Ultrasound in the Diagnosis of Echinococcosis

Echinococcosis is a parasitic disease caused by the larva of cestode of the genus Echinococcus in humans and is a common zoonosis in pastoral areas. Since the liver is the most commonly affected organ in echinococcosis, echinococcosis typically refers to hepatic echinococcosis (HE). Two main types of HE are prevalent in humans and livestock. One is cystic echinococcosis (CE) caused by infection with Echinococcus granulosus. The other is alveolar echinococcosis (AE), which is caused by infection with Echinococcus multilocularis. Ultrasound is now widely recognized as the preferred imaging modality for diagnosing HE. It is intuitive, non-radiative, inexpensive, and has a high diagnostic accuracy rate of up to 98%. The application of ultrasound to diagnose HE began in the late 1950s and was first reported in the literature in 1964. CE and AE, the two types of echinococcosis, differ significantly in terms of morphology, epidemiology, pathology, clinical course, prognosis, and clinical treatment. Especially for AE, it has a tumor-like growth pattern and is prone to be misdiagnosed as liver cancer. Therefore, it is crucial to understand the ultrasonographic characteristics of CE and AE, respectively, to make a correct diagnosis.