Ultrasound appearances of liver hydatid disease.

They grey scale ultrasound features of liver hydatid disease have been evaluated on 65 surgically proven cysts in 38 patients. The majority of cysts showed the well-known ultrasound pattern of simple cysts. However, a minority of lesions were either multicystic or gave the appearance of a cyst within a cyst. Occasionally cysts showed a feature which we have called "the ultrasonographic water lily sign". Hydatid sand was also occasionally seen in the most dependent portion of hydatid cysts. We have noted that if a hydatid cyst becomes secondarily infected these typical ultrasound patterns are lost and the ultrasound diagnosis may then become more difficult.