Abdominal X-ray interpretation: small bowel obstruction

A 45-year-old woman who had abdominal surgery several years ago presents with one day of colicky abdominal pain, vomiting and abdominal distension. A supine and an erect abdominal X-ray and an erect chest X-ray were taken. Describe and interpret the films.

Supine abdominal X-ray: multiple dilated, centrally placed loops of bowel measuring up to 4.5 cm, with mucosal folds that cross the entire width of the loops. Very little gas in the colon and rectum. No abnormal calcification and no foreign body or device.

Erect abdominal X-ray: more than three air-fluid levels. Erect chest X-ray: no free air under either hemidiaphragm.