Small Bowel Perforations: What the Radiologist Needs to Know.

The incidence of small bowel perforation is low but can develop from a variety of causes including Crohn disease, ischemic or bacterial enteritis, diverticulitis, bowel obstruction, volvulus, intussusception, trauma, and ingested foreign bodies. In contrast to gastroduodenal perforation, the amount of extraluminal air in small bowel perforation is small or absent in most cases. This article will illustrate the main aspects of small bowel perforation, focusing on anatomical reasons of radiological findings and in the evaluation of the site of perforation using plain film, ultrasound, and multidetector computed tomography equipments. In particular, the authors highlight the anatomic key notes and the different direct and indirect imaging signs of small bowel perforation.