Quantification of [18F]-FDG uptake in atherosclerotic plaque: impact of renal function

OBJECTIVE: Impaired renal function causes both increased and prolonged tracer availability in the blood-pool which might result in increased tracer accumulation in atherosclerotic lesions. Therefore, the aim of this study was to investigate a possible correlation between the intensity of tracer uptake in atherosclerotic lesions and renal function.

METHODS: Data from 50 [18F]-FDG scans were visually evaluated for tracer uptake in vessel wall alterations. Lesions were analyzed semiquantitatively by determining the blood-pool standardized uptake values (SUV(blood-pool)s), maximum SUVs (SUV(max)s), and the target-to-background ratio (TBR). These parameters were tested for correlation with estimated glomerular filtration rate (eGFR), and cardiovascular risk factors.

RESULTS: Both SUV(blood-pool)s (r(s) = -0.32, p = 0.03) and SUV(max)s for [18F]-FDG (r(s) = -0.50, p < 0.0001) showed a significant negative correlation with eGFR. TBRs for [18F]-FDG demonstrated a significant positive correlation with eGFRs (r(s) = 0.21, p = 0.02).

CONCLUSION: This study found that both intravascular tracer availability (SUV(blood-pool)) and intralesional tracer uptake (SUV(max)) are influenced by renal function. Calculation of TBR to account for that effect may result in overcorrection in case of [(18)F]-FDG. Renal insufficiency or subclinical changes in renal function have to be considered as a confounding factor in PET of atherosclerotic lesions.