What is the cause of the patients presentation?
Small bowel obstruction is the likely cause, as multiple loops of dilated small bowel are present with air-fluid levels.
What is the most common cause of a small bowel obstruction in a patient with previous abdominal surgery?
Did you notice any other findings which will help you narrow the differential?
There is branching lucency near the hilum of the liver, and a faint rounded calcified opacity to the left of the midline.
The branching lucencies projecting through the liver can be either pneumobilia or portal venous gas. Can you tell them appart on plain films? How?
Pneumobilia will be central, confined to the larger central ducts. Portal venous gas will be 'pushed' distally often to within 1cm of the hepatic surface (although such small branches will be hard to see on plain films).
Erect and supine abdominal x-rays demonstrate a number of prominent air-fluid levels located within dilated loops of small bowel. In addition, branching lucency is visible near the liver hilum. A faint rounded calcified density is visible to the left of the midline, projecting to the side of the L3/4 disc space and above the iliac crest.