A double-contrast barium enema shows 'collar-button' ulcers in the colon. This finding is characteristic of which condition?

• A Ulcerative colitis ✓
• B Crohn's disease
• C Ischaemic colitis
• D Pseudomembranous colitis

Explanation

Collar-button ulcers on double-contrast barium enema are characteristic of ulcerative colitis. They represent flask-shaped ulcers that undermine the mucosa: barium fills a narrow neck through the mucosa and then spreads laterally under the mucosa creating the collar-button shape. UC shows continuous involvement from the rectum proximally. Crohn's disease produces longitudinal (railway-track) ulcers, 'cobblestone' mucosa, skip lesions, and rose-thorn ulcers. Ischaemic colitis shows 'thumbprinting' (haustral fold thickening from submucosal haemorrhage). Pseudomembranous colitis shows shaggy mucosa with 'accordion' pattern on CT.

Reference: Grainger & Allison's Diagnostic Radiology, 7th ed.

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Written and medically reviewed by the StethoPrep medical team.