Is contrast mandatory for abdomen ct scan?

No: Ct scans can be done with oral, intravenous, and/or rectal contrast. The oral and rectal routes enhance visualization of upper and lower bowel segments, while the IV route enhances solid organs such as liver, kidneys, etc, than noncontrasted studies. It all depends on what ailment the scan is done for to determine contrast usage. Kidney stones are best seen with no contrast at all.

No: Iv contrast is often not used when the ct is for the purpose of looking for renal stones and in people with a history of contrast allergy or renal disease. It is often helpful in assessing persons with nonspecific abdominal symptoms as it will better show areas of inflammation, infection, and tumor.