[18F]FDG Accumulation in Early Coronary Atherosclerotic Lesions in Pigs |
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Authors: | Miikka Tarkia Antti Saraste Christoffer Stark Tommi V?h?silta Timo Savunen Marjatta Strandberg Virva Saunavaara Tuula Tolvanen Jarmo Teuho Mika Ter?s Olli Mets?l? Petteri Rinne Ilkka Heinonen Nina Savisto Mikko Pietil? Pekka Saukko Anne Roivainen Juhani Knuuti |
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Institution: | 1. Turku PET Centre, University of Turku and Turku University Hospital, Turku, Finland.; 2. Research Centre of Applied and Preventive Cardiovascular Medicine, University of Turku, Turku, Finland.; 3. Heart Center, Turku University Hospital and University of Turku, Turku, Finland.; 4. Department of Forensic Medicine, University of Turku, Turku, Finland.; 5. Institute of Clinical Medicine, University of Turku, Turku, Finland.; University Hospital Medical Centre, GERMANY, |
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Abstract: | ObjectiveInflammation is an important contributor to atherosclerosis progression. A glucose analogue 18F-fluorodeoxyglucose (18F]FDG) has been used to detect atherosclerotic inflammation. However, it is not known to what extent 18F]FDG is taken up in different stages of atherosclerosis. We aimed to study the uptake of 18F]FDG to various stages of coronary plaques in a pig model.MethodsFirst, diabetes was caused by streptozotocin injections (50 mg/kg for 3 days) in farm pigs (n = 10). After 6 months on high-fat diet, pigs underwent dual-gated cardiac PET/CT to measure 18F]FDG uptake in coronary arteries. Coronary segments (n = 33) were harvested for ex vivo measurement of radioactivity and autoradiography (ARG).ResultsIntimal thickening was observed in 16 segments and atheroma type plaques in 10 segments. Compared with the normal vessel wall, ARG showed 1.7±0.7 times higher 18F]FDG accumulation in the intimal thickening and 4.1±2.3 times higher in the atheromas (P = 0.004 and P = 0.003, respectively). Ex vivo mean vessel-to-blood ratio was higher in segments with atheroma than those without atherosclerosis (2.6±1.2 vs. 1.3±0.7, P = 0.04). In vivo PET imaging showed the highest target-to-background ratio (TBR) of 2.7. However, maximum TBR was not significantly different in segments without atherosclerosis (1.1±0.5) and either intimal thickening (1.2±0.4, P = 1.0) or atheroma (1.6±0.6, P = 0.4).ConclusionsWe found increased uptake of 18F]FDG in coronary atherosclerotic lesions in a pig model. However, uptake in these early stage lesions was not detectable with in vivo PET imaging. Further studies are needed to clarify whether visible 18F]FDG uptake in coronary arteries represents more advanced, highly inflamed plaques. |
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