Pictorial review of hepatic echinococcosis: Ultrasound imaging and differential diagnosis

Table 1 Comparison of clinical features between hepatic cystic echinococcosis and hepatic alveolar echinococcosis

	HCE	HAE
Endemic region	Worldwide	North America, northern and central Eurasia
Definitive host	Dogs and other canids	Red foxes and wolves
Intermediate host	Sheep, horses, cows and humans	Rats and humans
Type of growth	Concentric expansive growth	Vesicle-to-vesicle, infiltrative growth
Clinical symptoms	Epigastric discomfort and loss of appetite	Vague abdominal pain (upper right abdomen, 30%), jaundice (25%-30%), fatigue, weight loss, fever and chills
Imaging modalities	Ultrasound, CT, and MRI are used to evaluate the structures adjacent to the lesion, and FDG-PET is used to evaluate the activity of the lesion
Immunological diagnosis	Relatively specific immune response to heat-resistant B antigen, with 20%-58% negative results	Sensitive, positive immune response to specific antigens such as Em2 or Em18, with 90% positive results
Treatment methods and prognosis	Surgical removal of active hydatid cyst to avoid extravasation of cystic fluid, supplemented with drug treatment, with a good prognosis	Radical resection, supplemented with drug therapy, with poor prognosis in the late stage
Postoperative imaging follow-up duration	> 3 years	> 10 years

HCE: Hepatic cystic echinococcosis; HAE: Hepatic alveolar echinococcosis; CT: Computed tomography; MRI: Magnetic resonance imaging; FDG-PET: Fluorodeoxyglucose-positron emission tomography.