Quantification of Dynamic [18F]FDG Pet Studies in Acute Lung Injury

Purpose: This work aims to investigate lung glucose metabolism using 2-deoxy-2-[18F]fluoro-d-glucose ([18F]FDG) positron emission tomography (PET) imaging in acute lung injury (ALI) patients. Procedures: Eleven ALI patients and five healthy controls underwent a dynamic [18F]FDG PET/X-ray computed tomography (CT) scan. The standardized uptake values (SUV) and three different methods for the quantification of glucose metabolism (i.e., ratio, Patlak, and spectral analysis iterative filter, SAIF) were applied both at the region and the voxel levels. Results: SUV reported a lower correlation than the ratio with the net tracer uptake. Patlak and SAIF analyses did not show any significant spatial or quantitative (R2 > 0.80) difference. The additional information provided by SAIF showed that in lung inflammation, elevated tracer uptake is coupled with abnormal tracer exchanges within and between lung tissue compartments. Conclusions: Full kinetic modeling provides a multi-parametric description of glucose metabolism in the lungs. This allows characterizing the spatial distribution of lung inflammation as well as returning the functional state of the tissues.