Which of the following is the earliest sign of ulcerative colitis on double-contrast barium enema study -: (A) Mucosal granularity, (B) Loss of haustrations, (C) 'Collar - button' ulcer, (D) Lead pipe colon
Answer is A. Earliest radiological change of UC on barium enema is blurring of the mucosal lining and a fine granularity when mucosa is seen enface due to edema.
Earliest radiological change of Crohn's disease → Aphthous lesions (Bull's eye or Target lesions).