<prompt> The indications of colonoscopy in a patient with ulcerative colitis are all of the following exceptDiagnosis of the extent of inflammationDifferentiating it from Crohns diseaseDiagnosis of toxic megacolonMonitoring the responds to treatment  <response>: .Colonoscopy is of value to rule out carcinoma. It is easiest and most direct method in establishing the diagnosis. Colonoscopy shows mucosal nodules or ulcers; caecal and ileal strictures; deformed ileo caecal valve; mucosal oedema and pseudopolyps and occasionally diffuse colitis. Biopsy can be taken to confirm the diagnosis Contraindication-Acute ulcerative colitis. ref:SRB;S manual of surgery,ed 3,pg no 514 