Can abdominal ct with iv contrast show colorectal cancer ?

Not the best choice.: It can detect advanced stage cancer but it is not ideal. A colonoscopy would be a much better choice.

Sometime: Unfortunately the exam you mention only discloses larger tumors. A "Vitrual colonoscopy" is a more sensitive test. It involves a preparation of the bowel . The "gold standard" is, of course a colonoscopy by a Gastroenterologist, you are too young to require this on a "routine basis" Do you have symptoms???? Hope this helps Dr Z

To a certain extent: It can demonstrate tumors that are on the larger size, like multiple centimeters large and also if there are concerning lesions spread in the abdomen or to the liver. But if you have a localized polyp(small outgrowth in the colon), less than 1cm, that is cancerous, this could readily be missed. These polyps can be better visualized with a specialized form of scanning known as CT colonography.