Hi I am Dr Mittal, Diabetician I would suggest that in this case, you avoid too much insulin The idea is that the insulin you took, brought down the sugars to quite acceptable range for the procedure. Considering that we dont really know how much insulin you take regularly, and what is your average sugar control, i would suggest not too chase after the single shot of steroid that you will probably take. A better idea would be to know the sugars after the steroid, and just befor ethe next meal and take a small additional dose at the meal following the procedure. The idea is that the doctor may ask you to be Nil By Mouth, for 4-6 hours after the contrast. In that case, any additional amount of insulin may actually cause trouble by putting you at a risk of hypoglycemia. I could help you further, if you could add the missing details. Best of luck Take plenty of fluids before the contrast Dr Mittal