Ultrasound scanning.

Inflammatory or neoplastic bowel pathology is associated with thickening of the bowel wall. Ultrasound appearances reflect the pathological changes in the bowel. Crohn's disease is a transluminal disease leading to fibrosis. This fibrosis is responsible for the formation of an echo-poor halo surrounding a central echogenic zone. In the earlier stages with transmural oedema and inflammation, the halo assumes a ground glass appearance. Ulcerative colitis is a mucosal disease and hence the halo is a less prominent feature. Severe oedema in the bowel wall in fulminant ulcerative colitis can be recognized by the marked reduction of the haustral and central lumen of the colon.