable information about luminal stenosis and the characteristics of atherosclerotic vessels in rabbits.
Kuroiwa
Yasuyoshi
Y
Department of Radiological Technology, Koga General Hospital, Miyazaki, Japan.
Yamashita
Atsushi
A
Miyati
Tosiaki
T
Furukoji
Eiji
E
Takahashi
Misaki
M
Azuma
Toshiya
T
Sugimura
Hiroshi
H
Tamura
Shozo
S
Kawai
Keiichi
K
Asada
Yujiro
Y
D000818:Animals; D050197:Atherosclerosis / Q000097:blood* / Q000175:diagnosis*; D002478:Cells, Cultured; D008055:Lipids / Q000097:blood*; D008264:Macrophages / Q000378:metabolism* / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D032389:Myocytes, Smooth Muscle / Q000378:metabolism* / Q000473:pathology*; D011817:Rabbits
D008055:Lipids