@nycmusic Here is an article from the National Kidney Foundation regarding contrast dyes and kidney disease:
https://www.kidney.org/kidney-topics/contrast-dye-and-kidneys
That said, it is generally thought that barium contrast dye used in digestive track procedure is okay, but caution is still advised for any other oral contrast. And remember, while one person may not have a reaction, the next person might!
Ginger

@nycmusic I can't give you a definitive answer because I usually get my CT at the cancer center I go to or at the hospital affiliated with it. I think @gingerw 's reply is the best.