The MRI scanner generates a lot of noise when it is running – up to 130 decibels, louder than most rock concerts! The scan can also take over an hour to complete. If the patient moves during the scan, then the quality of the images can be seriously compromised, and they will need to be repeated. In order to keep a patient still in such a noisy environment for such a prolonged period of time we anaesthetise all cases undergoing MRI imaging. CT scans are quieter and faster, so can often be performed under sedation; however sometimes it may be safer to anaesthetise a pet for CT than sedate it and so we decide this on a case-by-case basis.