Abstract 122 Evaluation Of Plaque Inflammation In A Rabbit Animal Model Of Atherosclerosis By Dynamic Contrast Enhanced MRI And 18f-fluorodeoxyglucose (18f-FDG) PET
Introduction Inflammation is a hallmark of high risk atherosclerotic plaques. Two important histological markers of plaque inflammation are the presence of neovessels and activated macrophages in the plaque. Two non-invasive imaging techniques, 18F-fluorodeoxyglucose (18F-FDG) PET and Dynamic Contrast Enhanced (DCE) MRI, have been shown to correlate with these markers. In this study we evaluate the correlation between these techniques and the presence of neovessels in a rabbit animal model of atherosclerosis.
Methods Atherosclerotic plaques were induced in the aorta of 4 New Zealand White rabbits by repeated endothelial denudation and 4 months hypercholesterolemic diet, after which imaging was performed. PET/CT was performed 3 hours after injection of 1mCi/Kg of 18F-FDG. Standard uptake value (SUV) was calculated for each acquired axial slice of the abdominal aorta. DCE-MRI was performed on a 1.5 T clinical system with a Bright Blood GE sequence. After the 5th image, 0.2 mmol/Kg of Gd-DTPA were injected intravenously. Plaque transfer constant, Ktrans, and fractional plasma volume, vp were calculated using pharmakokinetic modeling. After imaging, animals were euthanized and neovessels were detected in the atherosclerotic plaques by immuno-histology (anti-CD-31 antibody). Parameters correlation with neovessels were studied using Pearson’s test.
Results Statistical analyses showed positive correlation between neovessels count, DCE-MRI parameter vp and FDG SUV. Negative correlation was found between Ktrans, neovessels count and FDG SUV(Table 1⇓).
Conclusions This study suggests that DCE-MRI and 18F-FDG PET could be complementary used to evaluate plaque inflammation. These two techniques could thus eventually be used in the future in a clinical setting to evaluated the risk associated with the atherosclerotic lesion and to monitor lesion progression and response to therapy.