Prolonged retention of oil-based iodinated contrast medium observed on plain abdominal radiograph after cesarean...

Oil-based iodinated contrast media have excellent contrast properties and are widely used for hysterosalpingographic evaluation of female infertility. On abdominal radiography and computed tomography (CT) scans, their radiodensity is similar to that of metallic objects, which can sometimes lead to diagnostic confusion in the postoperative settings. In this case, retained oil-based contrast medium was observed on an abdominal radiograph following a cesarean section, making it difficult to differentiate from an intraperitoneal foreign body from surgery.

The patient was a 37-year-old pregnant woman who was referred to our hospital at 32 weeks and 1 day of pregnancy due to complete placenta previa for management of pregnancy and delivery. An elective cesarean section was performed at 37 weeks and 3 days. A plain abdominal radiograph taken immediately after surgery revealed a near-round, hyperdense, mass-like shadow with a regular margin in the pelvic cavity. An intraperitoneal foreign body was suspected; therefore, an abdominal CT scan was performed. The foreign body was located on the left side of the pouch of Douglas and had a CT value of 7000 Hounsfield units, similar to that of metals. The CT value strongly suggested the presence of an artificial object. However, further inquiries with the patient and her previous physician revealed a history of hysterosalpingography. Accordingly, retained oil-based iodinated contrast medium was suspected, and observation of the object's course was adopted.

When intraperitoneal foreign bodies are suspected on postoperative radiographs, the possibility of oil-based iodinated contrast medium retention should be considered.