Can a lower gi or barium enema detect ulcerative colitis?

Maybe: Only direct vissualization with scope ( sigmiod or colonoscopy ) with biopsy can. Lower GI and barium enema can detect inflammation of mucosa and suggested, but you still need to have sigmoid or colonoscopy.

Yes,: a barium enema can show abnormalities that are consistent with ulcerative colitis, but a definitive diagnosis requires colonoscopy with biopsy.