Retained surgical gauzes: acute and chronic CT and US findings.

Surgical sponges retained after laparotomy represent a diagnostic problem if they cannot be identified by radiopaque markers on standard radiographs. We report on 9 patients from different hospitals with an abdominal gossypiboma 7 days to 21 years after the surgical procedure. Plain radiographs may suggest the diagnosis if a textile foreign body is calcified, that is, is equipped with radiopaque marker, or when a characteristic "whirl-like" pattern is present. CT and US are necessary procedures in chronic cases, since the lesion may mimic a mass; US shows specific echogenic areas with acoustic shadow; CT usually reveals a hypodense mass with a thick peripheral rim.