Brookfield Zoo outside of Chicago has a whole department for imaging. It was in the local paper – Chicago Tribune a couple of years ago. I would check with the zoo. They apparently have Veterinarian Radiologist(s) that does/do all the imaging, like CT, US, Xray, maybe even MRI there.
I doubt that there are any hospitals that actually allow animals into their imaging departments. I worked at one outpatient imaging center that allowed animals for CT/Open MRI imaging for a month, one day a week after hours because the local veterinary imaging center was down for repairs. Veterinary Radiologists did the readings. They were onsite because they had to sedate the animals (only dogs and cats) to get the imaging studies done.
It was kind of fun but then it became a pain in the ass. Also very poor reimbursement.