When assessed against CT as gold standard, ultrasound diagnosis of small bowel obstruction by emergency physicians compared favourably with abdominal radiographs.

US exams were performed using a phased array probe in the bilateral colic gutters, epigastric and suprapubic regions to assess for (1) the presence of fluid-filled, dilated bowel (defined as >25mm) proximal to normal or collapsed bowel, and (2) decreased or absent bowel peristalsis (defined as back and forth movements of spot echoes inside the fluid-filled bowel). Either finding was considered ‘positive’ for small bowel obstruction.
Bedside ultrasonography for the detection of small bowel obstruction in the emergency department
Emerg Med J. 2010 Aug 22. [Epub ahead of print]