- T2 hypointense rim is characteristic finding in hydatid disease
- Imaging appearance progresses through stages
- Simple unilocular cyst (type I)
- Multilocular cyst with internal duaghter cysts (type II)
- Wall calcification
- Complete wall calcification at the end of the cycle (type III)
- Cyst complication with rupture and/or infection is type IV
- Contained - floating membranes
- Communicating - contents pass into biliary radicles incorporated into pericyst
- Direct - endocyst and pericyst spillage into peritoneal cavity
- Ddx of uncomplicated hydatid cysts includes:
- simple hepatic (bile duct) cysts
- biliary cystadenoma
- biliary hamartomas are generally smaller, although similar in appearance
- Ddx of complicated cyst includes:
- Pyogenic abscesses
- biliary cystadenoma/cystadenocarcinoma
- cystic metastases