The dye can be a problem. I'm so sorry you had a bad reaction. My mom is deathly allergic to the dye, too, and her blood pressure dropped to almost nothing when she had a catherization. Is that what happened to you? How in the world can you know in advance of the test if you're going to have a problem? My CT scans have been from the neck, down. I think I've had 3 total now, all with dye, but all for different reasons. I never had a problem.
I do hope you got an answer and that next time, they will know not to give you the dye! good luck to you.