Diagnostic criteria of hydatid disease on hepatic sonography.

Ultrasound findings in 31 patients proven to have hydatid disease of the liver are presented. Four distinct patterns are described: a single spherical cystic area; a flattened, spherical, cystic area; the appearance of a cyst within a cyst; and a complex cystic mass. In 21 cases (68 per cent), previously described pathognomonic appearances are encountered. The presence of an echogenic rim usually suggests hydatid infestation; however, it may also be seen in an amebic liver abscess. Delineation of daughter cysts within the complex internal echoes is diagnostic of an infected hydatid cyst.