Abdominal retained surgical sponges: CT appearance

Retention of surgical sponges is rare. They cause either an aseptic reactio n without significant symptoms or an exudative reaction which results in ea rly but nonspecific symptoms. Computed tomography is very useful for recogn ition of retained sponges. The appearance of retained sponges is widely var iable. Air trapping into a surgical sponge results in the spongiform patter n which is characteristic but unfortunately uncommon. A low-density, high-d ensity,,or complex mass is found in the majority of cases, ir but these pat terns are not specific. Sometimes, a thin high-density capsule may be seen. Rim or internal calcification is a rare finding. Finally, a radiopaque mar ker is not a reliable sign. Differentiation from abscess and hematoma is so metimes difficult.