PLoS ONE (Jan 2015)

[18F]FDG Accumulation in Early Coronary Atherosclerotic Lesions in Pigs.

  • Miikka Tarkia,
  • Antti Saraste,
  • Christoffer Stark,
  • Tommi Vähäsilta,
  • Timo Savunen,
  • Marjatta Strandberg,
  • Virva Saunavaara,
  • Tuula Tolvanen,
  • Jarmo Teuho,
  • Mika Teräs,
  • Olli Metsälä,
  • Petteri Rinne,
  • Ilkka Heinonen,
  • Nina Savisto,
  • Mikko Pietilä,
  • Pekka Saukko,
  • Anne Roivainen,
  • Juhani Knuuti

DOI
https://doi.org/10.1371/journal.pone.0131332
Journal volume & issue
Vol. 10, no. 6
p. e0131332

Abstract

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Inflammation 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.First, 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).Intimal 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).We 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.