Sonographic Spectrum of Hydatid Disease

Abstract

Hydatid disease, caused by Echinococcus granulosus, is a parasitic disease that is endemic in many parts of the world. Hydatid cyst demonstrates a variety of imaging features, varying according to growth stage, associated complications, and affected tissue. The radiologic findings range from purely cystic lesions to a completely solid appearance. Ultrasound is the most important imaging modality for liver hydatid disease and clearly demonstrates the floating membranes, daughter cysts, and hydatid sand characteristically seen in purely cystic lesions. The radiologist's familiarity with the imaging findings of the disease is very important for earlier diagnosis and an appropriate treatment. There are several classification schemes for liver hydatid cysts based on their ultrasound appearances; the initial classification by Gharbi et al and the World Health Organization classification are the most commonly preferred. Computed tomography and magnetic resonance imaging play a key role in recognizing the complications such as rupture and infection of cysts associated with hydatid disease. Today, percutaneous treatment of liver hydatid cysts, a safe, easily applicable, and well-tolerated method, has become the most effective and reliable treatment procedure in most cases if the hydatid cyst is viable. In patients treated with the percutaneous treatment technique, a decrease in the dimensions of the cyst, solidification of the cyst contents, and irregularity in the walls of cysts are signs suggestive of cure. The radiologist should also be familiar with the postoperative follow-up ultrasound findings of hydatid cyst to prevent misinterpretation of the hypoechoic, anechoic, or hyperechoic appearance of posttreatment hydatid disease appearance as recurrence.

Subcutaneous hydatid cyst located in the popliteal fossa

“…Ultrasound is an important imaging modality for hydatid disease and may clearly demonstrate the floating membranes and daughter cysts characteristically seen in purely cystic lesions (1). Preoperative diagnosis of subcutaneous hydatid disease is also possible by FNAC; the presence of diagnostic hooklets or laminated membrane ensures correct identification.…”

“…It still constitutes a serious public health problem in endemic regions. While liver and lung are the most commonly affected areas in adults, hydatid cysts may develop in almost any part of body (1). Cystic hydatid disease can occur in all viscera and soft tissues and has a high level of recurrence accounting for about 10% (2).…”

Hydatid cyst of the submandibular region

“…Nevertheless, USG is the diagnostic test of choice for the initial work-up and is particularly useful for detection of the floating membranes, daughter cysts and hydatid sand in purely cystic lesion 10 . It is also used for staging and classification of E.granulosus infection 15 .…”

Comprehensive Evaluation of Cardiac Hydatid Using 256 Slice Dual Source CT: One Stop Shop

“…WHO Informal Working Group on Echinococcosis (IWGE) classification divides the hepatic hydatid cysts into 5 types from CE1 to CE5 with CE3 divided into "A" and "B" categories. CE1 stage is completely anechoic cyst with double line sign, CE2 is multiseptated honey comb cyst, CE3A is cyst with detached membranes (water lily sign), CE3B is cyst with daughter cyst in solid matrix, CE4 is cyst with heterogeneous contents without daughter cyst and CE5 is solid components with calcified walls [13].…”