Inflammatory bowel disease : CT and MR diagnosis

Abstract

The term inflammatory bowel disease refers to two main entities, ulcerative colitis (UC) and Crohn's disease (CD). The aetiology of these two conditions is uncertain. However, it has been suggested that they are the result of genetic factors leading to an abnormal immune response within the bowel wall to normal bowel contents. UC appears to precede CD in new cases. The incidence of IBD is increasing and there is a higher incidence ofIBD in the developed world, which appears to suggest that a westernized diet may be a contributing risk factor. Endoscopy is one of the main investigations used to diagnose inflammatory bowel disease. Two techniques are available, either conventional push endoscopy or capsule endoscopy. Push endoscopy has one major limitation in that most of the small intestine is inaccessible with this technique; the proximal jejunum and the terminal ileum may be accessible, but the intervening small bowel segments are not. One advantage of push endoscopy is that it allows lesion biopsy. Capsule endoscopy does visualize the whole bowel, but there is a significant risk of capsule retention particularly in the more severe cases of CD due to bowel strictures. Capsule endoscopy does not allow biopsy.