Early lesions of Crohn's disease.

In its early stages, Crohn's disease may be manifested as small aphthoid ulcers. Because these ulcers are small and shallow, they are difficult or impossible to demonstrate on conventional barium-filled studies of the gastrointestinal tract. Using double contrast techniques, we have been able to demonstrate these early lesions of Crohn's disease in the colon, small bowel, and stomach. The aphthoid ulcers produce a "bulls-eye" or "target" lesion consisting of a small central collection of barium surrounded by radiolucent halo due to the granulomatous inflammation. The appearance is identical in the colon, small bowel, and stomach. The early lesions may be seen adjacent to or at a distance from a segment of more severe disease. In some patients, only these early lesions are found. The radiologic demonstration of these aphthoid ulcers allows for early diagnosis, facilitates differentiation between ulcerative and granulomatous collitis, and is important for planning appropriate therapy.