The ileum is the third and final segment of the small intestine, extending from the jejunum to the cecum at the ileocecal valve. It is responsible for absorbing nutrients not yet absorbed by the duodenum and jejunum, particularly vitamin B12 and bile salts. On ultrasound, the terminal ileum is sometimes visible in the right lower quadrant and is most commonly evaluated in the context of inflammatory bowel disease, particularly Crohn disease, which has a predilection for this location. An abnormal terminal ileum may show wall thickening, hyperemia on Doppler, and surrounding inflammatory changes, findings that help diagnose and monitor Crohn disease.
Sonography Term