Role of ultrasound in the diagnosis of abdominal hydatid disease.

Experience with the use of ultrasound for investigating hydatid disease of the abdomen is reported. The presence of daughter cysts within the parent cyst gives a pathognomonic sonographic picture, whether the cyst is single or multiple. The presence of single cysts without daughter cysts is still a diagnostic problem, unless calcification is seen. Associated secondary infection changes the picture to one of a nonspecific abscess, and only the presence of additional cysts can give a clue about the etiology.