Rigler’s sign

Pneumoperitoneum. This is a nice example of Rigler’s sign (white arrows outlining both sides of the small bowel wall). This is an iatrogenic pneumoperitoneum – the patient had developed ileus two days following formation of an ileostomy and colectomy for ulcerative colitis. The stoma is visible as a soft tissue density in the RIF (yellow arrow). An NG tube is also present.