For the last image in a ct scan they injected me with some kind of contrast what was it.?

Iodine based: IV CT contrast works due to the x-ray absorption of iodine. The contrast goes out the kidneys; reasonable kidney function is needed to qualify for contrast. Another big issue is allergy. Very, very rarely life threatening acute allergy happens. Hives happen fairly commonly. A true shellfish allergy increases risk x3. Some get nauseated from the injection, a feeling of warmth, a metallic taste.

IV contrast. : IV contrast fills blood vessels and helps to identify vascular structures, differentiating them from non-vascular structures.