Echinococcosis, also known as hydatid disease, is an infection of larval stage animal tapeworm, Echinococcus. The larvae reside in the liver; lungs, producing multiloculated fluid-filled cysts. Imaging findings of Echinococcosis caused by E. granulosus are single, unilocular cyst or multiseptated cysts, showing “wheel-like”, “rosette-like” or “honeycomb-like” appearances. There may be “snow-flakes” sign, reflecting free floating protoscoleces (hydatid-sand) within the cyst cavity. Degenerating cysts show wavy or serpentine bands or floating membranes representing detached or ruptured membranes. Degenerated cysts show heterogeneous, solid-looking pseudotumor that may show “ball of wool sign”. Dead cysts show calcified cyst wall. Echinococcosis caused by E. multilocularis produces multilocular alveolar cysts with exogeneous proliferation, progressively invading the liver parenchyma; other tissues of the body. Imaging findings are ill-defined infiltrating lesions of the liver parenchyma, consisting of multiple small clustered cystic; solid components. On sonography, lesions are heterogeneous with indistinct margins, showing “hailstorm appearance” or “vesicular or alveolar appearance”. CT; MR imaging displays multiple, irregular, ill-defined lesions. Multiple small round cysts with solid components are frequent. Large lesions show “geographical map” appearance. Calcifications are very frequent, appearing as peripheral calcification or punctuate scattered calcific foci. Invasion into the bile ducts, portal vein or hepatic vein may occur. Direct spread of infected tissue may result in cysts in the peritoneal cavity, kidneys, adrenal gland or bones.
Benedikt V. Czermak1 Okan Akhan2 Renate Hiemetzberger3 Bettina Zelger4 Wolfgang Vogel5 Werner Jaschke1 Michael Rieger1 Sang Yoon Kim6 Jae Hoon Lim7 Email:jhlim@smc.samsung.co.kr
[1] Department of Radiology, Medical University Innsbruck, Innsbruck, Austria ;[2] Department of Radiology, Hacettepe University School of Medicine, Sihhiye, Ankara, Turkey ;[3] Department of Cardiology, Medical University Innsbruck, Innsbruck, Austria ;[4] Department of Pathology, Medical University, Innsbruck, Austria ;[5] Department of Gastroenterology, Medical University Innsbruck, Innsbruck, Austria ;[6] Department of Pathology, Kon Kuk University, School of Medicine, Choongju, South Korea ;[7] Department of Radiology; Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Ilwon-dong, Kangnam-ku, Seoul, 135-710, South Korea
Abdominal Imaging,2008,000,1,2. no3