Measurement of the bowel wall. In a patient with Crohn’s disease of the small intestine, ultrasound was applied to evaluate disease extension and wall thickness. B-mode image shows moderate wall thickening in the ileum with well-preserved layer structure. Be aware the marked thickening of the submucosal layer in white, often seen in IBD. The crosses mark the wall thickness in the anterior and posterior wall denoting a slight difference in thickening.