Follow-up PET/CT of alveolar echinococcosis: Comparison of metabolic activity and immunodiagnostic testing

Abstract

Purpose To investigate the potential role of follow-up 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in therapy control of inoperable patients with alveolar echinococcosis. Materials and methods In this single-center retrospective cohort study, 48 PET/CT of 16 patients with confirmed alveolar echinococcosis were analysed. FDG-uptake of the most active echinococcosis manifestation was measured (i.e., maximum standardized uptake value (SUVmax) and in relation to background activity in normal liver tissue (SUVratio)) and compared to immunodiagnostic testing. For clinical patient follow-up, patient demographics, laboratory data, including E. granulosus hydatid fluid (EgHF) antibody units (AU) as well as clinical and treatment information were assessed for all patients at the time of PET/CT, and at the last recorded clinical visit. Results Metabolic activity of PET/CT measured in the echinococcosis manifestation was significantly correlated with EgHF AU (p < 0.001). The differences in metabolic activity of echinococcosis manifestations between two consecutive PET/CT examinations of the same patient and differences in EgHF AU in the respective time intervals displayed a significant positive correlation (p = 0.01). A trend for a more rapid decline in SUVratio liver over time was found in patients who stopped benzimidazole therapy versus patients who did not stop therapy (p = 0.059). Conclusion In inoperable patients with alveolar echinococcosis, the course of metabolic activity in follow-up PET/CT is associated to the course EgHF antibody levels. Both parameters may potentially be used to evaluate the course of the disease and potentially predict the duration of benzimidazole therapy.

18FDG-PET/CT-Scans and Biomarker Levels Predicting Clinical Outcome in Patients with Alveolar Echinococcosis—A Single-Center Cohort Study with 179 Patients

“…Total IgE, parasite-specific IgE, IHA IgG titers, and Em2 + status changed significantly with increasing PNM stage. A respective correlation of serology (crude antigen preparations or the recombinant/purified antigens EM10, Em18, and Em2 + antigens) and the PNM stage has been shown previously [ 14 , 16 , 17 , 18 ] and was confirmed in our investigation.…”

“…Data from Hotz et al (2022) revealed strong correlations for both Echinococcus IgG and recEm18 serology with FDG tracer uptake in PET/CT scans [ 16 ]. Recent studies combining FDG-uptake by PET with specific serology (mainly Em18-ELISA) showed promising results regarding the safety of an STI [ 17 , 18 ].…”