Computed tomographic appearance of canine hepatic alveolar echinococcosis

Alveolar echinococcosis (AE) is caused by Echinococcus multilocularis, affecting dogs as accidental intermediate hosts. CT is increasingly used for abdominal imaging in small animals, providing valuable information, particularly for large masses and limited ultrasound accessibility. This study describes CT findings of hepatic lesions in 13 dogs with AE. All cases displayed well-defined cavitary lesions in the liver. Lesions showed minimal to no contrast uptake in the periphery, no uptake centrally, irregular internal walls, and soft tissue septa. Eight of 13 cases exhibited large cavitary masses (mean diameter 18.7 cm) with thick walls and feathery mineralization. Three of 13 cases had multiple smaller cavitary lesions with thin walls and without mineralization (mean diameter 8.4 cm). Two of 13 cases presented with both lesion types. These findings suggest two typical CT appearances correlated with AE: large thick-walled- and smaller thin-walled lesions. These groups may represent different stages of AE, with smaller lesions merging and progressing into larger ones. In conclusion, CT provides valuable information in evaluating hepatic lesions in dogs with AE. Large cavitary, thick-walled liver lesions with feathery wall mineralization, irregular inner margination, septation, and no central contrast uptake strongly indicate hepatic AE in dogs, differentiating it from other masses.