I went to the Er recently because my covid very suddenly restricted my breathing and I thought it was better safe than sorry. Regardless they injected me with contrast fluid to make a CT scan of my head neck and upper torso read better.
The thing about contrast fluid that I was warned about was that it would leave me with a warm sensation through my body that usually starts in the groin but goes away after a minute. I was warned of this because some people think they suddenly pissed themselves.
However for me what I experienced was a feeling like I was sitting with my taint on directly on top of a towel covered space heater and it lasted for like an hour.