Whole-body dynamic FDG-PET/CT Parametric Imaging in Alveolar Echinococcosis

Objective To determine the role of whole-body dynamic (WBD) / Patlak parametric ¹⁸ F-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 analysed 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). Conclusions WBD PET/CT yields higher lesion-to-background contrast and may therefore have the potential to increase sensitivity in the assessment of hepatic AE.