Accuracy of arterial [F]-Fluorodeoxyglucose uptake quantification: A kinetic modeling study.

UNLABELLED

2-deoxy-2- [F] fluoro-D-glucose (FDG) PET is commonly used for the assessment of vessel wall inflammation. Guidelines for analysis of arterial wall FDG signal recommend the use of the average of maximal standardized uptake value (mean SUV) and target-to-blood (mean TBR) ratio. However, these methods have not been validated against a gold standard such as tissue activity ex vivo or net uptake rate of FDG (K) obtained using kinetic modeling. We sought to evaluate the accuracy of mean SUV and mean TBR for aortic wall FDG signal quantification in comparison with the net uptake rate of FDG.

METHODS

Dynamic PET data from 13 subjects without prior history of cardiovascular disease who enrolled in a study of vascular inflammation were used for this analysis. Ex vivo measurement of plasma activity was used as the input function and voxel-by-voxel Patlak analysis was performed with t* = 20 minute to obtain the K image. The FDG signal in the ascending aortic wall was quantified on PET images following recent guidelines for vascular imaging to determine mean SUV and mean TBR.

RESULTS

The K in the ascending aortic wall did not correlate with mean SUV (r = 0.10, P = NS), but correlated with mean TBR (r = 0.82, P < 0.001) (Figure 1B). K and K strongly correlated (R = 0.96, P < 0.0001) and similar to K, K did not correlate with mean SUV (r = 0.17, P = NS), but correlated with mean TBR (r = 0.83, P < 0.001).

CONCLUSIONS

Kinetic modeling supports the use of mean TBR as a surrogate for the net uptake rate of FDG in the arterial wall. These results are relevant to any PET imaging agent, regardless of the biological significance of the tracer uptake in the vessel wall.