Summary of Metabolic Radiotracers Used for PET/CT Imaging of Atherosclerosis
| Tracer | Metabolic targets | Advantages and key findings | Limitations | Study |
|---|---|---|---|---|
| 18F-FDG | Glucose transport and phosphorylation | Tracer is readily available and the most extensively validated in preclinical and clinical studies; uptake correlates with overall inflammatory burden of plaques, for example, macrophage content; early detection of response to statins is possible | Tracer targets nearly ubiquitous metabolic process, with limited specificity for individual cell type or phenotype | (12–15) |
| 18F-FMISO | Cellular hypoxia | Uptake is higher in symptomatic carotid plaques; positive correlation exists between 18F-FMISO and 18F-FDG uptake | Diffusion barrier limits uptake; cell specificity is lacking | (27) |
| 18F-HX4 | Cellular hypoxia | Positive correlation exists between 18F-HX4 and 18F-FDG uptake | Diffusion barrier limits uptake; cell specificity is lacking | (26) |
| 64Cu-ATSM | Cellular hypoxia | Uptake correlates with plaque hypoxia and macrophage content; hypoxic cell uptake is higher than for 18F-FMISO, and washout from normoxic tissues is faster | Diffusion barrier limits uptake; cell specificity is lacking | (28) |
| 11C-acetate | TCA, FAO, FAS, OxPhos | Focal uptake occurs in calcified plaques and arterial segments without calcifications | Half-life is short, limiting availability | (30) |
| 11C-choline | FAS, biosynthesis | Uptake is mostly in arterial segments with thickening and increased lipid content; cardiac uptake is lower than that of 18F-FDG | Half-life is short, limiting availability | (37) |
| 18F-FMC | FAS, biosynthesis | Uptake is mostly in arterial segments with thickening and increased lipid content | Tracer may be substrate for distinct set of transporters from those used to transport choline | (36) |
| 18F-FEC | FAS, biosynthesis | Uptake correlates with cardiovascular risk factors; no association exists between uptake and prior cerebrovascular or cardiovascular events | Tracer may be substrate for distinct set of transporters from those used to transport choline | (38) |
ATSM = diacetyl-bis(N4-methylthiosemicarbazone); FAO = fatty acid oxidation; FAS = fatty acid synthesis; FMC = fluoromethylcholine; FEC = fluoroethylcholine.