Posted 3/22/2012 1:21 PM (GMT -6)
Generally, no, you don't have to drink anything for a perianal scan. Or at least, I haven't had to.
Be prepared: they might want to stick a tiny probe up your bottom, though, that has to stay in place for the duration of the scan. They may decide not to do this if you're in lots of pain.
Good luck tomorrow,