Computerized axial tomography (CAT): Cat scanning adds X-ray images with the aid of a computer to generate cross-sectional views anatomy. It can identify normal and abnormal structures and be used to guide procedures. CAT scanning is painless. Iodine-containing contrast material is sometimes used in CAT scanning. If you are having a CAT scan and are allergic to iodine or contrast materials, you should notify your physicians and radiology staff.