Hi
I had an "odd" reaction to the CT Scan. The injection, besides making me warm, also put me into a sneezing fit. The tech had to wait on the last scan process until I stopped sneezing, about 10 minutes. Then the office made me wait around for an hour for "observation".
So you could have had some unusual reaction. In my case, the tech said that she had seen my reaction before but it was very rare.