Double Contrast | Examination of the small intestine according to Sellink

Double Contrast

Double contrast is the term used to describe the phenomenon used for diagnostics in the small bowel examination method according to Sellink. The patient initially receives a positive contrast medium that is not absorbed by the intestine and therefore remains in the lumen. The intestine is then filled with a negative contrast medium, which ensures that the positive contrast medium is pressed against the intestinal walls and advanced through the entire intestine.

This causes the entire intestinal walls to be wetted with the positive contrast medium administered first. This causes an increase in the signal intensity at the intestinal walls, which thus shine brightly in the imaging. The negative contrast medium, which is located in the lumen of the intestine, reduces the signal intensity.

As a result, the intestinal lumen appears darker in the imaging and can be easily distinguished from the intestinal walls. This contrast is known as double contrast and enables the physician to assess the intestinal walls. The thickness of the intestinal walls, their wrinkle relief as well as constrictions (stenoses) of the intestine, abscesses, fistula ducts and tumorous masses are made visible.Sellink’s double-contrast technique plays a particularly important role in the diagnosis of chronic inflammatory bowel diseases (Crohn’s disease, ulcerative colitis).