Abstract: Objective To study the feasibility of noninvasive detection of unstable plaques with 18F-Fluorodeoxyglucose (18F-FDG) PET/CT imaging. Methods Atherosclerotic plaques were induced in male New Zealand white rabbits. Animals were injected with FDG labeled with 18F , then imaged with PET/CT . Aorta was explanted for photography with digital camera ,and 18F-FDG uptake analysis. 30 unstable plaques and 30 stable plaques were choosed so as to compare the quantitative 18F-FDG uptake.The number of macrophages and smooth muscle cells was detected by immunohistochemical technique. Results Experimental group showed inconsistent uptake of 18F-FDG in the abdominal aorta. The results were confirmed in the ex vivo digital photo of the explanted aorta. The target to non target ratio(T/NT) and macrophages of unstable plaques were higher than stable plaques(P<0.01), but smooth muscle cells obviously reduced (P<0.01).Correlation analysis showed that there was a positive correlation between T/NT and macrophage content( r=0.815，P<0.01), and a negative correlation between T/NT and SMC content(r=-0.684，P<0.01). Conclusion 18F-FDG PET/CT can constitute an attractive imaging method for the noninvasive detection of experimental unstable plaques.

Key words: 18F-FDG PET/CT, Unstable plaque, Macrophage, Smooth muscle cell