Whole-body dynamic FDG-PET/CT parametric imaging in alveolar echinococcosis.

Objective
To determine the role of whole-body dynamic (WBD)/Patlak parametric 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in patients with alveolar echinococcosis (AE). This technique allows separating metabolized from unmetabolized FDG in the blood pool and tissue, potentially providing complementary qualitative information and superior quantification to standard static PET/CT images.Methods
We prospectively analyzed 20 PET/CT datasets performed for staging or therapy monitoring in patients with confirmed AE. Dynamic and standard static PET/CT datasets were acquired in all patients, and quantitative imaging parameters were measured in the lesion with the highest uptake (i.e., maximum standardized uptake value (SUVmax) and Patlak parameters) and compared to normal liver tissue (SUVratio and Patlak ratio).Results
Mean SUVmax in AE manifestations was 5.7 ± 3.1 (3.2-13.9), compared to 3.2 ± 0.4 (2.5-4.2) in non-infected liver tissue, respective values for Patlak were 13.0 ± 8.6 (2.7-35.5) and 4.9 ± 2.8 (0.6-12.1). SUVratio (1.8 ± 1.1; 1.0-5.2) was significantly lower (P < 0.001) than Patlak ratio (3.2 ± 3.2; 1.1-15.6). Both ratios correlated significantly with E. granulosus hydatid fluid (EgHF) antibodies (SUVratio r = 0.73, P < 0.001; Patlak ratio r = 0.85, P < 0.001).Conclusion
WBD PET/CT yields higher lesion-to-background contrast and may, therefore, have the potential to increase sensitivity in the assessment of hepatic AE.