Background: Imaging modalities to assess atherosclerotic plaque thrombogenicity have not been established, so in this study the relationship between [(18)F]-fluorodeoxyglucose ((18)F-FDG) uptake and thrombus formation was investigated in rabbit atherosclerotic arteries.
Methods and results: Atherosclerotic plaque was induced in the iliacofemoral artery by balloon injury and a 0.5% cholesterol diet. At 3 weeks after the first balloon injury, the arteries were visualized by (18)F-FDG positron emission tomography (PET) imaging 2h after an (18)F-FDG infusion, and then arterial thrombus was induced by a second balloon injury of both iliacofemoral arteries. Imaging with (18)F-FDG-PET revealed significantly more radioactivity along the injured (0.63 ± 0.12 SUVmax), than the contralateral non-injured artery (0.34 ± 0.08 SUV max, n=17, P<0.0001). Arterial radioactivity measured by autoradiography positively correlated with macrophage area, the number of nuclei that were immunopositive for nuclear factor κ B (NF-κB), and tissue factor (TF) expression. The immunopositive areas for glycoprotein IIb/IIIa and fibrin in thrombi were significantly larger in the atherosclerotic than in the contralateral arteries, and significantly correlated with radioactivity in PET (r=0.92, P<0.001, n=10) and autoradiography (r=0.73, P<0.0001, n=50) in the arteries. Inhibition of NF-κB significantly reduced TF expression in cultured atherosclerotic plaque.
Conclusions: Arterial (18)F-FDG uptake reflects the thrombogenicity of atherosclerotic plaque following balloon injury.