Pictorial review of hepatic echinococcosis: Ultrasound imaging and differential diagnosis

Echinococcosis is a zoonotic disease caused by parasites belonging to the genus Echinococcus that primarily affect the liver. The western plateau and pastoral areas of China are high-risk regions for hepatic cystic echinococcosis and hepatic alveolar echinococcosis (HAE). The high late mortality rate associated with HAE underscores the critical need for early diagnosis to improve cure rates and mitigate the disease burden in endemic areas. Currently, the World Health Organization recommends ultrasonography as the preferred initial screening method for hepatic echinococcosis. However, distinguishing between specific types of lesions, such as those of hepatic cystic echinococcosis and HAE, and other focal liver lesions is challenging. To address this issue, contrast-enhanced ultrasound is recommended as a tool to differentiate solid and cysto-solid hepatic echinococcosis from other focal liver lesions, significantly enhancing diagnostic accuracy. In this comprehensive review, we discuss the progression of hepatic echinococcosis and detail the imaging features of various types of echinococcosis using conventional, contrast-enhanced, and intraoperative ultrasound techniques. Our objective is to provide robust imaging evidence and guidance for early diagnosis, clinical decision making, and postoperative follow-up in regions with high disease prevalence.