Case of rectal carcinoma 

Barium enema is a good method of detection. The views required are anteroposterior (AP), lateral and oblique. Single contrast study is adequate to demonstrate mucosal irregularity.

Mucosal irregularity noted on AP and lateral views coupled with the narrowing indicate a circumferential lesion.

Further evaluation and staging of cancer is carried out with CT or MRI. MRI is preferred as it provides better soft tissue differentiation.