Sectional Imaging for Alveolar Echinococcosis

Background: , primarily affecting the liver with infiltrative, tumor-like growth. Sectional imaging plays a pivotal role in diagnosis, staging, and treatment planning. This study aimed to systematically evaluate the initial imaging findings in a cohort of patients with suspected AE, focusing on morphological and metabolic imaging features and their implications for staging and therapeutic decision-making. Methods: We retrospectively analyzed all patients who presented with suspected AE at the University Hospital Ulm between January 2019 and December 2023 and had F-18-fluorodeoxyglucose positron emission tomography (F-18-FDG-PET/computed tomography [CT] or PET/ magnetic resonance imaging [MRI]) and/or MRI within 6 months of presentation. PET imaging was visually assessed for increased FDG uptake as a marker of metabolic activity. Lesions were classified according to the Kodama MRI classification. Imaging-based staging was performed using the PNM classification and compared with the clinical PNM stage. Results: = 89), PET activity was observed in 96.4% of Kodama type 2 and 90.6% of type 3 lesions, while no FDG uptake was noted in type 5 lesions. Imaging-based PNM classification disagreed with clinical staging in 56 cases (27.6%), likely due to standardized review by experienced radiologists and nuclear medicine specialists. PET/CT proved valuable for assessing extrahepatic and distant involvement, offering a whole-body evaluation that was more consistent than MRI, which often varied in protocol and anatomical coverage. Conclusion: F-18-FDG-PET/CT is a cornerstone in the initial diagnostic workup and staging of AE, enabling both assessment of disease extent and evaluation of inflammatory activity in specialized centers. While MRI provides essential morphological details, its limited availability and heterogeneous acquisition protocols reduce its utility for comprehensive staging. Kodama lesion types correlate with metabolic activity, but further studies are needed to clarify their prognostic relevance. Our findings underscore the importance of standardized imaging protocols and the central role of PET/CT in managing newly diagnosed AE.