Delayed 18F-fluorodeoxyglucose PET/CT imaging improves quantitation of atherosclerotic plaque inflammation: Results from the CAMONA study

Abstract

Delayed (18)FDG PET/CT imaging at 180 minutes improves quantitation of atherosclerotic plaque inflammation over imaging at 90 minutes. Therefore, the optimal acquisition time-point to assess atherosclerotic plaque inflammation lies beyond the advocated time-point of 90 minutes after (18)FDG administration.

18F-FDG PET/CT for the quantification of inflammation in large carotid artery plaques

“…4,10,[14][15][16][17] For circulation times above one hour, the blood background is low, but highly variable, whereas carotid plaques have consistent uptake over time. 11,13 A slight variation in blood background will therefore give significant variability in TBR. From a physics perspective, Huet et al 9 have explained that there is no legitimate rationale for using TBR instead of SUV because blood contamination is an additive and not a multiplicative process.…”

“…8,9 Different acquisition protocols and quantification methods have been suggested. [10][11][12][13][14][15][16][17] They all address the same concerns but have diverging solutions. A literature search identified 53 different acquisition protocols, 51 different reconstruction protocols, and 46 different quantification methods used in 49 studies.…”

“…18 Subanalysis looking for the most metabolically active areas of a vessel segment have been used in therapy response studies. 16 The uptake values are either normalized to the blood background activity, 15,17,19,20 corrected for the background activity with subtraction 11 or not corrected for background activity. 13,21,22 The rationale for background correction has been strongly criticized.…”

Optimizing FDG-PET/CT imaging of inflammation in atherosclerosis

“…Optimal circulation time of 18F-FDG for arterial imaging may be longer than 90 minutes, but authors note that more comparative studies are needed to define it. [9][10][11] Similarly, even moderate hyperglycaemia can lower 18F-FDG uptake by plaque cells. 10 This is probably mainly based on competition between glucose and 18F-FDG as metabolic substrates and more tracer remains in circulation.…”

What can be and what cannot be accomplished with PET to detect and characterize atherosclerotic plaques

“…38 For example, we have employed this methodology in detecting uptakes of FDG and NaF in atherosclerotic plaques with high sensitivity. 21,[44][45][46][47][48][49] Specifically, we have validated measurements of global coronary artery calcification with NaF-PET in animals and human studies.…”