I would recommend just doing both the x-ray and the C&S at the same time. Simply because my vet generally likes to get a deep culture and so she sedates the rabbit and while they are sedated they can get the x-rays.

George is my trouble rabbit, a couple weeks ago he sneezed up a big blob of white snot even though he is being nebulized with Cipro. The Culture grew no bacteria. We will retest him in February just to be sure. He however gets runny noses even on antibiotics.

If he is stressed he will get a runny nose because the adrenaline.