A small proportion of people (2-5%) find MRI examinations difficult because of the partly enclosed nature of the scanner; the same people are often uncomfortable in lifts and other enclosed spaces.
This is less of a problem for rectal MRI exams than for some other MRI exams, because your head is near the opening of the magnet.
Many MRI centers offer mild sedation (relaxing tablets or injections) to patients who know that they will find the close surroundings of the magnet uncomfortable. These treatments reduce the anxiety about being in a confined space; they are not intended to put people to sleep. If you are given a sedative injection, a pulse oxymeter will be put on one of your fingers so that the technologists can monitor your pulse and breathing.
Although these injections appear to wear off quickly (in less than an hour), they slow reaction times for some hours. Driving, and travelling alone, may be unsafe for the rest of the day after such injections. If you know that you will need a sedating injection for the MRI exam, please arrange for someone to accompany you home after the test. If you are given such an injection, you should not return to work the same day.
There is no known adverse effect of the magnetic field and radio waves used in MRI on living tissues.