Modern role of clinical ultrasound in liver abscess and echinococcosis.

In the Western world, liver abscesses are predominantly of pyogenic origin and can present a wide range of ultrasonographic features, from a solid mass to a cystic cavity. Amoebic abscesses are endemic in tropical areas and typically round single lesions. Echinococcal cyst is diagnosed by ultrasound (US). Serology is particularly useful when pathognomonic US features are absent. Treatment is determined based on the WHO ultrasonographic classification, and puncture, aspiration, injection, re-aspiration (PAIR) is a US-guided therapeutic option. Hepatic alveolar echinococcosis presents on US as a pseudotumoral mass frequently with calcifications that may invade the biliary tree and portal and hepatic veins.