Can you please list the risks associated with the cat scan dyes?

Allergy, Kidney Dz: Biggest danger (but not very big) is having an adverse reaction to the intravenous (IV) dye. These can be allergy like or physiologic. Rate of any reaction is less than 1%, and for severe reactions about 1 per 10, 000 injections. Another concern is with possible worsening of kidney function in people who already have poorly functioning kidneys. Being well hydrated protects the kidneys.

Low risk : Ct contrast is quite safe; and vastly safer than those used in decades prior. Assuming you do not have any history of renal disease, nor diabetes, no modifications in type or dose of contrast is necessary. There is always a risk of allergic reaction, which is more likely if you have allergy to iodine (seaweed, etc).

Very safe: Low osmolarity contrast is associated with a very low incidence of acute adverse events and the bulk of these are not life-threatening. There is an overall adverse reaction rate of 0.2% for nonionic low osmolarity ct contrast