Echinococcosis CT On the Web
American Roentgen Ray Society Images of Echinococcosis CT
Both MRI and CT scan may be used to diagnose cystic echinococcosis. MRI is usually preferred over CT scan when diagnosing cystic echinococcosis since MRI gives better visualization of cystic areas within the tissue.
Abdominal CT scan
The most important features that is associated with hepatic hydatic cysts in CT scan are:
- Fluid density cyst, with frequent peripheral focal areas of calcification
- Indicates no active infection if completely circumferential
- Septation and daughter cysts
- The water-lily sign
- Indicates a cyst with floating, undulating membrane, caused by a detached endocyst
- Hyperdense internal septa
- Representing a spoke wheel pattern within a cyst
- Fluid with variable attenuation depending on the amount of proteinaceous debris
- Dilated intrahepatic bile duct
- Due to compression or rupture of cyst into bile ducts
Chest CT scan
- Multiple or solitary cystic lesion (most common)
- Cysts with diameter of 1-20 cm
- Unilateral or bilateral cysts
- Predominantly found in the lower lobes
Radiographic and CT features may differ in complicated and uncomplicated cysts:
- Uncomplicated cysts are characterized by:
- Round or oval masses with well-defined borders
- Enhancement after contrast injection
- Hypodense content relative to the capsule
- Complicated cysts may show:
- Meniscus sign or air crescent sign
- Cumbo sign or onion peel sign
- Water-lily sign
- Consolidation adjacent to the cyst (ruptured cyst)
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