Because moving is an incredibly stressful event governed almost entirely by financial constraints for most people. It is very few people that can just pack up their entire lives and move with little problem.
IV contrast can have negative effects on someone with insufficient kidney function. If she is concerned she needs to speak with her doctor or with the Radiologist/radiology tech. Performing the scans. Here is a site I found that gives pretty good information regarding CT and MRI and other types of imaging.