Usefulness of the FDG PET/CT in the management of cystic echinococcosis: A pilot study

Abstract

Objectives: Cystic echinococcosis is a zoonotic disease caused by the cestode Echinococcus granulosus. The activity of the cysts is assessed through the WHO-IWGE standardized classification based on ultrasound features. However, viability of the cysts is not always concordant with the activity assessed by ultrasound. The aim of the present study is to describe the metabolic activity of cysts in patients with cystic echinococcosis through FDG-PET.

Methods: Prospective observational study where adult patients diagnosed of cystic echinococcosis were offered to undergo FDG PET/CT before treatment onset. Demographic, clinical, radiological, and histopathological information was collected from all patients.

Results: Sixteen patients were included, 50% were male, and age ranged from 18 to 85 years. Most of the patients had liver involvement, and all patients had CE3, CE4 or CE5 stage of the WHO-IWGE classification. Only one patient (CE5) had an increased ¹⁸F-FDG uptake of the cyst in the FDG PET/CT. From the 5 patients who underwent surgical treatment, only one showed signs of viability of the cyst: a patient with CE5 with no increased ¹⁸F-FDG uptake of the cyst.

Conclusion: In our pilot study, we did not find the correlation between the FDG PET/CT imaging and the cystic echinococcosis cyst bioactivity.

Keywords: Cystic echinococcosis; FDG PET/CT; Hydatid cyst; Metabolic activity.