Radiographic appearances in Crohn's disease. II. The course as reflected at repeat radiography.

The course and distribution of the lesions in 174 patients with Crohn's disease were evaluated from preoperative films. In the small intestine the course was locally progressive. Colonic disease involved either the right hemicolon or the entire colon. Fluctuations of mucosal lesions were common and could explain the radiographic finding of segmental and left-sided colitis. Variations in the anatomy of the lymphatic system could explain the varying distribution of the lesions.