MR defecography can also add clinical benefit in patients with rectal disorders by revealing additional clinically occult abnormalities such as enteroceles that alter patient management [35,87,88]. A study by Rentsch et al [36] demonstrated that, in patients with posterior compartment symptoms and defecatory dysfunction, MR defecography demonstrated multifocal defects in a significant number of patients and revealed defects in addition to clinical diagnoses in 34% of cases. Use of rectal contrast and imaging during defecation are particularly important when performing MR defecography for assessment of defecatory dysfunction [89]. Multiple studies have demonstrated the added benefit of MRI with rectal contrast and the defecation phase for assessment of POP compared with dynamic straining MRI without rectal contrast or defecation [15,26-29]. Although upright MR defecography may be preferred over supine MR defecography for evaluation of defecatory dysfunction, most centers lack an open magnet to allow imaging in upright position. Studies comparing MR defecography in supine position to that in upright position have shown variable results, with some reporting that MR defecography in supine positioning may underestimate detection and size of rectal intussusception and rectocele [30,31], whereas others [32] demonstrate no significant difference in prevalence of anorectal descent during defecation when comparing the two positions. Regardless of positioning, patients should be asked to perform repeated strain/defecation maneuvers to maximize pelvic floor dysfunction seen on MRI [33]. MR defecography in patients with fecal incontinence reveals excessive perineal descent, rectoceles, and rectal intussusceptions, which can alter surgical management [90]. MR defecography has moderate to good correlation with surgical findings for diagnosis of full thickness rectal prolapse, internal rectal prolapse, posterior colopocele, rectocele, and peritoneocele [23].
Pelvic Floor Dysfunction in Females. MR defecography can also add clinical benefit in patients with rectal disorders by revealing additional clinically occult abnormalities such as enteroceles that alter patient management [35,87,88]. A study by Rentsch et al [36] demonstrated that, in patients with posterior compartment symptoms and defecatory dysfunction, MR defecography demonstrated multifocal defects in a significant number of patients and revealed defects in addition to clinical diagnoses in 34% of cases. Use of rectal contrast and imaging during defecation are particularly important when performing MR defecography for assessment of defecatory dysfunction [89]. Multiple studies have demonstrated the added benefit of MRI with rectal contrast and the defecation phase for assessment of POP compared with dynamic straining MRI without rectal contrast or defecation [15,26-29]. Although upright MR defecography may be preferred over supine MR defecography for evaluation of defecatory dysfunction, most centers lack an open magnet to allow imaging in upright position. Studies comparing MR defecography in supine position to that in upright position have shown variable results, with some reporting that MR defecography in supine positioning may underestimate detection and size of rectal intussusception and rectocele [30,31], whereas others [32] demonstrate no significant difference in prevalence of anorectal descent during defecation when comparing the two positions. Regardless of positioning, patients should be asked to perform repeated strain/defecation maneuvers to maximize pelvic floor dysfunction seen on MRI [33]. MR defecography in patients with fecal incontinence reveals excessive perineal descent, rectoceles, and rectal intussusceptions, which can alter surgical management [90]. MR defecography has moderate to good correlation with surgical findings for diagnosis of full thickness rectal prolapse, internal rectal prolapse, posterior colopocele, rectocele, and peritoneocele [23].