Objectives

1) To learn the different causes of small bowel strictures on CT/MRI

2) To understand how the causes may be distinguished from one another

3) To recognise the limitations and pitfalls of cross-sectional imaging in assessing small bowel strictures

Background

Small bowel strictures can present in different ways, either as acute small bowel obstruction or insidiously, causing symptoms such as abdominal pain or anaemia. Small bowel is difficult to access endoscopically, therefore imaging plays an increasing role in determining the cause of small bowel symptoms and in steering management. Crohn’s disease is the most common cause of small bowel strictures, but there are many other pathologies that can present in this way which radiologists should be familiar with.

Imaging findings OR Procedure findings

The causes of small bowel strictures include Crohn’s disease which can cause inflammatory or fibrotic strictures. Other causes include primary malignant tumours such as adenocarcinoma, NET and lymphoma, metastases, particularly melanoma, infections and ischemia which can be caused by arterial occlusion or venous thrombosis. There are also other causes such as NSAID strictures, diaphragm disease and CMUSE (cryptogenic multifocal stenosing enteritis) which are better known to our gastroenterology colleagues. The imaging features of the differential causes will be presented with representative images on CT and MRI.

Conclusion

Small bowel strictures can be caused by a wide variety of different pathologies, not just Crohn’s disease. Images as well as clinical presentation should be carefully assessed to determine the cause of any small bowel stricture.