Magnetic resonance imaging of ruptured plaques in the rabbit with ultrasmall superparamagnetic particles of iron oxide.
BACKGROUND
Magnetic resonance imaging (MRI) enhanced with ultrasmall superparamagnetic particles of iron oxide (USPIO) has previously been evaluated in hyperlipidemic rabbits. The aim of this study was therefore to compare USPIO in ruptured and non-ruptured arteries in an atherosclerotic rabbit model.


METHODS
Atherosclerotic-like lesions were induced by the combination of endothelial abrasion and high-cholesterol diet in iliac rabbit arteries (n = 16). Rupture of atherosclerotic lesions was realized by oversized balloon angioplasty in one iliac artery, whereas the contralateral artery was used as control. USPIO (ferumoxtran-10: 1 mmol Fe/kg) was administered immediately (n = 10) or 28 days (n = 6) after injury. MRI and histological analysis were performed 7 and 35 days after injury and in control arteries.


RESULTS
In vivo MRI analysis showed extended susceptibility artifact with transluminal signal loss in all ruptured arteries 7 days after injury. In contrast, hyposignal was reduced 35 days following injury (i.e. after healing), and absent in non-ruptured arteries. Similarly, histological analysis of iron uptake was significantly increased 7 days after injury compared to healed-ruptured and control arteries.


CONCLUSIONS
Accumulation ofUSPIO is significantly increased in ruptured as compared to non-ruptured arteries in the atherosclerotic rabbit model.
Durand
E
E
Service de Cardiologie, Ap-HP, HEGP, Unité INSERM E00-16, Faculté de Médecine, Université Paris-Descartes, Paris, France. durand@necker.fr
Raynaud
J S
JS
Bruneval
P
P
Brigger
I
I
Al Haj Zen
A
A
Mandet
C
C
Lancelot
E
E
Lafont
A
A
D000818:Animals; D016477:Artifacts; D050197:Atherosclerosis / Q000473:pathology*; D005263:Femoral Artery / Q000473:pathology; D052203:Ferrosoferric Oxide / Q000494:pharmacology*; D006949:Hyperlipidemias / Q000473:pathology*; D007083:Iliac Artery / Q000473:pathology; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D011817:Rabbits; D012422:Rupture, Spontaneous
C427127:superparamagnetic blood pool agent; D052203:Ferrosoferric Oxide