shows haemoperitonuem, penumoperitoneum, and a constricting mass lesion
in the sigmoid colon (Fig 3). Dilated large bowel, with thinning of the
wall is noted, with mesenteric and omental inflammatory changes.
Sigmoid growth with large bowel gangrene
CT is now a routine preoperative modality for patients with colorectal
neoplasms. Colorectal neoplasms usually appear as a focal area of thickening
of the bowel wall. As opposed to wall thickening seen in non-neoplastic
diseases, the luminal surface appears irregular and lobulated. Sometimes,
applecore appearance (on air-insufflation method) or intra-luminal polypoidal
lesions are seen. Complications of neoplasms such as obstruction, perforation
and intussusception are readily detected on CT.