Bowel Obstruction: Sonographic Evaluation

US and CT are the imaging methods of choice today in suspicion of a bowel obstruction. For reasons of availability and radiation protection, US is the method of choice after clinical examination. Moreover, US is the only method allowing real-time evaluation of peristalsis. Following the detection of bowel dilatation, it must be clarified whether it is mechanical or paralytic since the treatment for each is fundamentally different. In the case of an obstruction, the questions listed above (determination of level, severity, cause, complications) must be answered. However, CT is an ideal supplement for sonographically unclear cases since it allows a better overview. Rare causes such as volvulus and internal hernias or a large bowel obstruction can also be evaluated much better with CT. The still widely used plain abdominal radiograph is unnecessary in most cases. Since small bowel obstruction can be detected up to 6 hours later on X-ray than in cross-sectional imaging procedures, it can lull the examiner into a false sense of security.