MR defecography: depiction of anorectal anatomy and pathology.

With the advent of open-configuration MR systems, enabling image acquisition in a vertical patient position, MR defecography has become possible. MR defecography permits analyses of the anorectal angle, opening of the anal canal, functioning of the puborectal muscle, and descent of the pelvic floor during defecation. The rectal walls are well delineated on the GRE images, permitting visualization of intussusceptions and rectoceles. The concomitant depiction of structures surrounding the anorectal canal is helpful in the assessment of a spastic pelvic floor and the descending perineum syndrome and in permitting visualization of enteroceles. Dynamic MR defecography is an attractive alternative in the evaluation of defecation disorders.