[MR defaecography for the diagnosis of obstructive defaecation disorders]

As a consequence of demographic changes, outlet obstruction represents an increasingly common disease. The presence and ample interactions of morphological and functional pathologies contribute to the complexity of pelvic floor dysfunction. Additionally, multiple compartments of the pelvic floor are frequently affected. MR defaecography allows for the simultaneous and detailed assessment of morphological as well as functional changes of the pelvic floor. Hence, this approach constitutes an integral part of the diagnostic work-up and preoperative evaluation of the anorectum. The supine patient position can be regarded as a drawback compared to conventional defaecography, as sufficient emptying of the rectum can be impaired or even rendered impossible in individual cases. This inherent disadvantage is, however, compensated by the high anatomic resolution, the possibility of multiplanar imaging, easy execution and especially the lack of ionising radiation. Consequently, MR defaecography is considered the method of choice for the routine evaluation of functional anorectal disorders.