What is MR Defecography? MR Defecography (also known as MRI of the pelvic floor, rectum and sphincter) is an imaging exam that doctors use to look at problems in the structure of the pelvic floor or problems with how these muscles are working when you move your bowels. MR Defecography is done in an MRI machine. How do I prepare for MR Defecography? There is no prep for an MR Defecography exam. It is okay for you to eat, drink, and take your medications as normal. What should I expect during the