Abstract 2437: 18F -FDG Uptake in Arterial Plaques of Diabetic, Hyperlipidemic Swine
Background- Diabetes mellitus and hyperlipidemia are two well characterized risk factors for the development of accelerated atherosclerotic vascular disease. Identification of metabolically active plaque at risk for acute rupture remains a diagnostic challenge for the clinician. We proposed to validate that 18F-FDG uptake in various vascular beds on PET imaging identifies metabolically active plaque using an established large animal model of advanced atherosclerosis: the diabetic, hyperlipidemic pig.
Methods- Castrated male Yorkshire pigs (n=4), each weighing approximately 25kg, were treated with streptozotocin (50mg/kg) in citrate buffer for three consecutive days. The pigs were subsequently fed a daily diet of 1.5% cholesterol and 15% lard. The pigs had serial blood work to monitor blood sugar and cholesterol levels. At 30 weeks the pigs were injected with 300 MBq of 18F-FDG and imaged with whole body PET two hours later using Siemens ECAT and 3D imaging. The pigs were then sacrificed; the aorta, great vessels and iliac arteries were excised en bloc and stained with Sudan IV Red. Qualitative and quantitatitive assessments of visualized lesions were made.
Results- The pigs had an average blood glucose level of 199 mg/dL and average total cholesterol of 302 mg/dL and gained an average of 42 kg. Sudan Red staining showed uptake in the aortic arch at the take off for the great vessels, in the thoracic aorta, in the distal aorta and the iliac arteries in all pigs. 18F-FDG uptake was noted in 17 individual arteries and peak SUV were measured in grams/milliliter: in the proximal aorta (0.42–1.33, mean 0.813; p=0.05), the aortic arch (0.52– 0.75, mean 0.64; p=0.05), in the left carotid artery (0.50 – 0.589, mean 0.54; p=0.01) and in the right carotid artery (0.30 – 0.48, mean 0.39; p=0.18) and the abdominal aorta (0.43– 0.97, mean 0.68; p=0.03). In two of the pigs, 18F-FDG uptake was noted in the coronary arteries: left anterior descending (SUV =0.53) and left circumflex (SUV=0.49) in one pig and the RCA in another. Iliac arteries were obscured by bladder uptake.
Conclusions- Uptake of 18F-FDG in arterial walls on PET imaging corresponds to atherosclerotic plaque in a humanoid large animal model.