like everyone else mentioned, the side effects aren't terrible and usually go away quickly. i find contrast very irksome, but YMMV. i always feel like i've wet myself (which is just uncomfortable) and i get hot/flushed. i also tend to feel a little jittery, which might be because of the contrast or might be because they've made me lay still and feel icky....IDK.
some people *are* allergic to the contrast, but you'll be in a facility fully equipped to handle any adverse reaction to the contrast. just fwiw, i am allergic to EVERYthing (it seems like) and i am NOT allergic to the contrast.
hugs! good luck on your test!
Megs
DD1 (13-ish)
DS (11-ish)
DD2 (5-ish)