Abdominal hydatid disease: US findings during medical treatment

US was used to prospectively study 63 patients with abdominal hydatid disease treated with benzoimidazolic compounds. The size, wall margins, and echotexture of 141 cysts were evaluated to assess their response to treatment. Forty-one cysts (29%) decreased in size (12 completely disappeared). Thirty-two cysts (22.7%) showed detachment of the membrane; in seven the detachment was complete (''water lily'' sign). Forty-two cysts (29.8%) showed gradual storage of echogenic material in their cavity; 17 of these eventually assumed a pseudo-solid pattern. Fifty-three cysts (37.6%) did not change during therapy. In 14 patients resolution of the cysts, which began during therapy, became more evident after the medical treatment was completed (6-48 months of follow-up). The US patterns seen after therapy may also be seen in long-standing untreated cases, but the decrease in cyst size, detachment of membrane, and echogenic pattern occur less frequently without therapy